SCIENTIFIC AMERICAN SUPPLEMENT NO. 787

NEW YORK, January 31, 1891

Scientific American Supplement. Vol. XXXI., No. 787.

Scientific American established 1845

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Scientific American and Supplement, $7 a year.

THE FRENCH IRONCLAD WAR SHIP
COLBERT.

THE FRENCH IRONCLAD WAR SHIP COLBERT.

The central battery ironclad Colbert is one of the ten ships of
the French navy that constitute the group ranking next in
importance to the squadron of great turret ships, of which the
Formidable is the largest. The group consists of six types, as
follows:

The Colbert was launched at Brest in 1875, and her sister ship,
the Trident, in 1876. Both are of iron and wood, and the following
are the principal dimensions of the Colbert, which apply very
closely to the Trident: She is 321 ft. 6 in. long, 59 ft. 6 in.
beam, and 29 ft. 6 in. draught aft. Her displacement is 8,457 tons,
her indicated horse power is 4,652, and her speed 14.4 knots. She
has coal carrying capacity for 700 tons, and her crew numbers 706.
The thickness of her armor belt is 8.66 in., that protecting the
central battery is 6.29 in. thick, which is also the thickness of
the transverse armored bulkheads, while the deck is 0.43 in. in
thickness. The armament of the Colbert consists of eight 10.63 in.
guns, two 9.45 in., six 5.51 in., two quick firing guns, and
fourteen revolving and machine guns.—Engineering.

A compound locomotive, built by the Rhode Island Locomotive
Works, has been tried on the Union Elevated Railroad, Brooklyn,
N.Y. The engine can be run either single or compound. The economy
in fuel was 37.7 per cent, and in water 23.8 per cent, over a
simple engine which was tested at the same time. The smoothness of
running and the stillness and comparative absence of cinders was
fully demonstrated.

STEAM ENGINE VALVES.¹

By THOMAS HAWLEY.

RIDING CUT-OFF VALVES—PECULIARITIES AND MERITS OF THE
DIFFERENT STYLES.

In considering the slide valve in its simple form with or
without lap, we find there are certain limitations to its use as a
valve that would give the best results. The limitation of most
importance is that its construction will not allow of the proper
cut off to obtain all the benefits of expansion without hindering
the perfect action of the valve in other particulars. At this
economical cut off the opening of the steam port is very little and
very narrow, and although this is attempted to be overcome by
exceedingly wide ports, sixteen inches in width in many cases in
locomotive work, this great width adds largely to the unbalanced
area of the valve. The exhausting functions of the valve are
materially changed at the short cut off, and when much lap is added
to overcome this defect, there usually takes place a choking of the
exhaust port. You might inquire, why not make the port wider, but
this would increase the minimum amount of load on the valve, and
this must not be overlooked. Then the cut off is a fixed one, and
we can govern only by throttling the pressure we have raised in the
boiler or by using a cut off governor and the consequent wastes of
an enormous clearance space. You will observe, therefore, that the
plain slide valve engine gives the most general satisfaction at
about two-thirds cut off and a very low economic result. The best
of such engines will require forty-five to fifty pounds of steam
per horse power per hour, and to generate this, assuming an
evaporation of nine pounds of water to a pound of coal, would
require between five and six pounds of coal per horse power per
hour. And the only feature that the valve has specially to commend
it is its extreme simplicity and the very little mechanism required
to operate it.

Yet this is of considerable importance, and in consideration of
some special features at its latest cut off, the attempt has been
many times made to take advantage of these features. For instance,
at 90° advance, the valve opens very rapidly indeed and fully
satisfies our requirements of a perfect valve. This is one good
point, and in this position also the exhaust and compression can be
regulated very closely and as desired without much lap, and as the
opening of the exhaust port comes with the eccentric at its most
rapid movement the release is very quick and as we would have it.
This is only possible at the most uneconomic position of the valve
as regards cut off.

The aim of many engineers has been to take advantage of these
matters by using the valve with 90° angular advance of
eccentric ahead of crank, for the admission, release, and
compression of the steam, and provide another means of cutting off,
besides the one already referred to, viz., cutting off the supply
of steam to the chest, and overcome the objection in this one of
large clearance spaces. This is done by means of riding cut off
valves, often called expansion valves, of which, perhaps, the most
widely known types in this vicinity are the Kendall & Roberts
engine and the Buckeye. The former is used in the simplest form of
riding cut off, while the Buckeye has many peculiar features that
engineers, I find, are too prone to overlook in a casual
examination of the engine. In these uses of the slide valve, too,
means are suggested and carried out of practically balancing the
valve.

The origin of the riding cut off is most generally attributed to
Gonzenbach. His arrangement had two steam chests, the lower one
provided with the ordinary slide valve of late cut off, and steam
was cut off from this steam chest by the expansion valve covering
the ports connecting with the upper steam chest. This had the old
disadvantage that all the steam in the lower chest expanded with
that in the cylinder, at a consequent considerable loss. This was
further improved by causing the riding cut off to be upon the top
of the main valve, instead of its chest, and resulted in a
considerable reduction of the clearance space.

This is the simplest form, and is shown in Fig. 1. The steam is
supplied by a passage through the main valve which operates exactly
as an ordinary slide valve would. That is, the inside edges of the
steam passage are the same as the ordinary valve, the additional
piece on each end, if I may so term it, being merely to provide a
passage for the steam which can be closed, instead of allowing the
steam to pass the edge. The eccentric of the main valve is fastened
to the shaft to give the proper amount of lead, and the desired
release and compression, and the expansion valve is operated by a
separate eccentric fastened in line with or 180° ahead of the
crank. When the piston, therefore, commences to move from the crank
end to open the port, D, the expansion valve is forced by its
eccentric in the opposite direction, and is closing the steam port
and would have closed it before the piston reached quarter stroke,
thus allowing the steam then in the cylinder to do work by
expansion. The eccentric operating this expansion valve may be set
to close this steam port at any point in the stroke that is
desired, the closing occurring when the expansion valve has covered
the steam port. Continuing the movements of the valves, the two
would move together until one or the other reached its dead center,
when the movements would be in opposite directions.

FIG. 1

There are three ways of effecting the cut off in such engines,
the main valve meanwhile being undisturbed, its eccentric fastened
securely so as not to disturb the points of lead, release, and
compression. All that is required is to cause the edge of the
expansion valve to cover the steam port earlier in the stroke, and
this can be done, first, by increasing the angular advance of the
cut off eccentric; second, by adding lap to the cut off valve; and
third by changing the throw of the eccentric. In all these
instances the riding valve is caused to reach the edge of the steam
port earlier in the stroke. We will take first, as the simplest,
those methods by which the lap of the cut off valve is
increased.

It will be noted that there is but one edge of this valve that
is required to do any work, and that is to close the valve. The
eccentrics are so placed that the passage in the main valve is
opened long before the main valve itself is ready to admit steam to
the cylinder, so that only the outer edges are the ones to be
considered, and it will be readily seen that the two valves
traveling in opposite directions, any lap added to the working edge
of the cut off valve will cause it to reach the edge and therefore
close the port earlier than it would if there was less lap. And we
might carry it to the extreme that we could add lap enough that the
steam passage would not be opened at all.

In Fig. 2 is shown the method by which this is accomplished, in
what is called Meyer’s valve, and such as is used in the Kendall
& Roberts engine. We have only one point to look after, the cut
off, so we can add all the lap we wish without disturbing anything
else. In this engine the lap is changed by hand by means of a
little hand wheel on a stem that extends out of the rear of the
steam chest. The valve is in two sections, and when it is desired
to cut off earlier, the hand wheel is turned in such a direction
that the right and left hand screws controlling the cut off valve
move one valve portion back and the other forward, which would, if
they were one valve and they should be so considered, have the
effect of lengthening them, or adding lap to them. The result would
be that the riding valve would reach the edge of the steam port
earlier in the stroke, bringing about an earlier cut off. If the
cut off is desired to be later, the hand wheel is so turned that
the right and left hand screws will bring the valve sections nearer
together, thus practically taking off lap. Now this may be done by
hand or it may be done by the action of a governor.

FIG. 2

In the latter case the governor at each change of load turns the
right and left hand screws to add or take away lap, as the load
demands an earlier or later cut off; in other cases the governor
moves a rack in mesh with a gear by which the valve sections are
brought closer together or are separated. The difficulty with the
case where the hand wheel is turned by hand is that the cut off is
fixed where you leave it, and governing can only be at the
throttle. For this reason anywhere near full boiler pressure would
not be obtained in the cylinder of the engine. If the load was a
constant one, and the cut off could be fixed at about one-third,
causing the throttle to open its widest, very good results would be
obtained, but there is no margin left for governing.

If the load should increase at such a time the governor could
not control it under these conditions, and it would lead to a
decrease in speed unless the lap was again changed to give a later
cut off. On this account the general practice soon becomes to leave
the cut off at the later point and give range to the throttle, and
we come back once more to the plain slide valve cutting off at half
stroke, and the only gain there is, is in a quick port opening and
quick cut off. But these matters are more than offset by the wire
drawing between the steam pipe and chest, through the throttle, and
the fact that there is added to the friction of the engine the
friction of this additional slide valve and a considerable
liability to have a leaky valve.

In the case where the governor changes the position of the cut
off valve a greater decree of economy would result. In this engine,
of which the Lambertville engine is a type, the main valve is a
long D slide, with multiple ports at the ends through which the
steam enters the cylinders. It is operated from an eccentric on the
crank shaft in the usual manner. The cut off valve is also operated
from the motion on an eccentric fixed upon the crank shaft. The rod
or stem of the cut off valve passes through the main valve rod and
slide. Upon the outer end of the cut off valve rod are tappets
fastened to engage with tappets on the eccentric valve rod.
Connection between the cut off eccentric, therefore, and the cut
off valve is only by means of the engagement of these tappets. The
eccentric rod is fastened to a rocker arm having motion swinging
about a pin or bearing in the governor slide, which may be raised
or lowered by a cam operated by the governor. The cut off slide is
of cylindrical shape and incloses a spring and dash pot with disks
attached by means of which the valve is closed. The motion for
operating the valves is relatively in the same direction, the cut
off eccentric having the greatest throw and greater angular advance
to cause it to open earlier and quickly before the main valve is
ready to admit steam. The cut off eccentric rod swinging the rocker
arm, the tappets thereon engage with those upon the cut off valve
rod and open the passages to the main valve, and in their movement
compress the spring in the main valve. According as the speed of
the engine, the rock arm will be raised or lowered so that the
tappets upon the eccentric rod may keep in engagement a shorter or
longer time before they disengage, thus allowing the spring that
has been compressed by the movement of the cut off valve to close
that valve quickly and the supply of steam to the engine, the cut
off valve traveling with the main valve for the balance of the
stroke. This device will give a remarkably quick opening and a
quick cut off, but in view of the fact that the governor has so
much to do, its delicacy is impaired and a quick response to the
demands of the load changing not so likely to occur. The cut off
cannot be as quick as in some other engines, because the valves are
moving in opposite directions, and while this fact would help, so
far as shortening the distance to be traveled before cut off, the
resistance of the valves to travel in opposite directions, or
rather the tendency of the valve to travel with the main valve,
hinders its rapid action.

FIG. 3

This is one great objection to the rack and gear operated by the
governor, that two flat valves riding upon each other and sliding
in opposite directions at times require a considerable amount of
force to move them, and as only a slight change in load is required
by the load, the governor cannot handle the work as delicately as
it should. It is too much for the governor to do well. To overcome
this difficulty the Ryder cut-off, shown in Fig. 3, was made by the
Delamater people, of New York. The main slide valve is hollowed in
the back and the ports cut diagonally across the valve to form
almost a letter V. The expansion valve is V-shaped, and circular to
fit its circular-seat. The valve rod of the expansion valve has a
sector upon it and operated by a gear upon the governor stem, which
rotates the valve rod, and the edge of the valve rod is brought
farther over the steam port, thus practically adding lap to the
valve. Little movement is found necessary to make the ordinary
change in cut-off, and it is found to be much easier to move the
riding valve across the valve than in a direction directly
opposite. It would require considerable force to move the upper
valve by the governor faster than the lower, or in a direction
opposite to that in which it is moving, but very little force
applied sideways at the same time it is moving forward will give it
a sideways motion. In this device the governor has only to exert
this side pressure and therefore has less to do than if it were
called upon to move the upper valve directly against the movement
of the lower.

Something similar is the valve of the Woodbury engine, of
Rochester, N.Y. The cut-off valve is cylindrical, covering diagonal
ports directly opposite, and is caused to be rotated by the action
of the governor that operates a rack in mesh with a segment. Very
little movement will effect a considerable change in the lappage of
the valve, the valve turning about one-quarter a revolution for the
extremes of cut off. The cut off valve rod works through a bracket
and its end terminates in a ball in a socket on the end of the
eccentric rod. In this case the governor has not as much to do as
in other instances.

FIG. 4

Still another method of effecting this change in cut off, but
hardly by increasing the lap of the valve, is shown in the next
drawing, Fig. 4. The cut off valve is held upon the main valve by
the pressure of steam upon its back and rides with it until it
comes in contact with the cut off wedge-shaped blocks, when its
motion is arrested, and the main valve continuing its movement the
steam port is closed by the main valve passing beneath the cut off
valve. Thus the main valve travels and carries the cut off valve
upon its back again until the cut off valve strikes the wedge on
the other end and the cut off is effected. The relative positions
of the blocks are determined by the governor, that will raise or
lower them so that the cut off valve will engage with them earlier
or later as desired. This device was designed specially as an
inexpensive method of changing the common slide valve into an
automatic cut off. The cut off would not be as quick as in other
cases we have cited, depending here upon the movement of the lower
valve alone, and that, too, is in its slowest movement; whereas in
the other cases, the edges approaching each other, by the differing
movement of the valves the cut off is very rapid, provided the
distance to travel is not long. In this device considerable noise
must result by the cut off valve striking the cut off blocks, and a
considerable amount of leakage is likely to occur past this
valve.

But there is one great objection in the valve gears thus far
cited, that the travel of the expansion valve upon the main valve
is variable. I have in mind the case of a Kendall & Roberts
engine, which had been run for a long time at no better economy
than would be obtained from a plain slide valve engine, and when it
was attempted to get an earlier cut off by separating the two cut
off valves, they had worn so much in their old place on the valve
that shoulders were found sufficient to cause a disagreeable noise
and a leaky valve. This is very apt to occur, not only where the
valve is run for a long time on one seat, but in cases of variation
of the travel of the expansion valve. The result is that a change
will bring about a leaky valve, something that every engineer
abhors.

The construction of the Buckeye engine, which is also of this
type, is such that the travel of the valve on the back of the main
valve is always the same, no matter what the cut off may be. Then
this engine makes use of our second proposition as a means of
effecting the cut off, viz., by advancing the eccentric. You will
readily observe that anything that will cause the cut off valve to
reach a certain point earlier in the stroke will bring about an
earlier cut off as it hastens everything all around. This is the
plan pursued in the Buckeye, in which the governor, of the shaft
type, turns the eccentric forward or back according as the load
demands. Then, in addition, the valve is balanced partially, the
attempt not being made to produce an absolutely balanced valve, on
the ground that there should be friction enough to keep the
surfaces bright and to prevent leakage. The most perfect valve
will, of course, be entirely balanced under all conditions of
pressure so as to move with perfect ease. With the riding cut off
valve in connection with the plain slide valve, this is not
accomplished, and it does not matter whether it is partially
unbalanced to prevent leakage or not, the fact that it is not
entirely balanced prevents it reaching the ideal valve.

FIG. 5

This valve, Fig. 5, differs from the others also in this
particular, that the exhaust takes place at the end of the valve
instead of under the arch. Two eccentrics are used, the one for the
main valve being fastened to the shaft and the other riding loosely
upon it and connected to the fly wheel governor, by which it may be
turned forward or back as the load requires. The three points of
lead, or admission and exhaust and compression, are fixed and
independent of the changes and cut off. The motion of the main
eccentric is given to a rocker arm, the pivot of which is at the
bottom, and from the upper end the valve rod transfers the motion
to the valve without reversing the motion, as is done sometimes in
the slide valve to overcome the effects of the angularity of the
connecting rod. The action of the rocker arm, therefore, so far as
the main valve in the Buckeye is concerned, is no different than
that which would occur if no rocker arm intervened. The motion of
the cut off eccentric, through its eccentric rod, is given to a
rocker rocking in a bearing in the center of the main rocker arm
(see Fig. 6). The motion of this eccentric is reversed, so far as
the cut off valve is concerned, and when the cut off eccentric is
moving forward, the cut off valve is being pushed back. The main
valve rod is hollow, and the cut off valve rod passes through
it.

FIG. 6

The cut off eccentric can be placed in any position to cause it
to cut off as desired, and by drawing the valve forward, by
increasing the angular advance of the eccentric, the cut off valve
is caused to reach and cover the steam passage in the main valve
earlier in the stroke. Instead of being ahead of the crank, the
main eccentric in this arrangement follows the crank, on account of
the exhaust and steam edges being exactly opposite from those in
the ordinary slide. What is the steam edge of the common slide is
in this the exhaust edge, and what is the exhaust edge in the
common valve is the steam edge in this one. The valve, therefore,
must be moved in the opposite direction from what is ordinarily the
case, the main eccentric being not 90 deg. behind the crank. It has
a rapid and full opening just the same, for it is at this point
behind the crank, or ahead of it, that the eccentric gives to the
valve its quickest movement, or between the eccentric dead centers.
The cut off eccentric is considerably ahead of the main eccentric,
and about even with the crank. If it was not for the reversal of
motion of the cut off valve through the rocker arm this eccentric
would be about in line with the crank, but on the other end. The
movement of the cut off valve, therefore, at the time of port
opening is very little, being about on its dead center, passing
which, it immediately commences to close.

The object of the peculiar construction of the rocker arm, and
the pivot for the cut off rocker being placed thereon, is to
provide equal travel on the back of the main valve, no matter what
the cut off. I have already explained, in connection with the slide
valve, that advancing the eccentric does not change the movement of
the valve on its seat, but simply its relation to the movement of
the piston. You will see that this is unchanged as using the main
valve as a seat or any other seat. If the main valve was to remain
stationary, and only the cut off valve to be operated by its
eccentric, the movement of this cut off valve on a certain plane
would be the same for all positions of the eccentric.

Moving the main slide does not affect the matter in any way, for
it moves at the same time the pivot of the cut off, and while the
cut off seat has assumed a different position with reference to the
engine, it is still as though stationary so far as the cut off
valve is concerned. This is the object of this peculiar
construction, and not, as some engineers suppose, simply to make an
odd way of doing things. And the object of it all is to give at all
cut offs the same amount of travel, so that there might be no
unequal wear to bring about a leak, to prevent which a perfect
balancing has been sacrificed.

Referring to the valve and this engine as to how it will satisfy
our requirements of a perfect valve gear, we find that the first
requirement of a rapid and full opening is met, in that the opening
occurs when the main eccentric is moving very rapidly, yet not its
fastest, and while this opening will be very satisfactory, it is
not so rapid an opening as is obtained in some other forms of
valves and valve gears, but this could be overcome very readily by
increasing the lead a trifle, and in my experience with these
engines I find that the practice is very general by engineers and
by builders themselves to give them a considerable amount of lead.
As to the second requirement, the maintenance of initial pressure
until cut off, giving a straight steam line, cards from this engine
will not be found to show that the engine satisfies this
requirement, and for this reason, that the cut-off valve commences
to close the port immediately after the piston commences to move.
The cut off eccentric you will remember is set to move with the
crank or very nearly so, and the lighter the load, the greater will
this fact appear. For the lightest loads the governor places the
eccentric in advance of the crank, so that the cut off valve will
commence to close the port before steam is admitted by the main
valve to the engine. Now, the later the cut off, the less will this
wire drawing appear at first, and the shorter the cut off, the
amount of wire drawing increases sensibly. The operation of the
valve, therefore, in this particular, cannot be considered as
meeting our requirement that the port shall be held open full width
until ready to be closed. Many men claim for this engine that the
closing occurs when the cut off eccentric is moving its fastest.
This is a fact, and if we consider the point of cut off only to be
the point of absolute cut off, the cut off must be instantaneous,
for there is an instantaneous point where the cut off is final only
to be considered. The reasoning applied here would hold good also
to a less extent on the slide valve, but is not the point of
absolute cut off. We want to note how long it is from the time the
valve commences to close at all until finally closed, and, as I
have shown you, this is considerable in this engine.

Referring to the point of cut off finally, it is determined upon
by a governor of the fly wheel type. The eccentric is loose about
the shaft, and arms projecting therefrom are connected by other
arms to the extremity of an arm upon which is mounted a weight, and
which is attached to the spokes of the fly wheel, or special
governor wheel in this case, and which is fastened to the crank
shaft. As the speed increases through throwing off a portion of the
load the governor weights fly out, and this movement is transferred
through the lever connections to the eccentric, causing it to be
turned ahead, and the manner hastening the movement of the cut off
valve on its seat and causing it to reach and cover the edge of the
steam port earlier in the stroke. This engine was the pioneer in
governors of this character, the advantage being, in addition to
its necessity for the work of turning the eccentric ahead or back,
that the liability of the engine to run away, as very often happens
from the breaking of the governor belt or a similar cause, was not
possible.

The cut off valve has a travel considerably beyond the edge of
the steam passage after the valve is closed, and this has one
advantage, that the valve is less liable to leak, and to this must
be added the loss from the friction of this moving valve, and
moving too in opposition to the main valve. In our perfect valve,
as we outlined it, the valve does not move after the port is
closed. The exhausting functions of the valve are very good, giving
a quick opening and a full opening, because this opening occurs
when the eccentric is moving its fastest. The engine also possesses
a distinct advantage in having remarkably small clearance spaces.
The length of the steam passage is very small in comparison with
any form of engine, and having but two ports instead of four, as in
the Corliss and four valve type.

In these there must be included in the clearance, that to the
exhaust port as well as the steam port, adding a considerable
amount where the piston comes close to the head. As the engines
leave the maker’s hand the engines are provided with a considerable
amount of lap to give plenty of compression, but are, of course,
capable of having more added to increase compression, or some
planed off to decrease it.

One of the peculiar things about this engine is the failure to
realize anywhere near boiler pressure, noticeable in every case
that has come under my notice. The considerable lead gives it for
an instant, but it soon falls away, indicating the steam chest
pressure only by a peak at the junction of the admission and steam
lines. This is probably due to the fact that the cut off valve
commences closing the steam passage so soon after steam is
admitted, and in this particular does not satisfy the requirements
of a perfect valve. There is this about the engine, that above all
others of this type there has come under my notice fewer engines of
this type with a maladjustment of valves from tampering by
incompetent engineers.

FIRING POINTS OF VARIOUS
EXPLOSIVES.

An apparatus, devised by Horsley, was used, which consisted of
an iron stand with a ring support holding a hemispherical iron
vessel, in which paraffin or tin was put. Above this was another
movable support, from which a thermometer was suspended and so
adjusted that its bulb was immersed in molten material in the iron
vessel. A thin copper cartridge case, 5/8 in. in diameter and
1-5/16 in. long, was suspended over the bath by means of a
triangle, so that the end of the case was 1 in. below the surface
of the liquid. On beginning the experiment the material in the bath
was heated to just above the melting point, the thermometer was
inserted in it, and a minute quantity of the explosive was placed
in the bottom of the cartridge case. The temperature marked by the
thermometer was noted as the initial temperature, the
cartridge case containing the explosive was inserted in the bath,
and the temperature quickly raised until the explosive flashed off
or exploded, when the temperature marked by the thermometer was
again noted as the firing point. The tables given show the
results of about six experiments with each explosive. The initial
temperatures range from 65° to 280° C. in some cases, but
as the firing points remained fairly constant, only the extremes of
the latter are quoted in the following table:

—C.E. Munroe, J. Amer. Chem. Soc.

STATION FOR TESTING
AGRICULTURAL MACHINES.

The minister of agriculture has recently established a special
laboratory for testing agricultural materiel. This
establishment, which is as yet but little known, is destined to
render the greatest services to manufacturers and cultivators.

In fact, agriculture now has recourse to physics and mechanics
as well as to chemistry. Now, although there were agricultural
laboratories whose mission it was to fix the choice of the
cultivator upon such or such a seed or fertilizer, there was no
official establishment designed to inform him as to the value of
machines, the models of which are often very numerous.
Chemical advice was to be had, but mechanical advice
was wanting. It is such a want that has just been supplied. Upon
the report presented by Mr. Tisserand, director of agriculture, a
ministerial decree of the 24th of January, 1888, ordered the
establishment of an experimental station. Mr. Ringelmann, professor
of rural engineering at the school of Grignon, was put in charge of
the installation of it, and was appointed its director. He
immediately began to look around for a site, and on the 17th of
December, 1888, the Municipal Council of Paris, taking into
consideration the value of such an establishment to the city’s
industries, decided that a plot of ground of an area of 3,309
square meters, situated on Jenner Street, should be put at the
disposal of the minister of agriculture for fifteen years for the
establishment thereon of a trial station. This land, bordering on a
very wide street and easy of access, opposite the municipal
buildings, offers, through its area, its situation, and its
neigborhood, indisputable advantages. A fence 70 meters in extent
surrounds the station. An iron gate opens upon a paved path that
ends at the station.

The year 1889 was devoted to the installation, and the station
is now in full operation. The tests that can be made here are many,
and concern all kinds of apparatus, even those connected with the
electric lighting that the agriculturist may employ to facilitate
his exploitation. However, the tests that are oftenest made are (1)
of rotary apparatus, such as mills, thrashing machines, etc.; (2)
of traction machines, such as wagons, carts, plows, etc.; and (3)
of lifting apparatus. It is possible, also, to make experiments on
the resistance of materials.

The experimental hall contains a 7 horse power gas motor,
dynamometers with automatic registering apparatus, counters,
balances, etc. A small machine shop contains a lathe, a forge, a
drilling machine, etc. The main shaft is 12 meters in length and is
7 centimeters in diameter. It is supported at a distance of one
meter from the floor by four pillow blocks, and is formed of three
sections united by movable coupling boxes. Out of these 12 meters,
9 are in the hall and 3 extend beyond the hall to an annex, 14
meters in length and 4 in width, in which tests are made of
machines whose operation creates dust. When the machines to be
tested require more than the power of seven horses that the motor
gives, the persons interested furnish a movable engine, which,
placed under the annex, actuates the driving shaft. Alongside of
the main building there is a ring for experimenting upon machines
actuated by a horse whim. There will soon be erected in the center
of the grounds an 18 meter tower for experiments on pumps.
Platforms spaced 5 meters apart, a crane at the top, and some
gauging apparatus will complete this hydraulic installation.

The equipment of the hall is very complete, and is fitted for
all kinds of experiments.

STATION FOR TESTING AGRICULTURAL
MACHINES—DYNAMOMETER FOR TESTING ROTARY MACHINES.

The tests of rotary machines are made by means of a dynamometer
(see figure). Two fast pulleys and one loose pulley are interposed
between the machine to be tested and the motor. The pulley
connected with the motor carries along the one connected with the
machine, through the intermedium of spring plates, whose strength
varies with the nature of the apparatus to be tested. The greater
or less elongation of these plates gives the tangential stress
exerted by the driving pulley to carry along the pulley that
actuates the machine to be tested. This elongation is registered by
means of a pencil connected with the spring plates, and which draws
a diagram upon a sheet of paper. At the same time, a special
totalizer gives the stress in kilogrammeters. Besides, the pulley
shaft actuates a revolution counter, and a clock measures the time
employed in the experiment. In order to obtain a simultaneous
starting and stopping point for all these apparatus, they are
connected electrically, and, through the maneuver of a commutator,
are all controlled at once. The electric current is furnished by
two series of bichromate batteries.

The tests of traction machines are effected by means of a
three-wheeled vehicle carrying a dynamometer. The front wheel is
capable of turning freely in the horizontal plane, and the
dynamometer is mounted upon a frame provided with a screw that
permits of regulating its position according to the slope of the
ground. The method of suspension of the dynamometer allows it to
take automatically the inclination of the line of traction without
any torsion of the plates. There are two models of this vehicle,
one designed to be drawn by a man, and the other by a horse.

The station is provided, in addition, with registering pressure
gauges, a large double dynamometric indicator, a counter of
electricity, balances of precision, etc.

An apparatus designed for measuring the rendering of presses is
now in course of construction.

Although the station has been in operation only from the 1st of
January, twenty-five machines have already been presented to be
tested.—Extract from Le Genie Civil.

WATER SOFTENING AND PURIFYING
APPARATUS.

We have recently had brought under our notice a system of water
and sewage purification which appears to possess several
substantial advantages. Chief among these are simplicity in
construction and operation, economy in first cost and working and
efficiency in action. This system is the invention of Messrs. Slack
& Brownlow, of Canning Works, Upper Medlock Street, Manchester,
and the apparatus adopted in carrying it out is here illustrated.
It consists of an iron cylindrical tank having inside a series of
plates arranged in a spiral direction around a fixed center, and
sloping downward at a considerable angle outward. The water to be
purified and softened flows through the large inlet tube to the
bottom, mixing on its way with the necessary chemicals, and
entering the apparatus at the bottom, rises to the top, passing
spirally round the whole circumference, and depositing on the
plates all solids and impurities.

All that is needed in the way of attention, even when dealing
with sewage, or the most polluted waters, is stated to be the
mixing in the small tanks the necessary chemical reagents, at the
commencement of the working day; and at the close of the day the
opening of the mud cocks shown in our engraving, to remove the
collected deposit upon the plates. For the past six months this
system has been in operation at a dye works in Manchester,
successfully purifying and softening the foul waters of the river
Medlock. It is stated that 84,000 gallons per day can be easily
purified by an apparatus 7 feet in diameter. The chemicals used are
chiefly lime, soda, and alumina, and the cost of treatment is
stated to vary from a farthing to twopence per 1,000 gallons,
according to the degree of impurity of the water or sewage
treated.

The results of working at Manchester show that all the visible
filth is removed from the Medlock’s inky waters, besides which the
hardness of the water is reduced to about 6° from a normal
condition of about 30°. The effluent is fit for all the varied
uses of a dye works, and is stated to be perfectly capable of
sustaining fish life. With results such as these the system should
have a promising future before it in respect of sewage treatment,
as well as the purification and softening of water generally for
industrial and manufacturing purposes.—Iron.

WATER SOFTENING AND PURIFYING APPARATUS.

THE TRISECTION OF ANY ANGLE.

By FREDERIC R. HONEY, Ph.B., Yale University.

The following analysis shows that with the aid of an hyperbola
any arc, and therefore any angle, may be trisected.

If the reader should not care to follow the analytical work, the
construction is described in the last paragraph—referring to
Fig. II.

Let a b c d (Fig. I.) be the arc subtending a given
angle. Draw the chord a d and bisect it at o. Through
o draw e f perpendicular to a d.

We wish to find the locus of a point c whose distance
from a given straight line e f is one-half the distance from
a given point d.

In order to write the equation of this curve, refer it to the
co-ordinate axes a d (axis of X) and e f (axis of Y),
intersecting at the origin o.

This is the equation of an hyperbola whose center is on the axis
of abscisses. In order to determine the position of the center,
eliminate the x term, and find the distance from the origin o to a
new origin o’.

Substituting this value of x in equation I.

In this equation the x’ terms should disappear.

That is, the distance from the origin o to the new origin
or the center of the hyperbola o’ is equal to one-third of
the distance from o to d; and the minus sign
indicates that the measurement should be laid off to the left of
the origin o. Substituting this value of E in equation II.,
and omitting accents—

We have

This is the equation of an hyperbola referred to its center
o’ as the origin of co-ordinates. To write it in the
ordinary form, that is in terms of the transverse and conjugate
axes, multiply each term by C, i.e.,

When in this form the product of the coefficients of the
x² and y² terms should be equal to the
remaining term.

That is

And equation III. becomes:

(4D² / 9) y² – (4D² / 3) x² =
16D⁴ / 27

The semi-transverse axis = √4D² /9 = 2D / 3

The semi-conjugate axis = √4D² / 3 = 2D /
√3

Since the distance from the center of the curve to either focus
is equal to the square root of the sum of the squares of the
semi-axes, the distance from o‘ to either focus

= √4D²/9 + 4D²/ 3 = 4D /
3

We can therefore make the following construction (Fig. II.) Draw
a d the chord of the arc a c d. Trisect a d at
o’ and k. Produce d a to l, making a
l = a o’ = o’ k = k d. With a k as
a transverse axis, and l and d as foci, construct the
branch of the hyperbola k c c’ c”, which will intersect all
arcs having the common chord a d at c, c’, c”, etc.,
making the arcs c d, c’ d, c” d, etc.,
respectively, equal to one-third of the arcs a c d, a c’
d, a c” d, etc.

TEST CARD HINTS.

By Dr. F. OGDEN STOUT.

I know it is the custom with a great many if not the majority of
opticians to fit a customer without knowing whether he has
presbyopia, hypermetropia, or any of the other errors of
refraction. Their method is first to try a convex, and if this does
not improve, a concave, etc., until the proper one is found. This,
of course, amounts to the same thing if the right glass is found.
But in practice it will be found both time saving and more
satisfactory to first decide with what error you have to deal. It
is very simple, and, where you have no other means of diagnosing
(such as the ophthalmoscope), it does away with the necessity of
trying so many lenses before the proper one is found. You should
have a distance test card placed at a distance of twenty feet from
the person you are examining, and in a good light.

A distance test card consists of letters of various sizes which
it has been found can be seen at certain distances by people with
good vision. Thus the largest letter is marked with a cc, meaning
that this should be seen at two hundred feet, and another line, XX,
at twenty feet, which is the proper distance for testing vision for
distance, for the reason that a normal eye is at rest when looking
at any object twenty feet from it or beyond, and the rays coming
from it are parallel and come to a focus on the retina. You must
also have a near vision test card with lines that should be seen by
a normal eye from ten to seventy-two inches, and a card of
radiating lines for astigmatism. With this preparation you are
ready to proceed. To illustrate, the first customer comes and tells
you that up to six months ago he had very good vision, but he finds
now that, especially at night, he has trouble in reading or
writing, and that he finds he can see better a little farther away.
His head aches and eyes smart. You will of course say that this is
a very simple case. It must be old sight (presbyopia). Probably it
is if he is old enough (45), but you must prove this for yourself,
without asking his age, which is embarrassing in the case of a
lady. If you direct him to the distance card twenty feet away, and
find that he can see every one down to and including the one marked
XX, his vision is up to the standard for distance, and you know
that he can have no astigmatism worth correcting, nor any near
sight, as both of these affect vision for distance, but he may have
far sight or old sight or both combined. You must find which it
is.

If, while he is still looking at the twenty-foot line, you place
in front of the eyes a weak convex and he tells you he sees just as
well with as without, it proves the existence of far-sight or
hypermetropia, and the strongest convex that still leaves vision as
good for distance as without any, corrects the manifest. But if the
weak convex blurs it, it shows that there is some defect in
focusing, if the near vision is below normal. You therefore know
that you have a case of old sight or presbyopia, requiring the
weakest convex to correct it, that will enable your customer to see
the finest line on the near card at the required distance.

The next customer that comes to be fitted with glasses can only
see the line marked XL on the distance card at 20 feet or about
one-half of what he should see, which leads you to think that there
is no far sight, for vision for distance is good except in very
high degrees of this error. Nor can there be old-sight, for vision
for distance is good in old-sight until after the fifty-fifth year,
but it can be near sight (myopia) or astigmatism, or both. We next
try the near card and find that even the finest line can be seen
clearly if held sufficiently close to the eyes. We now know that
this is a case of near sight, and we must fit them with glasses for
distance. The weakest concave that will enable him to see the line
that should be seen on the distance card at 20 feet is the proper
one to give him for use.—The Optician.

CHARLES GOODYEAR.

CHARLES GOODYEAR was born in New Haven, December 29, 1800. He
was the son of Amasa Goodyear, and the eldest among six children.
His father was quite proud of being a descendant of Stephen
Goodyear, one of the founders of the colony of New Haven in
1638.

Amasa Goodyear owned a little farm on the neck of land in New
Haven which is now known as Oyster Point, and it was here that
Charles spent the earliest years of his life. When, however, he was
quite young, his father secured an interest in a patent for the
manufacture of ivory buttons, and looking for a convenient location
for a small mill, settled at Naugatuck, Conn., where he made use of
the valuable water power that is there. Aside from his
manufacturing, the elder Goodyear ran a farm, and between the two
lines of industry kept young Charles pretty busy.

In 1816, Charles left his home and went to Philadelphia to learn
the hardware business. He worked at this very industriously until
he was twenty-one years old, and then, returning to Connecticut,
entered into partnership with his father at the old stand in
Naugatuck, where they manufactured not only ivory and metal
buttons, but a variety of agricultural implements, which were just
beginning to be appreciated by the farmers. In August of 1824 he
was united in marriage with Clarissa Beecher, a woman of remarkable
strength of character and kindness of disposition, and one who in
after years was of the greatest assistance to the impulsive
inventor. Two years later he removed again to Philadelphia, and
there opened a hardware store. His specialties were the valuable
agricultural implements that his firm had been manufacturing, and
after the first distrust of home made goods had worn away—for
all agricultural implements were imported from England at that
time—he found himself established at the head of a successful
business.

This continued to increase until it seemed but a question of a
few years until he would be a very wealthy man. Between 1829 and
1830 he suddenly broke down in health, being troubled with
dyspepsia. At the same time came the failure of a number of
business houses that seriously embarrassed his firm. They struggled
on, however, for some time, but were finally obliged to fail. The
ten years that followed this were full of the bitterest struggles
and trials to Goodyear. Under the law that then existed he was
imprisoned time after time for debts, even while he was trying to
perfect inventions that should pay off his indebtedness.

Between the years 1831 and 1832 he began to hear about gum
elastic and very carefully examined every article that appeared in
the newspapers relative to this new material. The Roxbury Rubber
Company, of Boston, had been for some time experimenting with the
gum, and believing that they had found means for manufacturing
goods from it, had a large plant and were sending their goods all
over the country. It was some of their goods that first attracted
his attention. Soon after this Goodyear visited New York, and went
at once to the store of the Roxbury Rubber Company. While there, he
examined with considerable care some of their life preservers, and
it struck him that the tube used for inflation was not very
perfect. He, therefore, on his return to Philadelphia, made some
tubes and brought them down to New York and showed them to the
manager of the Roxbury Rubber Company.

This gentlemen was so pleased with the ingenuity that Goodyear
had shown in manufacturing these tubes, that he talked very freely
with him and confessed to him that the business was on the verge of
ruin, that the goods had to be tested for a year before they could
tell whether they were perfect or not, and to their surprise,
thousands of dollars worth of goods that they had supposed were all
right were coming back to them, the gum having rotted and made them
so offensive that it was necessary to bury them in the ground to
get them out of the way.

Goodyear at once made up his mind to experiment on this gum and
see if he could not overcome its stickiness.

He, therefore, returned to Philadelphia, and, as usual, met a
creditor, who had him arrested and thrown into prison. While there,
he tried his first experiments with India rubber. The gum was very
cheap then, and by heating it and working it in his hands, he
managed to incorporate in it a certain amount of magnesia which
produced a beautiful white compound and appeared to take away the
stickiness.

He therefore thought he had discovered the secret, and through
the kindness of friends was put in the way of further perfecting
his invention at a little place in New Haven. The first thing that
he made here was shoes, and he used his own house for grinding
room, calender room, and vulcanizing department, and his wife and
children helped to make up the goods. His compound at this time was
India rubber, lampblack, and magnesia, the whole dissolved in
turpentine and spread upon the flannel cloth which served as the
lining for the shoes. It was not long, however, before he
discovered that the gum, even treated this way, became sticky, and
then those who had supplied the money for the furtherance of these
experiments, completely discouraged, made up their minds that they
could go no further, and so told the inventor.

CHARLES GOODYEAR.

He, however, had no mind to stop here in his experiments, but,
selling his furniture and placing his family in a quiet boarding
place, he went to New York, and there, in an attic, helped by a
friendly druggist, continued his experiments. His next step in this
line was to compound the rubber with magnesia and then boil it in
quicklime and water. This appeared to really solve the problem, and
he made some beautiful goods. At once it was noised abroad that
India rubber had been so treated that it lost its stickiness, and
he received medals and testimonials and seemed on the high road to
success, till one day he noticed that a drop of weak acid, falling
on the cloth, neutralized the alkali, and immediately the rubber
was soft again. To see this, with his knowledge of what rubber
should do, proved to him at once that his process was not a
successful one. He therefore continued experimenting, and after
preparing his mixtures in his attic in New York, would walk three
miles to the mill of a Mr. Pike, at Greenwich village, and there
try various experiments.

In the line of these, he discovered that rubber, dipped in
nitric acid, formed a surface cure, and he made a great many goods
with this acid cure which were spoken of, and which even received a
letter of commendation from Andrew Jackson.

The constant and varied experiments that Goodyear went through
with affected his health more or less, and at one time he came very
near being suffocated by gas generated in his laboratory. That he
did not die then everybody knows, but he was thrown then into a
fever by the accident and came very near losing his life.

It was there that he formed an acquaintance with Dr. Bradshaw,
who was very much pleased with the samples of rubber goods that he
saw in Goodyear’s room, and when the doctor went to Europe he took
them with him, where they attracted a great deal of attention, but
beyond that nothing was done about them. Now that he appeared to
have success, he found no difficulty in obtaining a partner, and
together the two gentlemen fitted up a factory and began to make
clothing, life preservers, rubber shoes, and a great variety of
rubber goods. They also had a large factory, with special
machinery, built at Staten Island, where he removed his family and
again had a home of his own. Just about this time, when everything
looked bright, the great panic of 1836-1837 came, and swept away
the entire fortune of his associate and left Goodyear without a
cent, and no means of earning one.

His next move was to go to Boston, where he became acquainted
with J. Haskins, of the Roxbury Rubber Company, and found in him a
firm friend, who loaned him money and stood by him when no one
would have anything to do with the visionary inventor. Mr. Chaffee
was also exceedingly kind and ever ready to lend a listening ear to
his plans, and to also assist him in a pecuniary way. It was about
this time that it occurred to Mr. Chaffee that much of the trouble
that they had experienced in working India rubber might come from
the solvent that was used. He therefore invented a huge machine for
doing the mixing by mechanical means. The goods that were made in
this way were beautiful to look at, and it appeared, as it had
before, that all difficulties were overcome.

Goodyear discovered a new method for making rubber shoes and got
a patent on it, which he sold to the Providence Company, in Rhode
Island.

The secret of making the rubber so that it would stand heat and
cold and acids, however, had not been discovered, and the goods
were constantly growing sticky and decomposing and being
returned.

In 1838 he, for the first time, met Nathaniel Hayward, who was
then running a factory in Woburn. Some time after this Goodyear
himself moved to Woburn, all the time continuing his experiments.
He was very much interested in Hayward’s sulphur experiments for
drying rubber, but it appears that neither of them at that time
appreciated the fact that it needed heat to make the sulphur
combine with the rubber and to vulcanize it.

The circumstances attending the discovery of his celebrated
process is thus described by Mr. Goodyear himself in his book, “Gum
Elastic.” It will be observed that he makes use of the third person
in all references to himself:

“In the summer of 1838 he became acquainted with Mr. Nathaniel
Hayward, of Woburn, Mass., who had been employed as the foreman of
the Eagle Company at Woburn, where he had made use of sulphur by
impregnating the solvent with it. It was through him that the
writer (Charles Goodyear, who makes use all through his book of the
third person) received the first knowledge of the use of sulphur as
a drier of gum elastic.

“Mr. Hayward was left in possession of the factory which was
abandoned by the Eagle Company. Soon after this it was occupied by
the writer, who employed him for the purpose of manufacturing life
preservers and other articles by the acid gas process. At this
period he made many novel and useful applications of this
substance. Among other fancy articles he had newspapers printed on
the gum elastic drapery, and the improvement began to be highly
appreciated. He therefore now entered, as he thought, upon a
successful career for the future. A far different result awaited
him.

“It was supposed by others as well as himself that a change was
wrought through the mass of the goods acted upon by the acid gas,
and that the whole body of the article was made better than the
native gum. The surface of the goods really was so, but owing to
the eventual decomposition of the goods beneath the surface, the
process was pronounced by the public a complete failure. Thus
instead of realizing the large fortune which by all acquainted with
his prospects was considered certain, his whole invention would not
bring him a week’s living.

“He was obliged for the want of means to discontinue
manufacturing, and Mr. Hayward left his employment. The inventor
now applied himself alone, with unabated ardor and diligence, to
detect the cause of his misfortune and if possible to retrieve the
lost reputation of his invention. On one occasion he made some
experiments to ascertain the effect of heat upon the same compound
that had decomposed in the articles previously manufactured, and
was surprised to find that the specimen, being carelessly brought
in contact with a hot stove, charred like leather. He endeavored to
call the attention of his brother as well as some other individuals
who were present, and who were acquainted with the manufacture of
gum elastic, to this effect as remarkable and unlike any before
known, since gum elastic always melted when exposed to a high
degree of heat. The occurrence did not at the time appear to them
to be worthy of notice. It was considered as one of the frequent
appeals that he was in the habit of making in behalf of some new
experiment. He, however, directly inferred that if the process of
charring could be stopped at the right point, it might divest the
gum of its native adhesiveness throughout, which would make it
better than the native gum.

“He made another trial of heating a similar fabric, before an
open fire. The same effect, that of charring the gum, followed, but
there were further and very satisfactory indications of ultimate
success in producing the desired result, as upon the edge of the
charred portions of the fabric there appeared a line, or border,
that was not charred, but perfectly cured.

“These facts have been stated precisely as they occurred in
reference to the acid gas, as well as the vulcanizing process.

“The incidents attending the discovery of both have a strong
resemblance, so much so they may be considered parallel cases. It
being now known that the results of the vulcanizing process are
produced by means and in a manner which would not have been
anticipated from any reasoning on the subject, and that they have
not yet been satisfactorily accounted for, it has been sometimes
asked, how the inventor came to make the discovery? The answer has
already been given. It may be added that he was many years seeking
to accomplish this object, and that he allowed nothing to escape
his notice that related to the subject. Like the falling of an
apple, it was suggestive of an important fact to one whose mind was
previously prepared to draw an inference from any occurrence which
might favor the object of his research. While the inventor admits
that these discoveries were not the results of scientific chemical
investigations, he is not willing to admit that they were the
result of what is commonly termed accident; he claims them to
be the result of the closest application and observation.

“The discoloring and charring of the specimens proved nothing
and discovered nothing of value, but quite the contrary, for in the
first instance, as stated in the acid gas improvement, the specimen
acted upon was thrown away as worthless and left for some time; in
the latter instance, the specimen that was charred was in like
manner disregarded by others.

“It may, therefore, be considered as one of those cases where
the leading of the Creator providentially aids his creatures, by
what are termed ‘accidents,’ to attain those things which are not
attainable by the powers of reasoning he has conferred on
them.”

Now that Goodyear was sure that he had the key to the intricate
puzzle that he had worked over for so many years, he began at once
to tell his friends about it and to try to secure capital, but they
had listened to their sorrow so many times that his efforts were
futile. For a number of years be struggled and experimented and
worked along in a small way, his family suffering with himself the
pangs of the extremest poverty. At last he went to New York and
showed some of his samples to William Ryder, who, with his brother
Emory, at once appreciated the value of the discovery and started
in to manufacturing. Even here Goodyear’s bad luck seemed to follow
him, for the Ryder Bros. failed and it was impossible to continue
the business.

He had, however, started a small factory at Springfield, Mass.,
and his brother-in-law, Mr. De Forest, who was a wealthy woolen
manufacturer, took Ryder’s place, and the work of making the
invention practical was continued. In 1844 it was so far perfected
that Goodyear felt it safe to take out a patent. The factory at
Springfield was run by his brothers, Nelson and Henry.

In 1843 Henry started one in Naugatuck, and in 1844 introduced
mechanical mixing in place of the mixture by the use of
solvents.

In the year 1852 Goodyear went to Europe, a trip that he had
long planned, and saw Hancock, then in the employ of Charles
Macintosh & Co. Hancock admitted in evidence that the first
piece of vulcanized rubber he ever saw came from America, but
claimed to have reinvented vulcanization and secured patents in
Great Britain, but it is a remarkable fact that Charles
Goodyear’s French patent was the first publication in Europe of
this discovery.

In 1852 a French company were licensed by Mr. Goodyear to make
shoes, and a great deal of interest was felt in the new business.
In 1855 the French emperor gave to Charles Goodyear the grand medal
of honor and decorated him with the cross of the legion of honor in
recognition of his services as a public benefactor, but the French
courts subsequently set aside his French patents on the ground of
the importation of vulcanized goods from America by licenses under
the United States patents. He died July 1, 1860, at the Fifth
Avenue Hotel, New York City.—India Rubber World.

[Continued from SUPPLEMENT, No. 786, page
12558.]

THE ELECTROMAGNET.¹

By Professor SILVANUS P. THOMPSON, D.Sc., B.A., M.I.E.E.

III.

RESEARCHES OF PROFESSOR HUGHES.

FIG. 51.—HUGHES’ ELECTROMAGNET.

His object was to find out the best form of electromagnet, the
best distance between the poles, and the best form of armature for
the rapid work required in Hughes’ printing telegraphs. One word
about Hughes’ magnets. This diagram (Fig. 51) shows the form of the
well known Hughes’ electromagnet. I feel almost ashamed to say
those words “well known,” because on the Continent everybody knows
what you mean by a Hughes’ electromagnet. In England scarcely
anyone knows what you mean. Englishmen do not even know that
Professor Hughes has invented a special form of electromagnet.
Hughes’ special form is this: A permanent steel magnet, generally a
compound one, having soft iron pole pieces, and a couple of coils
on the pole pieces only. As I have to speak of Hughes’ special
contrivance among the mechanisms that will occupy our attention
later on, I only now refer to this magnet in one particular. If you
wish a magnet to work rapidly, you will secure the most rapid
action, not when the coils are distributed all along, but when they
are heaped up near, not necessarily entirely on, the poles. Hughes
made a number of researches to find out what the right length and
thickness of these pole pieces should be. It was found an advantage
not to use too thin pole pieces, otherwise the magnetism from the
permanent magnet did not pass through the iron without considerable
reluctance, being choked by insufficiency of section: also not to
use too thick pieces, otherwise they presented too much surface for
leakage across from one to the other. Eventually a particular
length was settled upon, in proportion about six times the
diameter, or rather longer. In the further researches that Hughes
made he used a magnet of shorter form, not shown here, more like
those employed in relays, and with an armature from 2 to 3
millimeters thick, 1 centimeter wide and 5 centimeters long. The
poles were turned over at the top toward one another. Hughes tried
whether there was any advantage in making those poles approach one
another, and whether there was any advantage in having as long an
armature as 5 centimeters. He tried all the different kinds, and
plotted out the results of observations in curves, which could be
compared and studied. His object was to ascertain the conditions
which would give the strongest pull, not with a steady current, but
with such currents as were required for operating his printing
telegraph instruments; currents which lasted but one to twenty
hundredths of a second. He found it was decidedly an advantage to
shorten the length of the armature, so that it did not protrude far
over the poles. In fact, he got a sufficient magnetic circuit to
secure all the attractive power that he needed, without allowing as
much chance of leakage as there would have been had the armature
extended a longer distance over the poles. He also tried various
forms of armature having very various cross sections.

POSITION AND FORM OF ARMATURE.

In one of Du Moncel’s papers on electromagnets² you will also find a discussion on
armatures, and the best forms for working in different positions.
Among other things in Du Moncel you will find this paradox: that
whereas using a horseshoe magnet with fat poles, and a flat piece
of soft iron for armature, it sticks on far tighter when put on
edgeways; on the other hand, if you are going to work at a
distance, across air, the attraction is far greater when it is set
flatways. I explained the advantage of narrowing the surfaces of
contact by the law of traction, B², coming in. Why
should we have for action at a distance the greater advantage from
placing the armature flatway to the poles? It is simply that you
thereby reduce the reluctance offered by the air gap to the flow of
the magnetic lines. Du Moncel also tried the difference between
round armatures and flat ones, and found that a cylindrical
armature was only attracted about half as strongly as a prismatic
armature having the same surface when at the same distance. Let us
examine this fact in the light of the magnetic circuit. The poles
are flat. You have at a certain distance away a round armature;
there is a certain distance between its nearest side and the polar
surfaces. If you have at the same distance away a flat armature
having the same surface, and, therefore, about the same tendency to
leak, why do you get a greater pull in this case than in that? I
think it is clear that if they are at the same distance away,
giving the same range of motion, there is a greater magnetic
reluctance in the case of the round armature, although there is the
same periphery, because, though the nearest part of the surface is
at the prescribed distance, the rest of the under surface is
farther away; so that the gain found in substituting an armature
with a flat surface is a gain resulting from the diminution in the
resistance offered by the air gap.

POLE PIECES ON HORSESHOE MAGNETS.

Another of Du Moncel’s researches³ relates
to the effect of polar projections or shoes—movable pole
pieces, if you like—upon a horseshoe electromagnet. The core
of this magnet was of round iron 4 centimeters in diameter, and the
parallel limbs were 10 centimeters long and 6 centimeters apart.
The shoes consisted of two flat pieces of iron slotted out at one
end, so that they could be slid along over the poles and brought
nearer together. The attraction exerted on a flat armature across
air gaps 2 millimeters thick was measured by counterpoising.
Exciting this electromagnet with a certain battery, it was found
that the attraction was greatest when the shoes were pushed to
about 15 millimeters, or about one-quarter of the interpolar
distance, apart. The numbers were as follows:

With a stronger battery the magnet without shoes had an
attraction of 885 grammes, but with the shoes 15 millimeters apart,
1,195 grammes. When one pole only was employed, the attraction,
which was 88 grammes without a shoe, was diminished by
adding a shoe to 39 grammes!

CONTRAST BETWEEN ELECTROMAGNETS AND PERMANENT MAGNETS.

Now I want particularly to ask you to guard against the idea
that all these results obtained from electromagnets are equally
applicable to permanent magnets of steel; they are not, for this
simple reason. With an electromagnet, when you put the armature
near, and make the magnetic circuit better, you not only get more
magnetic lines going through that armature, but you get more
magnetic lines going through the whole of the iron. You get more
magnetic lines round the bend when you put an armature on to the
poles, because you have a magnetic circuit of less reluctance with
the same external magnetizing power in the coils acting around it.
Therefore, in that case, you will have a greater magnetic flux all
the way round. The data obtained with the electromagnet (Fig. 42),
with the exploring coil, C, on the bend of the core, where the
armature was in contact, and when it was removed are most
significant. When the armature was present it multiplied the total
magnetic flow tenfold for weak currents and nearly threefold for
strong currents. But with a steel horseshoe, magnetized once for
all, the magnetic lines that flow around the bend of the steel are
a fixed quantity, and, however much you diminish the reluctance of
the magnetic circuit, you do not create or evoke any more. When the
armature is away the magnetic lines arch across, not at the ends of
the horseshoe only, but from its flanks; the whole of the magnetic
lines leaking somehow across the space. Where you have put the
armature on, these lines, instead of arching out into space as
freely as they did, pass for the most part along the steel limbs
and through the iron armature. You may still have a considerable
amount of leakage, but you have not made one line more go through
the bent part. You have absolutely the same number going through
the bend with the armature off as with the armature on. You do not
add to the total number by reducing the magnetic reluctance,
because you are not working under the influence of a constantly
impressed magnetizing force. By putting the armature on to a steel
horseshoe magnet you only collect the magnetic lines, you do
not multiply them. This is not a matter of conjecture. A
group of my students have been making experiments in the following
way: They took this large steel horseshoe magnet (Fig. 52), the
length of which, from end to end, through the steel, is 42½
inches. A light, narrow frame was constructed so that it could be
slipped on over the magnet, and on it were wound 30 turns of fine
wire, to serve as an exploring coil. The ends of this coil were
carried to a distant part of the laboratory, and connected to a
sensitive ballistic galvanometer. The mode of experimenting is as
follows:

The coil is slipped on over the magnet (or over its armature) to
any desired position. The armature of the magnet is placed gently
upon the poles, and time enough is allowed to elapse for the
galvanometer needle to settle to zero. The armature is then
suddenly detached. The first swing measures the change, due to
removing the armature, in the number of magnetic lines that pass
through the coil in the particular position.

FIG. 52.—EXPERIMENT WITH PERMANENT MAGNET.

I will roughly repeat the experiment before you: The spot of
light on the screen is reflected from my galvanometer at the far
end of the table. I place the exploring coil just over the pole,
and slide on the armature; then close the galvanometer circuit. Now
I detach the armature, and you observe the large swing. I shift the
exploring coil, right up to the bend; replace the armature; wait
until the spot of light is brought to rest at the zero of the
scale. Now, on detaching the armature, the movement of the spot of
light is quite imperceptible. In our careful laboratory
experiments, the effect was noticed inch by inch all along the
magnet. The effect when the exploring coil was over the bend was
not as great as 1-3000th part of the effect when the coil was hard
up to the pole. We are, therefore, justified in saying that the
number of magnetic lines in a permanently magnetized steel
horseshoe magnet is not altered by the presence or absence of the
armature.

You will have noticed that I always put on the armature gently.
It does not do to slam on the armature; every time you do so, you
knock some of the so-called permanent magnetism out of it. But you
may pull off the armature as suddenly as you like. It does the
magnet good rather than harm. There is a popular superstition that
you ought never to pull off the keeper of a magnet suddenly. On
investigation, it is found that the facts are just the other way.
You may pull off the keeper as suddenly as you like, but you should
never slam it on.

From these experimental results I pass to the special design of
electromagnets for special purposes.

ELECTROMAGNETS FOR MAXIMUM TRACTION.

These have already been dealt with in the preceding lecture; the
characteristic feature of all the forms suitable for traction being
the compact magnetic circuit.

Several times it has been proposed to increase the power of
electromagnets by constructing them with intermediate masses of
iron between the central core and the outside, between the layers
of windings. All these constructions are founded on fallacies. Such
iron is far better placed either right inside the coils or right
outside them, so that it may properly constitute a part of the
magnetic circuit. The constructions known as Camacho’s and Cance’s,
and one patented by Mr. S.A. Varley, in 1877, belonging to this
delusive order of ideas, are now entirely obsolete.

Another construction which is periodically brought forward as a
novelty is the use of iron windings of wire or strip in place of
copper winding. The lower electric conductivity of iron, as
compared with copper, makes such a construction wasteful of
exciting power. To apply equal magnetizing power by means of an
iron coil implies the expenditure of about six times as many watts
as need be expended if the coil is of copper.

ELECTROMAGNETS FOR MAXIMUM RANGE OF ATTRACTION.

We have already laid down the principle which will enable us to
design electromagnets to act at a distance. We want our magnet to
project, as it were, its force across the greatest length of air
gap. Clearly, then, such a magnet must have a very large
magnetizing power, with many ampere turns upon it, to be able to
make the required number of magnetic lines pass across the air
resistance. Also it is clear that the poles must not be too close
together for its work, otherwise the magnetic lines at one pole
will be likely to curl round and take short cuts to the other pole.
There must be a wider width between the poles than is desirable in
electromagnets for traction.

ELECTROMAGNETS OF MINIMUM WEIGHT.

In designing an apparatus to put on board a boat or a balloon,
where weight is a consideration of primary importance, there is
again a difference. There are three things that come into
play—iron, copper, and electric current. The current weighs
nothing, therefore, if you are going to sacrifice everything else
to weight, you may have comparatively little iron, but you must
have enough copper to be able to carry the electric current; and
under such circumstances you must not mind heating your wires
nearly red hot to pass the biggest possible current. Provide as
little copper as you conveniently can, sacrificing economy in that
case to the attainment of your object; but, of course, you must use
fireproof material, such as asbestos, for insulating, instead of
cotton or silk.

A USEFUL GUIDING PRINCIPLE.

In all cases of design there is one leading principle which will
be found of great assistance, namely, that a magnet always tends so
to act as though it tried to diminish the length of its magnetic
circuit. It tries to grow more compact. This is the reverse of that
which holds good with an electric current. The electric circuit
always tries to enlarge itself, so as to inclose as much space as
possible, but the magnetic circuit always tries to make itself as
compact as possible. Armatures are drawn in as near as can be, to
close up the magnetic circuit. Many two-pole electromagnets show a
tendency to bend together when the current is turned on. One form
in particular, which was devised by Ruhmkorff for the purpose of
repeating Faraday’s celebrated experiment on the magnetic rotation
of polarized light, is liable to this defect. Indeed, this form of
electromagnet is often designed very badly, the yoke being too
thin, both mechanically and magnetically, for the purpose which it
has to fulfill.

Here is a small electric bell, constructed by Wagener, of
Wiesbaden, the construction of which illustrates this principle.
The electromagnet, a horseshoe, lies horizontally; its poles are
provided with protruding curved pins of brass. Through the armature
are drilled two holes, so that it can be hung upon the two brass
pins; and when so hung up it touches the ends of the iron cores
just at one edge, being held from more perfect contact by a spring.
There is no complete gap, therefore, in the magnetic circuit. When
the current comes and applies a magnetizing power, it finds the
magnetic circuit already complete in the sense that there are no
absolute gaps. But the circuit can be bettered by tilting the
armature to bring it flat against the polar ends, that being indeed
the mode of motion. This is a most reliable and sensitive pattern
of bell.

FIG. 53.—ELECTROMAGNETIC POP-GUN.

Electromagnetic Pop-gun.—Here is another curious
illustration of the tendency to complete the magnetic circuit. Here
is a tubular electromagnet (Fig. 53), consisting of a small bobbin,
the core of which is an iron tube about two inches long. There is
nothing very unusual about it; it will stick on, as you see, to
pieces of iron when the current is turned on. It clearly is an
ordinary electromagnet in that respect. Now suppose I take a little
round rod of iron, about an inch long, and put it into the end of
the tube, what will happen when I turn on my current? In this
apparatus as it stands, the magnetic circuit consists of a short
length of iron, and then all the rest is air. The magnetic circuit
will try to complete itself, not by shortening the iron, but by
lengthening it; by pushing the piece of iron out so as to
afford more surface for leakage. That is exactly what happens; for,
as you see, when I turn on the current, the little piece of iron
shoots out and drops down. You see that little piece of iron shoot
out with considerable force. It becomes a sort of magnetic popgun.
This is an experiment which has been twice discovered. I found it
first described by Count Du Moncel, in the pages of La Lumiere
Electrique, under the name of the “pistolet electromagnetique;”
and Mr. Shelford Bidwell invented it independently. I am indebted
to him for the use of this apparatus. He gave an account of it to
the Physical Society, in 1885, but the reporter missed it, I
suppose, as there is no record in the society’s proceedings.

ELECTROMAGNETS FOR USE WITH ALTERNATING CURRENTS.

When you are designing electromagnets for use with alternating
currents, it is necessary to make a change in one respect, namely,
you must so laminate the iron that internal eddy currents shall not
occur; indeed, for all rapid-acting electromagnetic apparatus it is
a good rule that the iron must not be solid. It is not usual with
telegraphic instruments to laminate them by making up the core of
bundles of iron plates or wires, but they are often made with
tubular cores, that is to say, the cylindrical iron core is drilled
with a hole down the middle, and the tube so formed is slit with a
saw cut to prevent the circulation of currents in the substance of
the tube. Now when electromagnets are to be employed with rapidly
alternating currents, such as are used for electric lighting, the
frequency of the alternations being usually about 100 periods per
second, slitting the cores is insufficient to guard against eddy
currents; nothing short of completely laminating the cores is a
satisfactory remedy. I have here, thanks to the Brush Electric
Engineering Company, an electromagnet of the special form that is
used in the Brush arc lamp when required for the purpose of working
in an alternating current circuit. It has two bobbins that are
screwed up against the top of an iron box at the head of the lamp.
The iron slab serves as a kind of yoke to carry the magnetism
across the top. There are no fixed cores In the bobbins, which are
entered by the ends of a pair of yoked plungers. Now in the
ordinary Brush lamp for use with a steady current, the plungers are
simply two round pieces of iron tapped into a common yoke; but for
alternate current working this construction must not be used, and
instead a U-shaped double plunger is used, made up of
laminated iron, riveted together. Of course it is no novelty to use
a laminated core; that device, first used by Joule, and then by
Cowper, has been repatented rather too often during the past fifty
years to be considered as a recent invention.

The alternate rapid reversals of the magnetism in the magnetic
field of an electromagnet, when excited by alternating electric
currents, sets up eddy currents in every piece of undivided metal
within range. All frames, bobbin tubes, bobbin ends, and the like,
must be most carefully slit, otherwise they will overheat. If a
domestic flat iron is placed on the top of the poles of a properly
laminated electromagnet, supplied with alternating currents, the
flat iron is speedily heated up by the eddy currents that are
generated internally within it. The eddy currents set up by
induction in neighboring masses of metal, especially in good
conducting metals such as copper, give rise to many curious
phenomena. For example, a copper disk or copper ring placed over
the pole of a straight electromagnet so excited is violently
repelled. These remarkable phenomena have been recently
investigated by Professor Elihu Thomson, with whose beautiful and
elaborate researches we have lately been made conversant in the
pages of the technical journals. He rightly attributes many of the
repulsion phenomena to the lag in phase of the alternating currents
thus induced in the conducting metal. The electromagnetic inertia,
or self-inductive property of the electric circuit, causes the
currents to rise and fall later in time than the electromotive
forces by which they are occasioned. In all such cases the
impedance which the circuit offers is made up of two
things—resistance and inductance. Both these causes tend to
diminish the amount of current that flows, and the inductance also
tends to delay the flow.

ELECTROMAGNETS FOR QUICKEST ACTION.

I have already mentioned Hughes’ researches on the form of
electromagnet best adapted for rapid signaling. I have also
incidentally mentioned the fact that where rapidly varying currents
are employed, the strength of the electric current that a given
battery can yield is determined not so much by the resistance of
the electric circuit as by its electric inertia. It is not a very
easy task to explain precisely what happens to an electric circuit
when the current is turned on suddenly. The current does not
suddenly rise to its full value, being retarded by inertia. The
ordinary law of Ohm in its simple form no longer applies; one needs
to apply that other law which bears the name of the law of
Helmholtz, the use of which is to give us an expression, not for
the final value of the current, but for its value at any short
time, t, after the current has been turned on. The strength of the
current after a lapse of a short time, t, cannot be calculated by
the simple process of taking the electromotive force and dividing
it by the resistance, as you would calculate steady currents.

In symbols, Helmholtz’s law is:

i_t = E/R ( 1 – e^{– (R/L)t} )

In this formula i_t means the strength of the
current after the lapse of a short time t; E is the
electromotive force; R, the resistance of the whole circuit; L, its
coefficient of self-induction; and e the number 2.7183,
which is the base of the Napierian logarithms. Let us look at this
formula; in its general form it resembles Ohm’s law, but with a new
factor, namely, the expression contained within the brackets. The
factor is necessarily a fractional quantity, for it consists of
unity less a certain negative exponential, which we will presently
further consider. If the factor within brackets is a quantity less
than unity, that signifies that i_t will be less
than E ÷ R. Now the exponential of negative sign, and with
negative fractional index, is rather a troublesome thing to deal
with in a popular lecture. Our best way is to calculate some
values, and then plot it out as a curve. When once you have got it
into the form of a curve, you can begin to think about it, for the
curve gives you a mental picture of the facts that the long formula
expresses in the abstract. Accordingly we will take the following
case. Let E = 2 volts; R = 1 ohm; and let us take a relatively
large self-induction, so as to exaggerate the effect; say let L =
10 quads. This gives us the following:

In this case the value of the steady current as calculated by
Ohm’s law is 10 amperes, but Helmholtz’s law shows us that with the
great self-induction which we have assumed to be present, the
current, even at the end of 30 seconds, has only risen up to within
5 percent. of its final value; and only at the end of two minutes
has practically attained full strength. These values are set out in
the highest curve in Fig. 54, in which, however, the further
supposition is made that the number of spirals, S, in the coils of
the electromagnet is 100, so that when the current attains its full
value of 10 amperes, the full magnetizing power will be Si =
1000. It will be noticed that the curve rises from zero at first
steeply and nearly in a straight line, then bends over, and then
becomes nearly straight again, as it gradually rises to its
limiting value. The first part of the curve—that relating to
the strength of the current after very small interval of
time—is the period within which the strength of the current
is governed by inertia (i.e., the self-induction) rather than by
resistance. In reality the current is not governed either by the
self-induction or by the resistance alone, but by the ratio of the
two. This ratio is sometimes called the “time constant” of the
circuit, for it represents the time which the current takes
in that circuit to rise to a definite fraction of its final
value.

FIG. 54.—CURVES OF RISE OF CURRENTS.

This definite fraction is the fraction (e – 1)/e; or in
decimals, 0.634. All curves of rise of current are alike in general
shape, they differ only in scale, that is to say, they differ only
in the height to which they will ultimately rise, and in the time
they will take to attain this fraction of their final value.

Example (1).—Suppose E = 10; R = 200 ohms; L = 8.
The final value of the current will be 0.025 amp. or 25
milliamperes. Then the time constant will be 8 ÷ 400 =
1-50th sec.

Example (2).—The P.O. Standard “A” relay has R =
400 ohms; L = 3.25. It works with 0.5 milliampere current, and
therefore will work with 5 Daniell cells through a line of 9,600
ohms. Under these circumstances the time constant of the instrument
on short circuit is 0.0081 sec.

It will be noted that the time constant of a circuit can be
reduced either by diminishing the self-induction or by increasing
the resistance. In Fig. 54 the position of the time constant for
the top curve is shown by the vertical dotted line at 10 seconds.
The current will take 10 seconds to rise to 0.634 of its final
value. This retardation of the rise of current is simply due to the
presence of coils and electromagnets in the circuit; the current as
it grows being retarded because it has to create magnetic fields in
these coils, and so sets up opposing electromotive forces that
prevent it from growing all at once to its full strength. Many
electricians, unacquainted with Helmholtz’s law, have been in the
habit of accounting for this by saying that there is a lag in the
iron of the electromagnet cores. They tell you that an iron core
cannot be magnetized suddenly, that it takes time to acquire its
magnetism. They think it is one of the properties of iron. But we
know that the only true time lag in the magnetization of iron, that
which is properly termed “viscous hysteresis,” does not amount to
any great percentage of the whole amount of magnetization, takes
comparatively a long time to show itself, and cannot therefore be
the cause of the retardation which we are considering. There are
also electricians who will tell you that when magnetization is
suddenly evoked in an iron bar, there are induction currents set up
in the iron which oppose and delay its magnetization. That they
oppose the magnetization is perfectly true, but if you carefully
laminate the iron so as to eliminate eddy currents, you will find,
strangely enough, that the magnetism rises still more slowly to its
final value. For by laminating the iron you have virtually
increased the self-inductive action, and increased the time
constant of the circuit, so that the currents rise more slowly than
before. The lag is not in the iron, but in the magnetizing current,
and the current being retarded, the magnetization is of course
retarded also.

CONNECTING COILS FOR QUICKEST ACTION.

Now let us apply these most important though rather intricate
considerations to the practical problems of the quick working of
the electromagnet. Take the case of an electromagnet forming some
part of the receiving apparatus of a telegraph system in which it
is desired to secure very rapid working. Suppose the two coils that
are wound upon the horseshoe core are connected together in series.
The coefficient of self-induction for these two is four times as
great as that of either separately; coefficients of self-induction
being proportional to the square of the number of turns of wire
that surround a given core. Now if the two coils instead of being
put in series are put in parallel, the coefficient of
self-induction will be reduced to the same value as if there were
only one coil, because half the line current (which is practically
unaltered) will go through each coil. Hence the time constant of
the circuit when the coils are in parallel will be a quarter of
that which it is when the coils are in series; on the other hand,
for a given line current, the final magnetizing power of the two
coils in parallel is only half what it would be with the coil in
series. The two lower curves in Fig. 54 illustrate this, from which
it is at once plain that the magnetizing power for very brief
currents is greater when the two coils are put in parallel with one
another than when they are joined in series.

Now this circumstance has been known for some time to telegraph
engineers. It has been patented several times over. It has formed
the theme of scientific papers, which have been read both in France
and in England. The explanation generally given of the advantage of
uniting the coils in parallel is, I think, fallacious; namely that
the “extra currents” (i.e., currents due to self-induction) set up
in the two coils are induced in such directions as tend to help one
another when the coils are in series, and to neutralize one another
when they are in parallel. It is a fallacy, because in neither case
do they neutralize one another. Whichever way the current flows to
make the magnetism, it is opposed in the coils while the current is
rising, and helped in the coils while the current is falling, by
the so-called extra currents. If the current is rising in both
coils at the same moment, then, whether the coils are in series or
in parallel, the effect of self-induction is to retard the rise of
the current. The advantage of parallel grouping is simply that it
reduces the time constant.

BATTERY GROUPING FOR QUICKEST ACTION.

One may consider the question of grouping the battery cells from
the same point of view. How does the need for rapid working, and
the question of time constant, affect the best mode of grouping the
battery cells? The amateur’s rule, which tells you to so arrange
your battery that its internal resistance should be equal to the
external resistance, gives you a result wholly wrong for rapid
working. The supposed best arrangement will not give you (at the
expense even of economy) the best result that might be got out of
the given number of cells. Let us take an example and calculate it
out, and place the results graphically before our eyes in the form
of curves. Suppose the line and electromagnet have together a
resistance of 6 ohms, and that we have 24 small Daniell cells, each
of electromotive force say 1 volt, and of internal resistance 4
ohms. Also let the coefficient of self-induction of the
electromagnet and circuit be 6 quadrants. When all the cells are in
series, the resistance of the battery will be 96 ohms, the total
resistance of the circuit 102 ohms, and the full value of the
current 0.235 ampere. When all the cells are in parallel, the
resistance of the battery will be 0.133 ohm, the total resistance
6.133 ohms, and the full value of the current 0.162 ampere.
According to the amateur rule of grouping cells so that internal
resistance equals external, we must arrange the cells in 4
parallels, each having 6 cells in series, so that the internal
resistance of the battery will be 6 ohms, total resistance of
circuit 12 ohms, full value of current 0.5 ampere. Now the
corresponding time constants of the circuit in the three cases
(calculated by dividing the coefficient of self-induction by the
total resistance) will be respectively—in series, 0.06 sec.;
in parallel, 0.5 sec.; grouped for maximum steady current, 0.96
sec. From these data we may now draw the three curves, as in Fig.
55, wherein the abscissæ are the values of time in seconds
and the ordinates the current. The faint vertical dotted lines mark
the time constants in the three cases. It will be seen that when
rapid working is required the magnetizing current will rise, during
short intervals of time, more rapidly if all the cells are put in
series than it will do if the cells are grouped according to the
amateur rule.

FIG. 55.—CURVES OF RISE OF CURRENT WITH DIFFERENT GROUPINGS
OF BATTERY.

When they are all put in series, so that the battery has a much
greater resistance than the rest of the circuit, the current rises
much more rapidly, because of the smallness of the time constant,
although it never attains the same ultimate maximum as when grouped
in the other way. That is to say, if there is self-induction as
well as resistance in the circuit, the amateur rule does not tell
you the best way of arranging the battery. There is another mode of
regarding the matter which is helpful. Self-induction, while the
current is growing, acts as if there were a sort of spurious
addition to the resistance of the circuit; and while the current is
dying away it acts of course in the other way, as if there were a
subtraction from the resistance. Therefore you ought to arrange the
battery so that the internal resistance is equal to the real
resistance of the circuit, plus the spurious resistance during that
time. But how much is the spurious resistance during that time? It
is a resistance proportional to the time that has elapsed since the
current was turned on. So then it comes to a question of the length
of time for which you want to work it. What fraction of a second do
you require your signal to be given in? What is the rate of the
vibrator of your electric bell? Suppose you have settled that
point, and that the short time during which the current is required
to rise is called t; then the apparent resistance at time t after
the current is turned on is given by the formula:

R_t = R × e^(R/L)t + (
e^(R/L)t – 1 )

TIME CONSTANTS OF ELECTROMAGNETS.

I may here refer to some determinations made by M. Vaschy,⁴ respecting the coefficients of
self-induction of the electromagnets of a number of pieces of
telegraphic apparatus. Of these I must only quote one result, which
is very significant. It relates to the electromagnet of a Morse
receiver of the pattern habitually used on the French telegraph
lines.

It is interesting to note how the perfecting of the magnetic
circuit increases the self-induction.

Thanks to the kindness of Mr. Preece, I have been furnished with
some most valuable information about the coefficients of
self-induction, and the resistance of the standard pattern of
relays, and other instruments which are used in the British postal
telegraph service, from which data one is able to say exactly what
the time constants of those instruments will be on a given circuit,
and how long in their case the current will take to rise to any
given fraction of its final value. Here let me refer to a very
capital paper by Mr. Preece in an old number of the “Journal of the
Society of Telegraph Engineers,” a paper “On Shunts,” in which he
treats this question, not as perfectly as it could now be treated
with the fuller knowledge we have in 1890 about the coefficients of
self-induction, but in a very useful and practical way. He showed
most completely that the more perfect the magnetic circuit
is—though of course you are getting more magnetism from your
current—the more is that current retarded. Mr. Preece’e mode
of experiment was extremely simple. He observed the throw of the
galvanometer when the circuit which contained the battery and the
electromagnet was opened by a key which at the same moment
connected the electromagnet wires to the galvanometer. The throw of
the galvanometer was assumed to represent the extra current which
flowed out. Fig. 56 represents a few of the results of Mr. Preece’s
paper.

FIG. 56.—ELECTROMAGNETS OF RELAY, AND THEIR EFFECTS.

Take from an ordinary relay a coil, with its iron core, half the
electromagnet, so to speak, without any yoke or armature. Connect
it up as described, and observe the throw given to the
galvanometer. The amount of throw obtained from the single coil was
taken as unity, and all others were compared with it. If you join
up two such coils as they are usually joined, in series, but
without any iron yoke across the cores, the throw was 17. Putting
the iron yoke across the cores, to constitute a horseshoe form, 496
was the throw; that is to say, the tendency of this electromagnet
to retard the current was 496 times as great as that of the simple
coil. But when an armature was put over the top, the effect ran up
to 2,238. By the mere device of putting the coils in parallel,
instead of in series, the 2,238 came down to 502, a little less
than the quarter value which would have been expected. Lastly, when
the armature and yoke were both of them split in the middle, as is
done in fact in all the standard patterns of the British postal
telegraph relays, the throw of the galvanometer was brought down
from 502 to 26. Relays so constructed will work excessively
rapidly. Mr. Preece states that with the old pattern of relay
having so much self-induction as to give a galvanometer throw of
1,688, the speed of signaling was only from 50 to 60 words per
minute, whereas, with the standard relays constructed on the new
plan, the speed of signaling is from 400 to 450 words per minute.
It is a very interesting and beautiful result to arrive at from the
experimental study of these magnetic circuits.

SHORT CORES versus LONG CORES.

In considering the forms that are best for rapid action, it
ought to be mentioned that the effects of hysteresis in retarding
changes in the magnetization of iron cores are much more noticeable
in the case of nearly closed magnetic circuits than in short
pieces. Electromagnets with iron armatures in contact across their
poles will retain, after the current has been cut off, a very large
part of their magnetism, even if the cores be of the softest of
iron. But so soon as the armature is wrenched off, the magnetism
disappears. An air gap in a magnetic circuit always tends to hasten
demagnetizing. A magnetic circuit composed of a long air path and a
short iron path demagnetizes itself much more rapidly than one
composed of a short air path and a long iron path. In long pieces
of iron the mutual action of the various parts tends to keep in
them any magnetization that they may possess; hence they are less
readily demagnetized. In short pieces, where these mutual actions
are feeble or almost absent, the magnetization is less stable, and
disappears almost instantly on the cessation of the magnetizing
force. Short bits and small spheres of iron have no magnetic
memory. Hence the cause of the commonly received opinion among
telegraph engineers that for rapid work electromagnets must have
short cores. As we have seen, the only reason for employing long
cores is to afford the requisite length for winding the wire which
is necessary for carrying the needful circulation of current to
force the magnetism across the air gaps. If, for the sake of
rapidity of action, length has to be sacrificed, then the coils
must be heaped up more thickly on the short cores. The
electromagnets in American patterns of telegraphic apparatus
usually have shorter cores, and a relatively greater thickness of
winding upon them, than those of European patterns.

ELECTRIC ERYGMASCOPE.

The erygmascope is the name of an electric lighting apparatus
designed for the examination of the strata of earth traversed by
boring apparatus.

It consists of a very powerful incandescent lamp inclosed in a
metallic cylinder. One of the two semi-cylindrical sides
constitutes the reflector, and the other, which is of thick glass,
allows of the passage of the luminous rays, which thus illuminate
with great brilliancy the strata of earth traversed by the
instrument. The base, which is inclined at an angle of 45°, is
an elliptical mirror, and the top, of straight section, is open in
order to permit the observer standing at the mouth of the well, and
provided with a powerful spyglass, to see in the mirror the image
of the earth. The lamp is so mounted that its upwardly emitted rays
are intercepted.

The whole apparatus is suspended from a long cable, formed of
two conducting wires, which winds around a windlass with metallic
journals which are electrically insulated. These journals
communicate, through the intermedium of two friction springs, with
the conductors on the one hand and, on the other, with the poles of
an automatic and portable battery.

THE TROUVE ERYGMASCOPE.

This permits of lowering and raising the apparatus at will,
without derangement, and without its being necessary to interrupt
the light and the observation.—Revue Industrielle.

A NEW ELECTRIC BALLISTIC
TARGET.

The electrical target usually employed in determining velocities
of projectiles consists of a wooden frame on which is strung a
copper wire so as to make a continuous circuit arranged in parallel
vertical lines about one inch or one and one half inches apart.

It frequently happens that a projectile will pass through this
target without breaking the circuit, either by squeezing between
the wires or because, when last repaired, the target was
short-circuited unnoticed, so that the cutting of the wires did not
break the circuit. The repair of this target takes considerable
time.

Besides these objections to this target, another and more
serious one is the irregularity in the manner of breaking the
circuit. It has been proved that times required for a flat headed
and an ogival headed projectile to rupture the current are very
different.

To remedy these defects a new and very ingenious target has been
devised and used with great success at the United States Military
Academy at West Point. The top of the target is a wooden strip, F,
on the upper side of which are screwed strips of copper, A A, about
1/2 in. wide, and 1/8 in. thick. The connection between two
adjoining strips is made by a copper cartridge, C, which is dropped
in a hole in the frame bored to receive it. This cartridge is the
one used in the Springfield rifle. Inside the cartridge is a spiral
spring, S, which, acting on the bottom of the hole and the head of
the cartridge, tends to make the latter spring up, and so break the
circuit.

To the hook, H, which is attached to the cartridge, is
suspended, by means of a string, the lead weight, W, thus drawing
down the cartridge and making the circuit between A and A’. All the
weights being suspended the current comes in through the post, P,
passes along the copper strips and out of the corresponding post on
the other end.

On firing the projectile cuts a string, and the spring at once
causes the cartridge to spring up, thus breaking the circuit.

It is not possible for the projectile to squeeze between the
strings and not break the current, for in so doing the cartridge is
tipped slightly, which is sufficient, as it breaks the current on
one side.

This target is used in connection with the Boulenge chronograph.
Two targets are established at a known distance apart, say 50 ft.,
and the time required for the projectile to pass over this distance
is determined by finding the difference in the time of cutting of
the two targets, by finding the difference in the time of falling
of the two rods, caused by the demagnetization of two
electromagnets in the same circuit with the targets.

By means of a disjunctor both rods are dropped at the same time,
the shorter one releasing a knife blade which makes a cut on the
longer one. Now both rods are hung from the magnets again and the
gun is fired.

The projectile passes through the first target, breaks the
circuit, demagnetizes the magnet of the longer rod, and it begins
to fall. On passing through the second target, the projectile
causes the shorter rod to fall. This releases the knife blade, and
a second cut is made. The time corresponding to the distance
between these cuts is the time the longer rod was falling before
the second rod began to fall or the time between the cutting of the
two targets by the projectile.

The distance between the cuts is measured, and the time
corresponding to it can easily be found. Then the velocity of the
projectile is equal to 50/t.

To repair this target, strings are prepared in advance of
suitable length and looped at both ends, so that by placing the
hook of the cartridge in one loop and that of the weight in the
other the repair is quickly made.

This target has been used on the West Point proving ground to
determine velocities over distances of 100 ft. interval to
distances of only 9 ft. interval, and has given most satisfactory
results.

[Continued from SUPPLEMENT, No. 786, page
12566.]

THE OUTLOOK FOR APPLIED
ENTOMOLOGY.¹

LEGISLATION.

The amount of legislation in different countries that has of
late years been deemed necessary or sufficiently important, in view
of injurious insects, is a striking evidence of the increased
attention paid to applied entomology; and while modern legislation
of this kind has been, on the whole, far more intelligent than
similar efforts in years gone by, many of the laws passed have
nevertheless been unwise, futile, and impracticable, and even
unnecessarily oppressive to other interests. The chief danger here
is the intervention of politics or political methods. Expert
counsel should guide our legislators and the steps taken should be
thorough in order to be effective. We have had of late years in
Germany very good evidence of the excellent results flowing from
thorough methods, and the recent legislation in Massachusetts
against the gypsy moth (Ocneria dispar), which at one time
threatened to become farcical, has, fortunately, proved more than
usually successful; the commission appointed to deal with the
subject having worked with energy and followed competent
advice.

PUBLICATION.

On the question of publication of the results of our labors it
is perhaps premature to dwell at length. Each of the experiment
stations is publishing its own bulletins and reports quite
independently of the others, but after a uniform plan recommended
by the association with which we meet here; and with but one
exception that has come to my notice, another important
recommendation of the same association—that these
publications shall be void of all personal matter—has been
kept in mind. The National Bureau of Experiment Stations at
Washington is doing what it can with the means at command to
further the general work by issuing the Experiment Station Record,
devoted chiefly to digests of the State station bulletins. There is
a serious question in my mind as to the utility of State digests by
the national department of results already published extensively by
the different States and distributed under government frank to all
similar institutions and to whomsoever is interested enough to ask
for them.

Such digests may or may not be intelligently made, and, even
under the most favorable circumstances, will hardly serve any other
purpose than helping to the reference to the original articles, and
this could undoubtedly be done more satisfactorily to the stations
and to the people at large by general and classified indices to all
the State documents, made as full as possible and issued at stated
intervals. Only a small proportion of the bulletins have been so
far noticed by digest in this record, with no particular rule, so
far as I can see, in the selection. In point of fact, those will be
most apt to be noticed whose authors can find time to themselves
send or make for the purpose their own abstracts. This is, perhaps,
inevitable under present arrangements. Complete and satisfactory
digests of all, if intelligent and critical, imply a far greater
force than is at present at Prof. Atwater’s command.

Under these circumstances, it would seem wiser to devote all the
energies of the bureau to digests of the similar literature of
other countries, which would be of immense advantage to our people
and to the different station workers. Judging from the
recommendations and resolutions of the general association, this is
the view very generally held, but except in chemistry and special
industries like that of beet sugar, very little of that kind of
work has yet been attempted.

What is true of the station publications in general is equally
true of special publications. As entomologist of the department, I
have been urged to bring together, at stated intervals, digests of
the entomological publications of the different stations. Such
digests to be of any value, however, should also be critical, and
it were a thankless task for any one to be critic or censor even of
that which needs correction or criticism. Moreover, to do this work
intelligently would require increase of the divisional force, which
at present is more advantageously employed, for, as already
intimated, I should have great doubts of the utility of these
digests.

I believe, however, that the division should strive for such
increase of means as would justify the periodic publication, either
independently or as a part of the department record, of general and
classified indices to the entomological matter of the station
bulletins, and should work more and more toward giving results from
other parts of the world. This could, perhaps, best be done by
titles of subject and of author so spaced and printed on stout
paper that they could be cut and used in the ordinary card
catalogue. The recipient could cut and systematically place the
titles as fast as received.

As to the character of the matter of the entomological
bulletins, it will inevitably be influenced by the needs and
demands of the people of the respective States, and while
originality should be kept in mind, there must needs be in the
earlier years of the work much restatement of what is already well
known. That some results have been published of work which reflects
no particular credit upon our calling is a mere incident of the new
positions created. Yet we may expect marked improvement from year
to year in this direction, and without being invidious, I would
cite those of Prof. Gillette’s on his spraying experiments and on
the plum curculio and plum gouger, as models of what such bulletins
should be.

Although the resolution offered at our last meeting by Prof.
Cook, to the effect that purely descriptive matter should be
excluded from the station bulletins, met with no favor, but was
laid on the table, by the general association, I am in full
sympathy with this position and am strongly of the opinion that in
the ordinary bulletins such purely technical and descriptive matter
should be reduced to the necessary minimum consistent with
clearness of statement and accuracy, and that if it is desired, on
the part of the station entomologists, to issue technical and
descriptive papers, a separate series of bulletins were better
instituted for this class of matter.

Finally, for results which it is desired to promptly get before
the people, the agricultural press is at our disposal, and so far
as the entomological work of the department of agriculture is
concerned, the periodical bulletin, Insect Life, was
established for this purpose. Its columns are open to all station
workers, and I would here appeal to the members of the association
to help make it, as far as possible, national, by sending brief
notes and digests of their work as it progresses. Hitherto we have
been unable to make as much effort in this direction as we desired,
but in future it is our hope to make the bulletin, as far as
possible, a national medium through which the results of work done
in all parts of the country may quickly be put on record and
distributed, not only to all parts of our own country, but to all
parts of the world.

The rapid growth and development of the national department and
the multiplication of its divisions have necessitated special modes
of publication and rendered the annual report almost an anachronism
so far as it pretends to be what it at one time was—a pretty
complete report of the scientific and other work of the department.
The attempts which I have made through the proper authorities to
get Congress to order more pretentious monographic works in quarto
volume similar to those issued by other departments of the
government have not met with encouragement, and in this direction
many of the stations will, let us hope, be able to do better.

CO-OPERATION.

Every other subject that might be considered on this occasion
must be subordinate to the one great question of co-operation. With
the large increase of actual workers in our favorite field,
distributed all over the country, the necessity for some
co-operation and co-ordination must be apparent to every one. Just
how this should be brought about or in what direction we may work
toward it, will be for this association in its deliberations to
decide. Nor will I venture to anticipate the deliberations and
conclusions of the special committee appointed to take the matter
into consideration, beyond the statement that there are many
directions in which we can adopt plans for mutual benefit. Take,
for instance, the introduction and dissemination of parasites. How
much greater will be the chance of success in any particular case
if we have all the different station entomologists interested in
some specific plan to be carried out in co-operation with the
national department, which ought to have better facilities of
introducing specimens to foreign countries or to different sections
of our own country than any of the State stations.

Let us suppose that the fruit growers of one section of the
country, comprising several States in area, need the benefit in
their warfare against any particularly injurious insect of such
natural enemy or enemies as are known to help the fruit growers of
some other section. There will certainly be much greater chances of
success in the carrying out of any scheme of introduction if all
the workers in the one section may be called upon through some
central or national body to help in the introduction and
disposition of the desired material into the other section. Or,
take the case of the boll worm investigation already alluded to.
The chances of success would be much greater if the entomologists
in all the States interested were to give some attention to such
lepidopterous larvæ as are found to be affected with
contagious diseases and to follow out some specific plan of
cultivating and transmitting them to the party or parties with whom
the actual trials are intrusted. The argument applies with still
greater force to any international efforts. I need hardly multiply
instances. There is, it is true, nothing to prevent any individual
station entomologist from requesting co-operation of the other
stations, nor is there anything to prevent the national department
from doing likewise; but in all organization results are more apt
to flow from the power to direct rather than from mere liberty to
request or to plead. The station entomologist may be engrossed in
some line of research which he deems of more importance to the
people of his State, and may resent being called upon to divert his
energies; and with no central or national power to decide upon
plans of co-operation for the common weal, we are left to voluntary
methods, mutually devised, and it is here that this association
can, it seems to me, most fully justify its organization. And this
brings me to the question of

THE DEPARTMENT AND THE STATIONS.

Immediately connected with the question of co-operation is the
relation of the National Department of Agriculture and the State
experiment stations. The relation, instead of being vital and
authoritative, is, in reality, a subordinate one. Many persons
interested in the advancement of agriculture foresaw the advantage
of having experiment stations attached to the State agricultural
colleges founded under the Morrill act of 1862; but I think that in
the minds of most persons the establishment of these stations
implied some such connection with the national department as that
outlined in an address on Agricultural Advancement in the United
States, which I had the honor to deliver in 1879 before the
National Agricultural Congress, at Rochester, and in which the
following language was used:

“In the light of the past history of the German experimental
stations and their work, or of that in our own State of
Connecticut, the expediency of purchasing an experimental farm of
large dimensions in the vicinity of Washington is very
questionable. There can be no doubt, however, of the value of a
good experimental station there that shall have its branches in
every State of the Union. The results to flow from such stations
will not depend upon the number of acres at command, and it will be
far wiser and more economical for the commissioner to make each
agricultural college that accepted the government endowment
auxiliary to the national bureau, so that the experimental farm
that is now, or should be, connected with each of these
institutions might be at its service and under the general
management of the superintendent of the main station. There is
reason to believe that the directors of these colleges would
cheerfully have them constituted as experimental stations under the
direction of the department, and thus help to make it really
national—the head of a vast system that should ramify through
all parts of the land….

“With the different State agricultural colleges, and the State
agricultural societies, or boards, we have every advantage for
building up a national bureau of agriculture worthy of the country
and its vast productive interests, and on a thoroughly economical
basis, such as that of Prussia, for instance.”

In short, the view in mind was something in the nature of that
which has since been adopted by our neighbors of the North, where
there is a central or national station or farm at Ottawa and
sub-stations or branch farms at Nappan, Nova Scotia, Brandon,
Manitoba, Indian Head, N.W.T., and Agassiz, British Columbia, all
under the able direction of Mr. William Saunders, one of our
esteemed fellow workers. It was my privilege to be a good deal with
Mr. Saunders when he was in Europe studying the experience of other
countries in this matter, and the policy finally adopted in Canada
as a result of his labors is an eminently wise one, preventing some
of the difficulties and dangers which beset our plan, whether as
between State and nation or college and station.

Under the present laws and with the vast influence which the
Association of Agricultural Colleges and Experiment Stations will
wield, both in Congress and in the different States, there is great
danger of transposition, in this agricultural body politic, of
those parts which in the animal body are denominated head and tail,
and the old saw to the effect that “the dog wags the tail because
the tail cannot wag the dog,” will find another application. So far
as the law goes, the national department, which should hold a truly
national position toward State agricultural institutions depending
on federal support, can do little except by suggestion, whether in
the line of directing plans or in any way co-ordinating or
controlling the work of the different stations throughout the
country. The men who influenced and shaped the legislation which
resulted in the Hatch bill were careful that the department’s
function should be to indicate, not to dictate; to advise and
assist, not to govern or regulate. We have, therefore, to depend on
such relationships and such plans of co-operation as will appear
advantageous to all concerned, and these can best be brought about
through such associations as are now in convention here.

Without such plans there is great danger of such waste of energy
and means and duplication of results as will bring the work into
popular disfavor and invite disintegration, for already there is a
growing feeling that agricultural experiment is and will be
subordinated to the ordinary college work in the disposition of the
federal appropriations.

What is true of the national department as a whole in its
connection with the State stations is true in a greater or less
degree of the different divisions of the department in connection
with the different specialists of the stations. With the
multiplicity of workers in any given direction in the different
States, the necessity for national work lessens. A favorite scheme
of mine in the past, for instance (and one I am glad to say fully
indorsed by Prof. Willits), was to endeavor to have a permanent
agent located in every section of the country that was sufficiently
distinctive in its agricultural resources and climate, or, as a yet
further elaboration of the same plan, one in each of the more
important agricultural States. The necessity for such State agents
has been lessened, if not obviated, by the Hatch bill, and the
subsequent modifications looking to permanent appropriations to the
State stations or colleges, which give no central power at
Washington. The question then arises, What function shall the
national department perform? Its influence and field for usefulness
have been lessened rather than augmented in the lines of actual
investigation in very many directions. Many a State is already far
better equipped both as to valuable surrounding land, laboratory
and library facilities, more liberal salaries, and greater freedom
from red tape, administrative routine, and restrictions as to
expenditures, than we are at Washington; and, except as a directing
agent and a useful servant, I cannot see where the future growth of
the department’s influence is to be outside of those federal
functions which are executive. Just what that directing influence
is to be is the question of the hour, not only in the broader but
in the special sense. The same question, in a narrower sense, had
arisen in the case of the few States which employed State
entomologists. In the event, for instance, of an outbreak of some
injurious insect, or in the event of any particular economic
entomological question within the limits of the State having such
an officer, the United States entomologist would naturally feel
that any effort on his part would be unnecessary, or might even be
looked upon as an interference. He would feel that there was always
danger of mere duplication of observation or experiment, except
where appealed to for aid or co-operation. This is, perhaps, true
only of insects which are local or sectional, and is rather a
narrow view of the matter, but it is one brought home from
experience, and is certainly to be considered in our future plans.
The favor with which the museum work of the national division was
viewed by you at the meeting last November and the amount of
material sent on for determination would indicate that the building
up of a grand national reference collection will be most useful to
the station workers. But to do this satisfactorily we need your
co-operation, and I appeal to all entomologists to aid in this
effort by sending duplicates of their types to Washington, and thus
more fully insuring against ultimate loss thereof.

STATUS OF OUR SOCIETY.

This train of thought brings up the question of the status of
our society with the station entomologists as represented by the
committee of the general association. Those of us who had desired a
national association for the various purposes for which such
associations are formed, felt, I believe, if I may speak for them,
that the creation of the different experimental stations rendered
such an organization feasible. Your organization at Toronto and the
constitution adopted and amended at the meeting at Washington all
indicate that the chief object was the advancement of our chosen
work and that the strength of the association would come from the
experiment station entomologists. There was then no other
organization of the kind, nor any intimation that such a one would
be founded. Some of us therefore were surprised to learn from the
circular sent out by Prof. Forbes, its chairman, that the committee
appointed by the association of agricultural colleges and
experiment stations, and through which we had hoped to communicate
and co-operate with that association, was not in the proper sense a
committee, but a section which has prepared (and in fact was
required by the executive committee and the rules of the superior
body to prepare) a programme of papers and discussions for the
meeting to be held at the same time and place with our own. I
cannot but feel that this is in some respects a misfortune, and it
will devolve upon you to decide upon several questions of
importance that will materially affect our future existence. That
there is not room for two national organizations having the same
objects in view and meeting at the same time and place goes, I
think, without saying; and if the committee of the general
association is to be anything more than a committee in the proper
sense of the word, or if it is to assume with or without formal
constitution the functions of our own association, then our own
must necessarily be crippled, and to do any good at all must meet
at a different time and a different place. A committee or section,
or whatever it may be called, of the general association with which
we meet, would preclude active membership of any but those who come
within the constitution of that body. Our Canadian friends and many
others who have identified themselves with applied entomology, and
do not belong to any of our State or government institutions, would
be debarred from active representation, however liberal the
association may have been in inviting such to participate, without
power to vote in its deliberations. Our own association has, or
should have, no such limitations. Some of us who are entitled to
membership in both bodies may feel indifferent as to the course
finally decided upon, and that it will not make any difference
whether we have an outside and independent organization, as that of
the association of official chemists, or whether we do, as did the
botanists and horticulturists, waive independence in favor of more
direct connection with the general association, provided there is
some way whereby the committees of the general association are
given sufficient latitude and time to properly present their papers
and deliberate; but there are others who feel more sensitive as to
their action and are more immediately influenced by the feelings of
the main body. I hope that whatever action be taken at this
meeting, the general good and the promotion of economic entomology
will be kept in mind and that no sectional or personal feeling will
be allowed to influence our deliberations.

SUGGESTION AND COMMENT.

You will, I know, pardon me if, before concluding these remarks,
I venture to make a few comments which, though not altogether
agreeable, are made in all sincerity and in the hope of doing good.
The question as to how far purely technical and especially
descriptive and monographic work should be done by the different
stations or by the national department is one which I have already
alluded to and upon which we shall probably hold differing
opinions, and which will be settled according to the views of the
authorities at the different stations. Individually, I have ever
felt that one ostensibly engaged in applied entomology and paid by
the State or national government to the end that he may benefit the
agricultural community can be true to his trust only by largely
overcoming the pleasure of entomological work having no practical
bearing. I would, therefore, draw the line at descriptive work
except where it is incidental to the economic work and for the
purpose of giving accuracy to the popular and economic statements.
This would make our work essentially biological, for all biologic
investigation would be justified, not only because the life habits
of any insect, once ascertained, throw light on those of species
which are closely related to it, but because we can never know when
a species at present harmless may subsequently prove harmful, and
have to be classed among the species injurious to agriculture.

On the question of credit to their original sources of results
already on record, it is hardly necessary for me to advise, because
good sense and the consensus of opinion will in the end justify or
condemn a writer according as he prove just and conscientious in
this regard.

There is one principle that should guide every careful writer,
viz., that in any publications whatever, where facts or opinions
are put forth, it should always be made clear as to which are based
upon the author’s personal experience and which are compiled or
stated upon the authority of others. We should have no patience
with a very common tendency to set forth facts, even those relating
to the most common and best known species, without the indications
to which I have referred. The tendency belittles our calling and is
generally misleading and confusing, especially for bibliographic
work, and cannot be too strongly deprecated.

On this point there will hardly be any difference of opinion,
but I will allude to another question of credit upon which there
prevails a good deal of loose opinion and custom. It is the habit
of using illustrations of other authors without any indication of
their original source.

This is an equally vicious custom and one to be condemned,
though I know that some have fallen into the habit, without
appreciation of its evil effect. It is, in my judgment, almost as
blameworthy as to use the language or the facts of another without
citing the authority.

Every member of this association who has due appreciation of the
time and labor and special knowledge required to produce a good and
true illustration of the transformations and chief characteristics
of an insect will appreciate this criticism. However pardonable in
fugitive newspaper articles in respect of cuts which, from repeated
use, have become common or which have no individuality, the habit
inevitably gives a certain spurious character to more serious and
official publications, for assumption of originality, whether
intended or not, goes with uncredited matter whether of text or
figure. Nor is mere acknowledgment of loan or purchase to the
publisher, institution or individual who may own the block or stone
what I refer to. But that acknowledgment to the author of the
figure or the work in which it first appears which is part of
conscientious writing, and often a valuable index as to the
reliability of the figure.

It were supererogation to point out to a body of this kind the
value of the most careful and thorough work in connection with life
histories and habits, often involving as it does much microscopic
study of structure. The officers of our institutions who control
the funds, and more or less fully our conduct, are apt to be
somewhat impatient and inappreciative of the time given to anatomic
work, and where it is given for the purpose of describing species
and of synopsizing or monographing higher groups, without reference
to agriculture, I am firmly of the belief that it diverts one from
economic work, but where pursued for a definite economic purpose it
cannot be too careful or too thorough and I know of no instances
better calculated to appeal to and modify the views of those
inclined to belittle such structural study than Phylloxera and
Icerya. On the careful comparison of the European and American
specimens of Phylloxera vastatrix, involving the most minute
structures and details, depended originally those important
economic questions which have resulted in legislation by many
different nations and the regeneration of the affected vineyards of
Europe, of our own Pacific coast, and of other parts of the world
by the use of American resistant stocks. In the case of Icerya
purchasi the possibilities of success in checking it by its
natural enemies hung at one time upon a question of specific
difference between it and the Icerya sacchari of
Signoret—a question of minute structure which the
descriptions left unsettled and which could only be settled by the
most careful structural study and the comparison of the types,
involving a trip to Europe.

CONCLUSION.

I have thus touched, gentlemen, upon a few of the many subjects
that crowd upon the mind for consideration on an occasion like
this—a few gleanings from a field which is passing rich in
promise and possibility. It is a field that some of us have
cultivated for many years and yet have only scratched the surface,
and if I have ventured to suggest or admonish, it is with the
feeling that my own labors in this field are ere long about to end
and that I may not have another occasion.

At no time in the history of the world has there, I trow, been
gathered together such a body of devoted and capable workers in
applied entomology. It marks an era in our calling and, looking
back at the progress of the past fifteen years, we may well ponder
the possibilities of the next fifteen. They will be fruitful of
grand results in proportion as we persistently and combinedly
pursue the yet unsolved problems and are not tempted to the
immediate presentation of separate facts, which are so innumerable
and so easily observed that their very wealth becomes an element of
weakness. Epoch-making discoveries result only from this power of
following up unswervingly any given problem, or any fixed ideal.
The kerosene emulsion, the Cyclone nozzle, the history of
Phylloxera vastatrix, of Phorodon humuli, of
Vedalia cardinalis, are illustrations in point, and while we
may not expect frequent results as striking or of as wide
application as these, there is no end of important problems yet to
be solved and from the solution of which we may look for similar
beneficial results. Applied entomology is often considered a sordid
pursuit, but it only becomes so when the object is sordid. When
pursued with unselfish enthusiasm born of the love of investigation
and the delight in benefiting our fellow men, it is inspiring, and
there are few pursuits more deservedly so, considering the vast
losses to our farmers from insect injury and the pressing need that
the distressed husbandman has for every aid that can be given him.
Our work is elevating in its sympathies for the struggles and
suffering of others. Our standard should be high—the pursuit
of knowledge for the advancement of agriculture. No official
entomologist should lower it by sordid aims.

During the recent political campaign the farmer must have been
sorely puzzled to know whether his interests needed protection or
not. On the abstract question of tariff protection to his products
we, as entomologists, may no more agree than do the politicians or
than does the farmer himself. But ours is a case of protection from
injurious insects, and upon that there can nowhere be division of
opinion. It is our duty to see that he gets it with as little tax
for the means as possible.

POTASH SALTS.¹

My attention was attracted to potash salts as an insecticide, by
the casual remark of an intelligent farmer, that washing his young
pear trees with a muriate of potash solution cleared them of
scales. The value of this substance for insecticide purposes,
should its powers be sufficient, struck me at once, and I began
investigation. It was unluckily too late in the season for field
experiments of the nature desired; but it is the uniform testimony
of farmers who have used either the muriate or the kainit in the
cornfields, that they have there no trouble with grubs or cut
worms. Mr. E.B. Voorhees, the senior chemist of the station,
assures me that on his father’s farm the fields were badly
infested, and replanting cornhills killed by grubs or wire worms
was a recognized part of the programme. Since using the potash
salts, however, they have had absolutely no trouble, and even their
previously worst-infested fields show no further trace of injury.
The same testimony comes from others, and I feel safe in
recommending these salts, preferably kainit, to those who are
troubled with cut worms or wire worms in corn.

EXPERIMENTS.

A lot of wire worms (Iulus sp.) brought in from potato
hills were put into a tin can with about three inches of soil and
some potato cuttings, and the soil was thoroughly moistened with
kainit, one ounce to one pint of water. Next morning all the
specimens were dead. A check lot in another can, moistened with
water only, were healthy and lived for some days afterward.

A number of cabbage maggots placed on the soil impregnated with
the solution died within twelve hours.

To test its actual killing power, used the solution, one ounce
kainit to one pint water, to spray a rose bush badly infested with
plant lice. Effect, all the lice dead ten hours later; the younger
forms were dropping within an hour.

Sprayed several heads of wheat with the solution, and within
three hours all the aphides infesting them were dead.

Some experiments on hairy caterpillars resulted
unsatisfactorily, the hair serving as a perfect protection against
the spray, even from the atomizer.

To test its effect on the foliage, sprayed some tender shoots of
rose and grape leaves, blossoms, and clusters of young fruit. No
bad effect observable 24 hours later. There was on some of the
leaves a fine glaze of salt crystals, and a decided salt taste was
manifest on all.

Muriate of potash of the same strength was tested as follows:
Sprayed on some greenhouse camellias badly infested by mealy bugs,
it killed nearly all within three hours, and six hours later not a
living insect was found. The plants were entirely uninjured by the
application.

Thoroughly sprayed some rose bushes badly infested with aphides,
and carried off some of the worst branches. On these the lice were
dead next morning; but on the bushes the effect was not so
satisfactory, most of the winged forms and many mature wingless
specimens were unaffected, while the terminal shoots and very young
leaves were drooping as though frosted. All, however, recovered
later.

The same experiment repeated on other, hardier roses, resulted
similarly so far as the effect on the aphides was concerned, but
there was no injury to the plant.

Used this same mixture on the caterpillars of Orgyia
leucostigma with unsatisfactory effect, and with the same
results used it on a number of other larvæ. Used on the rose
leaf roller, Cacæcia rosaceana, it was promptly
effective.

Tested for injury to plants, it injured the foliage and flowers
of wisteria, the younger leaves of maple and grape, and the finer
kinds of roses.

From these few experiments kainit seems preferable to the
muriate, as acting more effectively on insects and not injuriously
on plants. For general use on plants it is not to be recommended.
It is otherwise on underground species, where the soil will be
penetrated by the salts and where the moisture evaporates but
slowly, and the salt has a longer and better chance to act. The
best method of application would be a broadcasting in fertilizing
quantity before or during a rain, so as to carry the material into
the soil at once. In cornfields infested with grubs or wire worms,
the application should be made before planting. Where it is to be
used to reach root lice, it should be used when the injury is
beginning. When strawberry beds are infested by the white grub, the
application should be made when cultivating or before setting
out.

The potash salts have a high value as fertilizers, and any
application made will act as a stimulant as well as insecticide,
thus enabling the plants to overcome the insect injury as well as
destroying the insect.

In speaking on this subject in Salem county, I learned from
farmers present that those using potash were not troubled with the
corn root louse to any extent, and also that young peach trees have
been successfully grown in old lice-infested orchards, where
previously all died, by first treating the soil with kainit of
potash.

A meteorological station has been
built on Mont Blanc, at an elevation of 13,300 feet, under the
direction of M. Vallot. It required six weeks to deliver the
materials. The instruments are self-registering and are to be
visited in summer every fifteen days if possible, the instruments
being left to register between the visits. In the winter the
observatory will be entirely inaccessible. This is the highest
scientific station in Europe, but is 847 feet lower than the Pike’s
Peak station in Colorado.

THE EXPENSE MARGIN IN LIFE
INSURANCE.

The principle of mutuality requires that the burden of expense
in life insurance should be borne by all the members equally; but,
even with the most careful adjustment, the allowance usually made
is considerably in excess of what is needed in the regular
companies doing business on the “level premium” plan.

It is customary in these companies to add to the net premium a
percentage thereof to cover the expense account. This practice,
though in harmony with the “commission system,” is so clearly
defective and so far removed from the spirit of life insurance
mathematics, that it scarcely deserves even this passing
notice.

It is generally understood that these corporations combine the
functions of the savings bank and life insurance company, and it is
only by separating the two in our minds as far as possible that we
can obtain a clear conception of the laws that should govern the
apportionment of the expenses among the great variety of
policies.

While it is a comparatively simple matter to state the amount of
either the insurance or savings bank element in a single policy, it
is by no means easy, as things go, to classify the company’s actual
expenses on this basis.

Fortunately, we can pretty accurately determine what these
amounts should be in any particular case.

In the first place, there are institutions in our midst devoted
solely to receiving and conserving small sums of money; doing, in
fact, exactly what our insurance companies are undertaking to do
with the reserve and contributions thereto. These savings banks are
required by law to make returns to the State commissioner, from
whose official report we can get a very good idea of the expense
attendant on doing this business.

Confining ourselves to the city banks, where the conditions more
nearly resemble those of the insurance companies, we find in
thirty-eight combined institutions for saving in the State of
Massachusetts a deposit in 1888 of $192,174,566, taken care of at
an aggregate cost of $455,387, or about 24-100 of one per cent.

The same ratio carried out for all the savings banks in
Massachusetts gives a trifle over 25-100 of one per cent.; we may,
therefore, consider ¼ of one per cent. as expressing pretty
nearly the cost of receiving, paying out, and investing the savings
of the people.

We must remember in this connection that in the popular
estimation, the savings bank is an important factor in the public
welfare, and in the towns and smaller cities there are often found
public spirited men willing to give their services to encourage
this mode of saving; but public sentiment has not yet given to life
insurance the place which it is destined, sooner or later, to
occupy by the side of the savings bank. Hence the services of able
managers can only be obtained by a liberal outlay of the corporate
funds. A satisfactory adjustment of the matter of expenses will,
perhaps, do more than anything else to bring about this recognition
on the part of the public.

In the case of the savings bank it is safe to say that for
double the present outlay a liberal salary could be paid to all the
officers. Following the analogy, we are led to infer that if this
be the case in savings banks, then ½ of one per cent. of the
reserve should be an ample allowance for the special labor required
in the purely banking portion of the business.

In this we have the concurrence of the late Elizur Wright. In an
essay on this subject he says:

“The expenses of the five largest savings banks in Boston, in
1869, did not exceed 4-10 of one per cent. on $28,000,000 deposited
in them. They certainly had twice as many transactions, in
proportion to the deposits, as any life insurance company could
have with the same amount of reserve, so that ½ of one per
cent. on the reserve seems to be ample for all working expenses
save those of maintaining the agencies and collecting the
premiums.”

This need hardly be looked upon as an admission that it costs
twice as much to care for the funds of a life insurance company as
for those of a savings bank. A liberal expense allowance must be
made at the outset, seeing that an error in this particular cannot
easily be rectified after the policy is issued. The dividend, or,
to speak more correctly, the annual return of surplus, will correct
any overpayment on this account.

There is another expense which seems inevitable. This is the
government tax on insurance companies, amounting in the aggregate
to nearly 1/3 of one per cent. on the reserve.

When we consider that these institutions are intended to
encourage thrift and to relieve the community from the care of
numberless widows and orphans, it seems a clear violation of the
principles of political economy to levy a tax on this business;
still, whatever our opinion may be as to the justice or injustice
of the imposition, the tax is maintained and must be provided for.
Consequently a further allowance of ½ of one per cent. must
be added to the net premium to cover the same, making a total of 1
per cent. of the reserve for banking expenses and taxes.
Considering this point as settled for the time being, let us
proceed to investigate the insurance expenses.

Here, again, we are fortunate in being able to refer to the
official reports of a class of corporations doing nearly, if not
quite pure insurance.

The assessment societies, outside of the fraternal and
benevolent, reporting in 1889 to the insurance commissioner of
Massachusetts, show outstanding risks amounting to $733,515,366.
Losses to the amount of $7,270,238 were paid during the year at a
cost for transacting the business of $2,403,053, which includes
among other items “agency expenses and commissions,” which amount
to about $1,203,000, or 17 per cent. of the cost value of the
insurance actually done. It would seem as if an allowance of 20 per
cent. would be a liberal one in the case of the regular companies,
which surely have as good facilities for doing business as the
assessment societies.

As far as insurance is concerned, there is less difference
between regular and co-operative companies than is generally
supposed. Regular companies assess each policy in advance for a
year’s insurance at a time, while co-operative societies furnish
insurance only from one assessment to another. The difficulty in
the way of collecting the assessment in the latter case would seem
to be greater than in the former, owing to the more permanent
nature of the regular insurance contract.

In compensating agents the assessment companies naturally pay in
proportion to the insurance obtained, inasmuch as there is no other
basis to go upon, but regular companies usually pay the agent a
percentage of the premium which includes a considerable trust
fund over and above the assessment for actual insurance. It is
easily seen that by the last method the agent’s compensation
increases in proportion to the amount of savings bank business
forced upon the company.

To realize how far we are from anything like a scientific, not
to say common sense basis for insurance expenses, we have but to
examine the following list, which gives the ratios between the
expenditures for general expenses in 1889, and those for the
extension of the business. For every $100 used in a general way,
the different companies spend for commissions and agency expenses:
$37, $66, $67, $78, $91, $106, $110, $113, $120, $140, $157, $161,
$173, $175, $186, $189, $200, $202, $222, $264, $311, $346.

It will doubtless be said that I am taking a very advanced
position when I say that in the ideal life insurance scheme there
is no place for the commission system. Solicitors will be a
necessity only so long as they are in the field, but fifty years of
life insurance has taught our community its true value and, thanks
to the modern press, the institution it is no more likely to fall
into desuetude than is Christianity or the moral law.

For the convenience of bringing the company to the individual,
the latter should be willing to pay a fee. The man who renders
another a service or puts his superior knowledge at another’s
disposal should look to the party benefited for his remuneration.
Any compensation given for such service to a go-between by a mutual
company is paid by all, and the question arises, Is the advantage
to the company of sufficient importance to warrant the imposition
of this tax upon all its members promiscuously? The following, from
the Massachusetts Insurance Commissioner’s Report for 1885, leaves
no doubt as to the convictions of the writer on this important
matter:

“The expensiveness of the life insurance policy is not because
the level net premium is too high, for the premium is absolutely
just, and the policy holder gets full value; but the complaint
justly applies to the excessive expense charge. A person who wants
insurance, life or fire or other, should be able to buy it at first
cost without paying tribute of profits to middlemen. To that
complexion the matter will finally be brought by the force of
intelligent opinion, whatever resistance may be opposed by persons
whose thrift lies in the perpetuation of the expensive system now
in fashion.”

It requires but a slight degree of prophetic vision to predict
that in a very few years the companies in self defense will be
obliged to change their method of compensating agents.

Several companies have already begun the reform by grading
commissions; granting a percentage proportional to the amount of
insurance likely to be done on the policy. Other companies have
simply reduced the amount of the commission rate, thus virtually
withdrawing from active competition.

This will, in a certain degree, explain the wide variation in
the figures given above, where it is noticed that, in five
companies out of twenty-two, the total agency expenditures amount
to less than the general expenses, while in six cases the companies
spend more than double as much on the former as on the latter. In
either class we find representatives of the five largest companies
in the country.

On applying the foregoing ratios to the business of the existing
companies we find that, calling the theoretical expenses $100, the
actual expenditures for 1889 were as follows: $112.67, $118.34,
$150.40, $194.48, $208.16, $208.53, $228.66, $235.89, $248.44,
$250.79, $258.33, $258.57, $265.14, $267.19, $267.92, $274.47,
$294.17, $314.96, $335.70, $377.94, $616.70.

In this discouraging exhibit there is one ray of comfort. The
combined assets of the two companies heading the list amount to
over $100,000,000. There is no question as to their financial
standing, and both show a large increase in membership over the
previous year. I may also say here that it is a difficult matter to
get at the actual “cost of insurance” in the various companies.
Many of them, on their own acknowledgment, do not compute the
advance cost of carrying their “amount at risk,” and others, for
reasons of their own, do not care to state the figures. In cases
where the correct figures were not obtainable, I have assumed the
cost to have been 1-1/3 per cent. of the mean amount at risk.

If we should, in our comparison, omit the actual agency expenses
and commissions, the ratios would stand as follows:

Where I would allow $100 the companies actually used: $43.17,
$55.90, $65.21, $77.21, $82.39, $88.34, $91.99. $91.98. $92.19,
$94.65, $97.15. $99.55. $99.11. $102.86, $109.35, $125.05, $133.03,
$141.92, $195.90, $207.06, $287.72.

As might be supposed, the first two ratios are those companies
before alluded to. These companies might have doubled their
advertising account and expended $300,000 between them on agents’
salaries, and still have kept within my allowance.

Admitting, for the present at least, the reasonableness of the
proposed allowance for the expenses of the banking and insurance
departments of the business, we have before us the problem how to
equitably adjust the burden among the great variety of
policies.

In the first place, there should be no policy in the company
that does not contribute its proportionate share of the expense
allowance during every year of its life. I make a special point
of this, for at present the policies which have become paid up,
either by the payment of a single premium at the outset or by the
completion of a stipulated number of payments, contribute
practically nothing to the expense account after the premium
payments cease.

The following plan, I think, complies with all the requirements
of the problem. By the proposed method every policy, at all stages
of its existence, contributes its exact share to the expense fund,
whatever its plan of payment may be.

Let us, as an illustration, examine the case of a ten year
endowment policy, taken out at age 30, and consider it under three
aspects, first, as paid for in advance by a single payment, second,
as paid by five annual payments, and third, as paid for annually
throughout the term. I have used this short term endowment policy
simply for convenience, the rule applying equally to policies of
longer term or to the ordinary life policy, which is, in fact, an
endowment policy payable at death or age 100.¹

Taking the case of the single premium endowment policy for
$1,000, we find that the following sums are required, each year to
provide for the care of the reserve and to pay the government fees
(1 per cent. of reserve):

The insurance expenses should be covered by the 20 per cent.
allowance given below:

Consequently the total contribution required from this policy
each year is:

The present value of all these contributions is found to be, at
4 per cent. interest, $71.6394; in other words, this sum paid at
the outset, provides a fund from which we may deduct the current
expenses of each year in advance, and by accumulating the balance
at the assumed rate of interest from year to year, we shall have
enough to pay the anticipated expenses, leaving nothing over.

In the above case the sums in hand at the beginning of the year
are as follows:

We find a somewhat different condition existing during the first
years of a 5-year endowment policy. As there is more insurance and
less banking, the requirements are as follows:

As the premium payments extend over only five years, the expense
contributions must all be paid during that time and are most
conveniently made by a uniform addition to the net premium.

The present value of the amounts in column 3 is $60.0819, and
the equivalent annuity for five years is $12.9769. This amount,
received for five consecutive years, will put the company in funds
to pay current expenses and leave a reserve of $42.6981 at the
beginning of the sixth year, which, as we have seen in the analysis
of the single-premium policy, is the sum required for future
expenses on the paid up basis.

In like manner we find that the 10-year annuity equivalent to
the present value of the annual contributions in the case of an
annual-payment policy is $5.534, thus:

The present value of the ten yearly expense items given in the
“total” column above is $46.6812, which is equal to a ten-year
annuity of $5.534. The several premiums stand now as follows:

ENDOWMENT: $1,000, AGE 30, PAYABLE AT DEATH OR
40

By the actuaries’ rate we have, with the customary loading for
expense:

Single premium: $721.66 (loaded, $34.36). Five premiums, $188.70
(loaded $37.78). Annual premium, $105.65 (loaded $21.11).

Admitting the correctness of the new method, we must conclude
that the present single premium is not sufficiently loaded to cover
its own expenses, while the annual payment policy pays more than
its just share. A prominent and thoroughly informed life insurance
president says in this connection: “Many of the policies,
particularly the short term endowments, are charged with too high a
percentage of expenses to prove a good investment at maturity or
profitable to the insured in case of surrender.” This is not to be
wondered at when the applicant for a 10-year endowment policy sees
at a glance that he must pay, in the gross, more than is returned
unless he should die in the interim, in which case a plain “life”
or “term” policy would have answered the purpose. Under the new
system of assessing expenses one form is as desirable as another,
from the standpoint of the insured or the company.

The new premium for the 10-year endowment policy, $89.71,
commends itself at once to the applicant, who can easily see that
his total outlay must fall short of the amount ultimately to be
realized, of course, disregarding interest and probable dividends
in both cases.

In discounting the future expense contributions I have not taken
the chances of dying into account. Hence the expense reserve in any
instance applies only to that individual case, and, in the event of
death or surrender before the maturity of the policy, the amount of
the expense fund not used would naturally revert to the
insured.

The scheme of expense assessment outlined above will doubtless
be pronounced impracticable by the majority of insurance men.

Such a far reaching reform is too much to hope for, at least in
the immediate future.

No well informed life insurance expert will deny that there are
opportunities for improvement in the business, but to graft new
methods on old companies is a hopeless undertaking.

It is well, however, to have new methods well matured in advance
of the public demand, and I feel convinced that the ideas here set
forth are in the line of the reform which, before long, must be
instituted by the companies if they would retain the confidence and
patronage of the community.

Doubtless many insurance presidents could tell of suggestions
which have impressed them favorably and which they would gladly
have adopted were it not for the injustice done thereby to older
members and the changes necessary to bring existing contracts into
conformity with the new system. Similar objections may be urged
against the ideas here advanced, and I must confess I hardly see a
way by which the present suggestions can be utilized by existing
companies. We can only hope that sooner or later some of the new
theories may be practically tested. Meanwhile the companies at
present in the field are doing a great work for the good of
humanity, even though their methods may be, in some particulars,
more practical than scientific.

THE FLOOD AT KARLSBAD.

During the flood which occurred in Germany and Bohemia, the last
week of November, Karlsbad was especially unfortunate; it suffered
such an inundation as had never before been known in the
“Sprudelstadt.” On the evening of November 23, the Tepl was very
much swollen by the rain, which had continued for several days, but
it was supposed that there was no danger of a flood, as the bed of
the river had been put in proper condition. During the forenoon of
November 24, the water suddenly began to rise with such astonishing
rapidity that within half an hour all the lower streets were like
turbulent rivers and the Alte and Neue Wiese were transformed into
a lake. The stores on the Alte Wiese were under water to the roofs,
and the proprietors, who were trying to save their goods, were
surprised by the water and had to take refuge in the trees. They
were rescued by having ropes thrown to them, and during this work a
catastrophe occurred which was a great misfortune to all classes of
citizens. The beloved burgermeister of Karlsbad, Dr. Rudolf Knoll,
who had just recovered from a severe illness, was, with others,
directing the work from the balcony of one of the houses, when a
rope by which a man was being drawn through the water broke, and
the man was carried off by the waves. The fright and excitement of
the scene gave the burgermeister a shock which caused his instant
death, but the man who was in danger was brought safely out of the
water.

The water was 9 ft. in Marienbaderstrasse, the Marktplatz,
Muhlbadgasse, the Sprudelgasse, Kreuzgasse, Kaiserstrasse, and
Egerstrasse, and flooded the quay, causing great destruction. All
places of business were flooded, the doors and iron shutters were
pushed in by the force of the water and the goods were carried away
or ruined.

The house called “Zum Kaffeebaum” was undermined and part of it
fell to the ground; the same fate was feared for other buildings.
The Sophien and Curhaus bridges were carried away. Other bridges
were greatly damaged, and the masonry along the banks of the river
was partially destroyed. The Sprudelgasse was completely washed
out, and the condition of the Muhlbadgasse was almost as bad. The
fire department with its apparatus had great difficulty in saving
the inhabitants and guests, as there were very few boats or
pontoons at their command, and the soldiers (Pionniere) from Prague
and the firemen from the neighboring towns did not arrive until
evening. Fortunately the water began to fall in the night, and the
next day it had gone down so that it left its terrible work
visible. The Sprudel and the mineral springs were not injured, but,
on the other hand, the water pipes of the bathing establishments
and the gas pipes were completely destroyed.—Illustrirte
Zeitung.

THEATRICAL WATER PLAYS.

In one of the plays at Hengler’s Circus in London a water scene
is introduced, for which purpose the main ring is flooded with
water in a manner which is both striking and interesting.

FLOODING A CIRCUS RING.

The ring is entirely lined with stout macintosh sheeting, and
into this, from two large conduits. 23,000 gallons of water are
poured, the tank being filled to a depth of some 2 ft. in the
remarkably short time of 35 seconds. A steamboat and other small
craft are then launched and the adventures of the heroine then
proceed. She falls overboard, we believe, but is saved after
desperate and amusing struggles. Our engravings, which are from the
Graphic, illustrate the mode of filling the ring with water,
and the steamboat launch.

A THEATRICAL STEAMBOAT.

SCIENCE IN THE THEATER.

In the pretty little hall of the Boulevard des Italiens, at
Paris, a striking exhibition of simulated hypnotism is given every
evening.

This entertainment, which has met with much success, was devised
by Mr. Melies, director of the establishment, which was founded
many years ago by the celebrated prestidigitator whose popular name
(Robert Houdin) it still bears. This performance carries
instruction with it, for it shows how easily the most surprising
phenomena of the pathologic state can be imitated. To this effect,
several exhibitions are given every evening.

Mr. Harmington, a convinced disciple of Mesmer, asks for a
subject, and finds one in the hall. A young artist named Marius
presents himself. Mr. Harmington makes him perform all sorts of
extravagant acts, accompanied with a continuous round of pantomimes
that are rendered the more striking by the supposed state of
somnipathy of the subject. At the moment at which Marius is
finishing his most extraordinary exercises, a policeman suddenly
breaks in upon the stage in order to execute the recent orders
relative to hypnotism. But he himself is subjugated by Mr.
Harmington and thrown down by the vibrations of which the
encephalus of this terrible magnetizer is the center. When the
curtain falls, the representative of authority is struggling
against the catalepsy that is overcoming him.

All the phenomena of induced sleep are successively simulated
with much naturalness by Mr. Jules David, who plays the part of
Marius in this pleasing little performance.

At a certain moment, after skillfully simulated passes made by
the magnetizer, Mr. David suddenly becomes as rigid as a stick of
wood, and falls in pivoting on his heels (Fig. 1). Did not Mr.
Harmington run to his assistance, he would inevitably crack his
skull upon the floor, but the magnetizer stands just behind him in
order to receive him in his arms. Then he lifts him, and places him
upon two chairs just as he would do with a simple board. He places
the head of the subject upon the seat of one of the chairs and the
heels upon that of the other. Mr. David then remains in a state of
perfect immobility. Not a muscle is seen to relax, and not a motion
betrays the persistence of life in him. The simulation is
perfect.

FIG. 1.—CATALEPTIC RIGIDITY.

In order to complete the astonishment of the spectators, Mr.
Harmington seats himself triumphantly upon the abdomen of the
subject and slowly raises his feet and holds them suspended in the
air to show that it is the subject only that supports him, without
the need of any other point of support than the two chairs (Fig.
2).

FIG. 2.—EXPERIMENT ON THE SAME SUBJECT.

Usually, there are plenty of persons ingenuous enough to think
that Mr. David is actually in a cataleptic sleep, one of the
characters of which is cadaveric rigidity.

As Mr. David’s neck is entirely bare, it is not possible to
suppose that the simulator of catalepsy wears an iron corset
concealed beneath his clothing. He has performed a feat of strength
and skill rendered easy by the exercise that he has given to the
muscles occupying the colliciæ of his vertebral
column. This part of the muscular system is greatly developed in
the weakest and least hardy persons. In fact, in order that man may
keep a vertical position and execute an infinite multitude of
motions in which stability is involved, nature has had to give him
a large number of different organs. The muscles of the back are
arranged upon several superposed layers, the vertebral column is
doubly recurved in order that it may have more strength, and,
finally, rachidion nerves issue from each vertebra in order to
regulate the contraction of each muscular fasciculus according to
the requirements of equilibrium. The trick is so easy that we have
seen youths belonging to the Ligue d’Education Physique immediately
imitate Mr. David after seeing him operate but once.

For the sake of those who would like to perform it, we shall add
that Mr. David takes care to bend his body in the form of an arch
in such a way that the convexity shall be beneath. As Mr.
Harmington never fails to place himself in the center of the line
that joins Mr. David’s head and heels, his weight is divided into
two parts, that is to say, 88 pounds on each side of the point of
support. The result is that the stress necessary is less than that
of a strong man of the Halle lifting a bag of wheat to his shoulder
or of an athlete supporting a human pyramid. The force of
contraction of the muscular fibers brought into play in this
experiment is much greater than is commonly believed. In his
lectures on physiology, Milne-Edwards cites some facts that prove
that it may exceed 600 pounds per square inch of section.

FIG. 3.—THE PERFORATE ARM.

The experiment on cadaveric rigidity is followed by others in
insensibility. Mr. David, without wincing, allows a poignard to be
thrust into his arm, which Mr. Harmington has previously
“cataleptized” (Fig. 3). This trick is performed by means of a
blade divided into two parts that are connected by a semicircle.
This process is well known to prestidigitators, but it might be
executed in a genuine manner. In fact, on replacing the poignard by
one of the gold needles used by physicians for acupuncture, it
would be possible to dispense with prestidigitation. Under such
conditions it is possible to transpierce a person’s arm. The pain
is supportable, and consists in the sensation of a prick produced
in the passage of the needle through the skin. As for the muscular
flesh, that is of itself perfectly insensible. The needle, upon the
necessary antiseptic precautions being taken, may traverse the
veins and arteries with impunity, provided that it is not allowed
to remain long enough to bring about the formation of a clot of
coagulated blood (Fig. 4).

FIG. 4.—AN ARM TRANSPIERCED BY A NEEDLE.

We think it of interest to add that it is necessary that the
experiment be performed by a practitioner if one desires to
demonstrate upon himself a very curious physiological fact that has
been known from the remotest antiquity. It has been employed for
several thousand years in Chinese medicine, for opening a passage
for the bad spirits that produce diseases. For some years past a
much more serious use has been made of it in European medicine for
introducing electric currents into the interior of the organism. In
this case the perimeter of the needle is insulated, and the
electricity flows into the organism through the point. We have
several times had these operations performed upon ourselves, and
this permits us to assert that the above mentioned facts are
absolutely true.—La Nature.

NEWER PHYSIOLOGY AND
PATHOLOGY.

By Prof. SAMUEL BELL, M.D.

Physiology has for many decades been a science founded on
experiment, and pathology has been rapidly pressing forward in the
same direction. To read the accounts of how certain conclusions
have been arrived at in the laboratory, by ingenious devices and by
skillful manipulations, is as fascinating as any tale of
adventure.

When the microscope began its work, how discouraging was the
vastness and complexity of the discoveries which it brought to
light; how many years has it been diligently used, and how
uncertain are we still about many of its revelations! But what a
happy conjecture of man, and as proper environment takes place we
may reach better results! Let me give an illustration:

Some thirty years ago, Virchow began his studies and lectures
upon cellular pathology. The enthusiasm which he awakened spread
over the whole medical world. The wonderful attention to detail,
the broad philosophy which signalized his observations, were alike
remarkable. His class room was packed with students from every
country, who thought it no hardship to struggle for a seat at eight
o’clock in the morning. With his blackboard behind him and
specimens of pathology before him, and microscopes coursing upon
railway tracks around the tables which filled the room, he was the
embodiment of the teacher; his highest honor was as discoverer. The
life and importance of the cell, both in health and disease, it has
been his work to discover and to teach. The point of view from
which he has classified tumors is founded on this basis, and
remains the accepted method. The light which he cast upon the
nature of inflammation has not yet been obscured, and while other
phenomena appear, the multiplication of cells and nuclei and the
formation of connective tissue in the process of inflammation will
always call to mind his labors.

To one of Virchow’s pupils, Prof. Recklinghausen, we chiefly owe
our knowledge of the phenomena of diapedesis as a part of the
inflammatory activity. How incredible it seems that masses of
living matter can make their way through the walls of blood vessels
which do not rupture and which have no visible apertures!

Virchow fixed his attention upon the forms and activities of the
cells, their multiplication and degradation, and how they build up
tissues, both healthy and morbid.

To another matter with which, both literally and metaphorically,
the air is filled, we must also make allusion. The existence of
micro-organisms in countless numbers is no new fact, but the
influence they may exert over living tissues has only lately become
the subject of earnest attention. So long as they were not known to
have any practical bearing upon human welfare, they interested
almost nobody, but when, however, it was shown that putrefaction of
meat is due to the agency of the bacterium termo, and the
decomposition of albumen to the bacillus subtilis; when
anthrax in cattle and sheep was found to depend on the bacillus
anthracis, and that in human beings it caused malignant
pustules; when suppuration of wounds was found to be associated
with micrococci; and when it was announced that by a process of
inoculation cattle could be protected against anthrax, and that by
carbolic spray and other well known precautions the suppuration of
wounds could be prevented—all the world lent its ears and
investigation at once began.

Because labors in bacteriology promised to be fruitful in
practical results, the workers speedily became innumerable, and we
are accumulating a wondrous store of facts. How long now is the
list of diseases in which germs make their appearance—in
pneumonia, in endocarditis, in erysipelas, in pyæmia, in
tuberculosis, and so on and so on. One of the most striking
illustrations is the gonococcus of gonorrhœa, whose presence
in and around gives to the pus cells their virulent properties, and
when transferred to the eye works such lamentable mischief. Without
their existence the inoculation of pus in the healthy eye is
harmless; pus bearing the gonococci excites the most intense
inflammation. Similar suppurative action in the cornea is often
caused by infection of cocci. The proof of causation may be found
in the fact that the most effective cure now practiced for such
suppuration is to sterilize them by the actual cautery. Rosenbach
says that he knows six distinct microbes which are capable of
exciting suppuration in man. Their activity may be productive of a
poison, or putrefactive alkaloid, which is absorbed.

There are at present two prominent theories in regard to the
infections which produce disease. The first is based upon chemical
processes, the second upon the multiplication of living organisms.
The chemical theory maintains that after the infectious element has
been received into the body it acts as a ferment, and gives rise to
certain morbid processes, upon the principle of catalysis. The
theory of organisms, or the germ theory, maintains that the
infectious elements are living organisms, which, being received
into the system, are reproduced indefinitely, and excite morbid
processes which are characteristic of certain types of disease.
This latter theory so readily explains many of the facts connected
with the development and reproduction of infectious diseases, that
it has been unqualifiedly adopted by a large number of
investigators. The proofs of this theory had not, however, advanced
beyond the demonstrations of the presence of certain forms of
bacteria in the pathological changes of a very limited number of
infectious diseases, until February, 1882, when Koch announced his
discovery of the tubercle bacillus, since which time nearly every
disease has its supposed microbe, and the race is, indeed, swift in
which the would-be discoverers press forward with new germs for
public favor.

The term bacteria or microbe refers to particles of matter,
microscopic in size, which belong to the vegetable kingdom, where
they are known as fungi. If we examine a drop of stagnant water
under the microscope, amplifying say four hundred diameters, we see
it loaded with minute bodies, some mere points, others slightly
elongated into rods, all actively in motion and in various
positions, a countless confusion. If evaporation now takes place,
all is still. If we now apply moisture, the dried-up granules will
show activity, as though they had not been disturbed.

All these different organisms have become familiar to us under
the generic term bacteria, which is a very unfortunate application,
as it really applies to only a single class of fungi. Cohn calls
them schizomycetes, and makes the following classifications:

The spiro-bacteria, or micrococci, are the simplest of
the fungi, and appear as minute organisms of spherical form. They
multiply by fission, a single coccus forming two, these two
producing four, and so on. They present a variety of appearances
under the microscope. From single isolated specimens (which under
the highest magnifying power present nothing beyond minute points)
you will observe them in pairs, again in fours, or in clusters of
hundreds (forming zoöglea) and still adhering together,
forming chains. When a given specimen is about to divide, it is
seen to elongate slightly, then a constriction is formed, which
deepens until complete fission ensues.

Micrococci possess no visible structure. They consist of a
minute droplet of protoplasm (mycroprotein) surrounded by a
delicate cell membrane. Certain forms are embedded in a capsule
(diameter 0.0008 to 0.0001 millimeter).

These little organisms, when observed in a fluid like blood,
sputum, etc., are found to present very active movements, although
provided with no organs of locomotion.

This Brownian motion is possessed by almost every minute
particle of matter, organic and inorganic, and is not due to any
inherent power of the individual. They are almost omnipresent,
abounding in the air, the earth, the water, are always found in
millions where moist organic matter is undergoing decomposition,
and are associated with the processes of fermentation—in
fact, they are essential to it. The souring of milk succeeds the
multiplication of these germs. Certain varieties are pigmented, and
we observe colonies of chromogenic cocci multiplying upon slices of
boiled potato, eggs, etc., presenting all the colors of the
rainbow. All of these germs are not the cause of disease. Certain
species, however (termed pathogenic), are always associated with
certain diseased conditions.

The bacteria-termo—micro-bacteria—are
slightly elongated, and inasmuch as they multiply by division,
frequently appear coupled together, linked in pairs, and in chains.
They are generally found in putrefying liquids, especially
infusions of vegetable matter. They possess mobility to a
remarkable degree. Observing a field of bacteria-termo under the
microscope, they may be seen actively engaged in twining and
twisting. A flagellum has been demonstrated as attached to one or
both extremities. This is too minute to be generally resolved, even
if it is a common appendage.

Desmo-bacteria (or bacilli) are rod-like organisms,
occurring of various lengths and different thicknesses. In a slide
of the bacillus of tuberculosis and anthrax, we notice at intervals
dots which represent the spores from which, as the rods break up,
future bacilli are developed.

Then we have spiro-bacteria, the spirilla and the
spirochetæ; the former having short open spirals, the latter
long and closely wound spirals. The spirillum, volutans is
often found in drinking water, and in common with some other
specimens of this class is provided with flagellæ, sometimes
at both extremities, which furnish the means of rapid locomotion.
The spiro-bacteria multiply by spores, although little is at
present known of their life history. They frequently are attached
together at their extremities, forming zigzag chains.

We have seen that bacteria differ greatly in appearance from the
elongated dot of the bacterium proper, to the elongated rod or
cylinder of the bacillus, and the long spirals of spiro-bacteria.
It is unfortunate that they are not sufficiently constant in habit
to always attach themselves to one or the other of these genera.
The micrococcus has a habit of elongating at times until it is
impossible to recognize him except as a bacterium; while bacilli,
again, break up until their particles exactly resemble
micrococci.

Bacteria cannot exist without water; certain forms require
oxygen, while others thrive equally well without it; some thrive in
solution of simple salts, while others require albuminoid
material.

Bacteriology, with its relation to the science of medicine, is
of importance to every investigating physician; it covers our
knowledge of the relation of these minute organisms to the
ætiology of disease. What has been gained as to practical
application in the treatment of disease? This question is not
infrequently asked in a sneering manner. We can, in reply, say that
the results are not all in the future. It is encouraging that
results have been attained which have had a very important
practical bearing, and that these complaints come generally from
individuals least acquainted with scientific investigations in
bacteriology.

In the study of the relation of a given bacterium to a certain
disease, it becomes necessary to attend carefully to three
different operations: First, the organism supposed to cause the
disease must be found and isolated. Second, it must be cultivated
through several generations in order that absolute purity may be
secured. Lastly, the germ must be again introduced into a healthy
living being. If the preceding steps be carried out, and the
original disease be communicated by inoculation, and the germs be
again found in the diseased body, we have no alternative; we must
conclude that we have ascertained the cause of the disease. The
importance of being familiar with the ætiology of the disease
before we can expect to combat it with any well-grounded hope of
success is evident.

If the sputum of a phthisical patient be submitted to the
skilled microscopist, he is nearly always able to demonstrate
bacilli, but this goes for very little. Because bacilli are found
in phthisis, it is no more certain that they are the cause of
phthisis than it is certain that cheese mites are the cause of
cheese. Well, suppose we were to inject sputum from a phthisical
person into the lower animal and tuberculosis follows, and then
announce to the profession that we have demonstrated the relation
of the cause and effect between bacilli and phthisis? Why we would
start such an uproar of objections as would speedily convince us
that there was much work yet in the domain of bacteriology.

The scientific investigators would say you have injected with
the sputum into the blood of your unfortunate patient, pus,
morphological elements, and perhaps half a dozen other forms of
bacteria, any one of which is just as likely to produce the disease
as the bacillus you have selected.

The first important step is, first isolate your bacillus. If I
were to take a glass plate, one side of which is coated with a
thick solution of peptonized gelatin, and allow the water to
collect, the gelatinous matter will become solid. If now, with a
wire dipped in some tuberculous matter, I draw a line along the
gelatin, I have deposited at intervals along this line, specimens
of tubercle bacilli. If this plate be now kept at a proper
temperature, after a few days, wherever the bacilli have been
caught, a grayish spot will appear, which, easily seen with the
naked eye, gradually spreads and becomes larger. These spots are
colonies containing thousands of bacilli. Let us return to our
gelatin plate.

We find a spot which answers to the description of a colony of
tubercle bacilli. We now take a minute particle from this colony on
a wire and convey it to the surface of some hardened blood serum in
a test tube. We plug the tube so that no air germs may drop in, and
place it in an incubator at the proper temperature. After several
days, if no contamination be present, a colony of bacilli will
appear around the spot where we sowed the spores. Let us repeat the
process.

Take a particle from this colony, and transfer it to another
tube. This is our second culture. This must be repeated until we
are satisfied that we have secured a pure culture. If this
be carried to the twenty-fifth generation, we may be assured that
there remains no pus, no ptomaines, nothing but the desired
bacilli.

It is a proper material now for inoculation, and if we inoculate
some of the lower animals, for instance the monkey, we produce a
disease identical with phthisis pulmpnalis. Bacteria also afford
peculiar chemical reactions. For example, nitric acid will
discharge all the color from all bacilli artificially dyed with
anilin, except those of tubercle and anthrax. One species is
stained readily with a dye that leaves another unaltered. Thus we
are enabled in the laboratory to determine whether the bacilli
found in sputum, for example, are from tubercle or are the bacteria
of decomposition.

From what I have said of the tubercle bacillus, it would seem
thoroughly demonstrated that it is the cause of tubercle in these
animals. But we must walk cautiously here. These are not human
beings, who know that like results would follow their inoculation.
The animals used by Koch are animals very subject to tubercle.

We must, from the very nature of our environment, be constantly
inhaling these germs as we pass through the wards of our hospitals;
yes, they are floating in the air of our streets and dwellings. It
becomes necessary then for us to inquire: If bacteria cause
disease, in what manner do they produce it? The healthy organism is
always beset with a multitude of non-pathogenic bacteria. They
occupy the natural cavities, especially the alimentary canal. They
feed on the substances lying in their neighborhood, whether brought
into the body or secreted by the tissues. In so doing they set up
chemical changes in their substances. Where the organs are acting
normally these fungi work no mischief. The products of
decomposition thus set up are harmless, or are conveyed out of the
body before they begin to be active.

If bacteria develop to an inordinate degree, if the contents of
organs are not frequently discharged, fermentative processes may be
set up, which result in disease. Bacteria must always multiply and
exist at the expense of the body which they infest, and the more
weakened the vital forces become, the more favorable is the soil
for their development.

Septicæmia is caused by the absorption of the products of
putrefaction, induced before bacteria can multiply inside or
outside the body. Bacteria must find a congenial soil. The
so-called cholera bacillus must gain access to the intestinal tract
before it finds conditions suitable to colonization. It does not
seem to multiply in the stomach or in the blood, but once injected
into the duodenum develops with astonishing rapidity, and the
delicate epithelial cells of the villi become swollen, soften and
break down, exposing the mucosa.

It has been shown that bouillon in which Loeffler’s
diphtheria bacillus has grown, and which has been passed through
unglazed porcelain filters, shows the presence of a poison which is
capable of producing the same results upon inoculation as the pure
culture of the bacillus itself. Zarniko, working upon the same
organism, obtained a number of positive results that led him to
declare this bacillus is the cause of epidemic diphtheria, in spite
of many assertions to the contrary. Chantmesse and Widal record the
results of their work as to what will most easily and effectively
destroy the bacillus of diphtheria.

The only three substances that actually checked and destroyed
its vitality were phenic acid (5 per cent.), camphor (20 per
cent.), olive oil (25 per cent.), in combination. For the last I
substitute glycerine, because this allows the mixture to penetrate
farther into the mucous membrane than oil, the latter favoring a
tendency to pass over the surface. This mixture when heated
separates into two layers, the upper one viscid and forming a sort
of “glycerol,” the lower clear. The latter will completely
sterilize a thread dipped in a pure culture of the diphtheria
bacillus. Corrosive sublimate was not examined because in strong
enough doses it would be dangerous and in weaker ones it would be
useless.

The facts obtained in regards to the streptococcus of erysipelas
are reported as follows: That both chemical and experimental
evidence teach the extreme ease of a renewed attack of the disease;
that it is possible to kill guinea pigs by an intoxication when
they are immune to an inoculation of the culture in ordinary
quantities. And this latter fact should warn experimenters trying
to obtain immunity in man by the inoculation of non-pathogenic
bacteria, because the same results may be reached.

A new theory in regard to fevers and the relation of
micro-organisms is suggested by Roussy, viz.: That it is a
fermentation produced by a diastase or soluble ferment found in all
micro-organisms and cells, and which they use in attacking and
transforming matter, either inside their substance or without
it.

The resemblance of the malaria parasite to that of recurrent
fever is noted in the work of Sacharoff. He states that there
exists in the blood of those suffering from recurrent fever a
hæmatozoon, which is most prominent after the fever has begun
to fall, when it is of enormous proportions, twenty or more
diameters of a red blood corpuscle, although smaller ones may still
be found. The parasite consists of a delicate amœboid body
containing a multitude of dark, round, uniform, sharply outlined,
movable granules. Besides these, the protoplasm contains a
generally grayish homogeneous nucleus as large as one or two red
blood corpuscles. The protoplasm sends out pseudopodia (with
granules), which sometimes separate and appear as small delicate
pieces of protoplasm. They vary in size, and are often swallowed by
the red blood corpuscles in which they grow, and finally develop
into the above mentioned amœboid bodies.

Prof. J. Lewis Smith has made a great many autopsies of children
dead from cholera infantum, and almost invariably found the stomach
and liver in a comparatively healthy condition. Ganghen, who has
given this subject considerable study, denies the existence of any
specific germ in the summer diarrhea of infants, but claims to have
found three different germs in the intestines of children suffering
from cholera infantum, each producing a chemical poison which is
capable of producing vomiting, purging, and even death. A great
variety of germs are found in drinking water, and no doubt
countless numbers are taken into the digestive tract, and the
principal reason why pathological conditions do not occur more
frequently is on account of the germicidal qualities of the gastric
juice.

The comma bacillus of Koch, and the typhoid fever germ of
Eberth, are especially destroyed in normal gastric juice. When the
germs are very numerous, they run the gauntlet of the stomach (as
the gastric juice is secreted only during digestion); and once in
the alkaline intestinal canal they are capable of setting up
disease, other conditions contributing—ill health, deranged
digestion, etc.

Mittnam has made a study of bacteria beneath the nails, and
reports, after examining persons following different occupations,
having found numerous varieties of micro-organisms; which are
interesting from a scientific standpoint relative to the importance
of thoroughly cleansing the hands before undertaking any surgical
procedure. He found, out of twenty-five experiments, 78 varieties
of bacteria, of which 36 were classed as micrococci, 21 diplococci,
18 rods, 3 sarcinæ, and 1 yeast. Cooks, barbers, waiters,
etc., were examined.

The blood, defibrinated and freshly drawn, has marked germicidal
action; for bacteria its action is decidedly deadly, even hours
after it has been drawn from the body. Especially were anti-germic
qualities noticed upon pathogenic bacteria. Buchner put the bacilli
of anthrax in a quantity of blood, and in two hours the number was
reduced from 4,800 to 56, and in three hours only 3 living bacteria
remained. Other bacteria were experimented upon in blood with
similar results, but the destruction of the organism from
putrefaction was much less marked, and on some varieties the blood
had little or no action.

It is not the object of these remarks to even give a
résumé of the status præsens of
bacteriology, but simply to stimulate thought in that direction.
The claims of some of the ultra-bacteriologists may never be
realized, but enough has been accomplished to revolutionize the
treatment of certain diseases, and the observing student will do
well to keep his eye on the microbe, as it seems from the latest
investigations that its star is in the ascendant. And who can
prognosticate but that in the next decade an entire revolution in
the ætiology and treatment of many diseases may take
place?

Detroit, Mich.

THE COMPOSITION OF KOCH’S
LYMPH.

WHAT PROFESSOR KOCH SAYS IT IS, AND WHAT IT CAN DO.

(By Cable to the Medical Record.)

BERLIN, January 15, 1891.

The curiosity to know the composition of the famous lymph has
been gratified by the publication to-day of an article by Professor
Koch on the subject. In the following, as will be seen, he
reaffirms his original convictions and acknowledges the valuable
assistance he has received from those who have used his fluid, and
thus helped him in the accumulation of experience.

Professor Koch says: Two months ago I published the results of
my experiments with the new remedy for tuberculosis, since which
time many physicians who received the preparation have been enabled
to become acquainted with its properties through their own
experiments. So far as I have been able to review the statements
published and the communications received by letter, my predictions
have been fully and completely confirmed. The general consensus of
opinion is that the remedy has a specific action upon tubercular
tissues, and is, therefore, applicable as a very delicate and sure
reagent for discovering latent and diagnosing doubtful tuberculous
processes. Regarding the curative effects of the remedy, most
reports agree that, despite the comparatively short duration of its
application, many patients have shown more or less pronounced
improvement. It has been affirmed that in not a few cases even a
cure has been established. Standing quite by itself is the
assertion that the remedy may not only be dangerous in cases which
have advanced too far—a fact which may forthwith be
conceded—but also that it actually promotes the tuberculous
process, being therefore injurious.

During the past six weeks I myself have had opportunity to bring
together further experiences touching the curative effects and
diagnostic application of the remedy in the cases of about one
hundred and fifty sufferers from tuberculosis of the most varied
types in this city and in the Moabit Hospital.

I can only say that everything I have latterly seen accords with
my previous observations. There has been nothing to modify in what
I before reported. As long as it was only a question of proving the
accuracy of my indications, it was needless for any one to know
what the remedy contained or whence it was derived. On the
contrary, subsequent testing would necessarily be more unbiased,
the less people knew of the remedy itself. Now, after sufficient
confirmatory testing, the importance of the remedy is proved, my
next task is to extend my study of the remedy beyond the field
where it has hitherto been applied, and if possible to apply the
principle underlying the discovery to other diseases.

This task naturally demands a full knowledge of the remedy. I
therefore consider that the time has arrived when the requisite
indications in this direction shall be made. This is done in what
follows.

Before going into the remedy itself, I deem it necessary for the
better understanding of its mode of operation to state briefly the
way by which I arrived at the discovery. If a healthy guinea pig be
inoculated with the pure cultivation of German Kultur of tubercle
bacilli, the wound caused by the inoculation mostly closes over
with a sticky matter, and appears in its early days to heal. Only
after ten to fourteen days a hard nodule presents itself, which,
soon breaking, forms an ulcerating sore, which continues until the
animal dies. Quite a different condition of things occurs when a
guinea pig already suffering from tuberculosis is inoculated. An
animal successfully inoculated from four to six weeks before is
best adapted for this purpose. In such an animal the small
indentation assumes the same sticky covering at the beginning, but
no nodules form. On the contrary, on the day following, or the
second day after the inoculation, the place where the lymph is
injected shows a strange change. It becomes hard and assumes a
darker coloring, which is not confined to the inoculation spot, but
spreads to the neighboring parts until it attains a diameter of
from 0.05 to 1 cm.

In a few days it becomes more and more manifest that the skin
thus changed is necrotic, finally falling off, leaving a flat
ulceration which usually heals rapidly and permanently without any
involvement of the adjacent lymphatic glands. Thus the injected
tubercular bacilli quite differently affect the skin of a healthy
guinea pig from one affected with tuberculosis. This effect is not
exclusively produced with living tubercular bacilli, but is also
observed with the dead bacilli, the result being the same whether,
as I discovered by experiments at the outset, the bacilli are
killed by a somewhat prolonged application of a low temperature or
boiling heat or by means of certain chemicals. This peculiar fact I
followed up in all directions, and this further result was
obtained—that killed pure cultivations of tubercular bacilli,
after rinsing in water, might be injected in great quantities under
healthy guinea pig’s skin without anything occurring beyond local
suppuration. Such injections belong to the simplest and surest
means of producing suppurations free from living bacteria.

Tuberculous guinea pigs, on the other hand, are killed by the
injection of very small quantities of such diluted cultivations. In
fact, within six to forty-eight hours, according to the strength of
the dose, an injection which is not sufficient to produce the death
of the animal may cause extended necrosis to the skin in the
vicinity of the place of injection. If the dilution is still
further diluted until it is scarcely visibly clouded, the animals
inoculated remain alive and a noticeable improvement in their
condition soon supervenes. If the injections are continued at
intervals of from one to two days, the ulcerating inoculation wound
becomes smaller and finally scars over, which otherwise it never
does; the size of the swollen lymphatic glands is reduced, the body
becomes better nourished, and the morbid process ceases, unless it
has gone too far, in which case the animal perishes from
exhaustion. By this means the basis of a curative process against
tuberculosis was established.

Against the practical application of such dilutions of dead
tubercle bacilli there presented itself the fact that the tubercle
bacilli are not absorbed at the inoculation points, nor do they
disappear in another way, but for a long time remain unchanged, and
engender greater or smaller suppurative foci. Anything, therefore,
intended to exercise a healing effect on the tuberculous process
must be a soluble substance which would be liberated to a certain
extent by the fluids of the body floating around the tubercle
bacilli, and be transferred in a fairly rapid manner to the juices
of the body; while the substance producing suppuration apparently
remains behind in the tubercular bacilli, or dissolves but very
slowly. The only important point was, therefore, to induce outside
the body the process going on inside, if possible, and to extract
from the tubercular bacilli alone the curative substance. This
demanded time and toil, until I finally succeeded, with the aid of
a forty to fifty per cent. solution of glycerine, in obtaining an
effective substance from the tubercular bacilli. With the fluid so
obtained I made further experiments on animals, and finally on
human beings. These fluids were given to other physicians to enable
them to repeat the experiments.

The remedy which is used in the new treatment consists of a
glycerine extract, derived from the pure cultivation of tubercle
bacilli. Into the simple extract there naturally passes from the
tubercular bacilli, besides the effective substance, all the other
matter soluble in fifty per cent. glycerine.

Consequently, it contains a certain quantity of mineral salts,
coloring substances, and other unknown extractive matters. Some of
these substances can be removed from it tolerably easily. The
effective substance is insoluble in absolute alcohol. It can be
precipitated by it, though not, indeed, in a pure condition, but
still combined with the other extractive matter. It is likewise
insoluble in alcohol. The coloring matter may also be removed,
rendering it possible to obtain from the extract a colorless, dry
substance containing the effective principle in a much more
concentrated form than the original glycerine solution. For
application in practice this purification of the glycerine extract
offers no advantage, because the substances so eliminated are
unessential for the human organism. The process of purification
would make the cost of the remedy unnecessarily high.

Regarding the constitution of the more effective substances,
only surmises may for the present be expressed. It appears to me to
be derivative from albuminous bodies, having a close affinity to
them. It does not belong to the group of so-called toxalbumins,
because it bears high temperatures, and in the dialyzer goes easily
and quickly through the membrane. The proportion of the substance
in the extract to all appearance is very small. It is estimated at
fractions of one per cent., which, if correct, we should have to do
with a matter whose effects upon organisms attacked with
tuberculosis go far beyond what is known to us of the strongest
drugs.

Regarding the manner in which the specific action of the remedy
on tuberculous tissue is to be represented, various hypotheses may
naturally be put forward. Without wishing to affirm that my view
affords the best explanation, I represent the process myself in the
following manner:

The tubercle bacilli produced when growing in living tissues,
the same as in artificial cultivations, contain substances which
variously and notably unfavorably influence living elements in
their vicinity. Among these is a substance which in a certain
degree of concentration kills or so alters living protoplasm that
it passes into a condition that Weigert describes as coagulation
necrosis. In tissue thus become necrotic the bacillus finds such
unfavorable conditions of nourishment that it can grow no more and
sometimes dies.

This explains the remarkable phenomenon that in organs newly
attacked with tuberculosis, for instance in guinea pigs’ spleen and
liver, which then are covered with gray nodules, numbers of bacilli
are found, whereas they are rare or wholly absent when the
enormously enlarged spleen consists almost entirely of whitish
substance in a condition of coagulation necrosis, such as is often
found in cases of natural death in tuberculous guinea pigs. The
single bacillus cannot, therefore, induce necrosis at a great
distance, for as soon as necrosis attains a certain extension the
growth of the bacillus subsides, and therewith the production of
the necrotizing substance. A kind of reciprocal compensation thus
occurs, causing the vegetation of isolated bacilli to remain so
extraordinarily restricted, as, for instance, in lupus and
scrofulous glands.

In such cases the necrosis generally extends only to a part of
the cells, which then, with further growth, assume the peculiar
form of riesen zelle, or giant cells. Thus, in this interpretation,
follow first the explanation Weigert gives of the production of
giant cells.

If now one increased artificially in the vicinity of the
bacillus the amount of necrotizing substance in the tissue, the
necrosis would spread a greater distance. The conditions of
nourishment for the bacillus would thereby become more unfavorable
than usual.

In the first place the tissue which had become necrotic over a
large extent would decay and detach itself, and where such were
possible would carry off the inclosed bacilli and eject them
outwardly, so far disturbing their vegetation that they would much
more speedily be killed than under ordinary circumstances.

It is just in looking at such changes that the effect of the
remedy appears to consist. It contains a certain quantity of
necrotizing substance, a correspondingly large dose of which
injures certain tissue elements even in a healthy person, and
perhaps the white blood corpuscles or adjacent cells, thereby
producing fever and a complication of symptoms, whereas with
tuberculous patients a much smaller quantity suffices to induce at
certain places, namely, where tubercle bacilli are vegetating and
have already impregnated the adjacent region with the same
necrotizing matter, more or less extensive necrosis of the cells,
with the phenomena in the whole organism which result from and are
connected with it.

For the present, at least, it is impossible to explain the
specific influence which the remedy, in accurately defined doses,
exercises upon tuberculous tissue, and the possibility of
increasing the doses with such remarkable rapidity, and the
remedial effects which have unquestionably been produced under not
too favorable circumstances.

Of the consumptive patients whom he described as temporarily
cured, two have been returned to the Moabit Hospital for further
observation.

No bacilli have appeared in their sputum for the past three
months, and their phthisical symptoms have gradually and completely
disappeared.

CAN WE SEPARATE ANIMALS FROM
PLANTS?

By ANDREW WILSON.

One of the plainest points connected with the study of living
things is the power we apparently possess of separating animals
from plants. So self-evident appears this power that the popular
notion scoffs at the idea of science modestly disclaiming its
ability to separate the one group of living beings from the other.
Is there any danger of confusing a bird with the tree amid the
foliage of which it builds its nest, or of mistaking a cow for the
grass it eats? These queries are, of course, answerable in one way
only. Unfortunately (for the querists), however, they do not
include or comprehend the whole difficulty. They merely assert,
what is perfectly true, that we are able, without trouble, to mark
off the higher animals from the higher plants. What science
inquires is, whether we are able to separate all animals
from all plants, and to fix a definite boundary line, so as
to say that all the organisms on the one side of the line are
assuredly animals, while all the others on the opposite side of the
line may be declared to be truly plants. It is exactly this task
which science declares to be among the impossibilities of
knowledge. Away down in the depths of existence and among the
groundlings of life the identity of living things becomes of a
nature which is worse than confusing, and which renders it a futile
task to attempt to separate the two worlds of life. The
hopelessness of the task, indeed, has struck some observers so
forcibly that they have proposed to constitute a third
kingdom—the Regnum Protisticum—between the
animal and the plant worlds, for the reception of the host of
doubtful organisms. This third kingdom would resemble the casual
ward of a workhouse, in that it would receive the waifs and strays
of life which could not find a refuge anywhere else.

A very slight incursion into biological fields may serve to show
forth the difficulties of naturalists when the task of separating
animals from plants is mooted for discussion. To begin with, if we
suppose our popular disbeliever to assert that animals and plants
are always to be distinguished by shape and form, it is easy enough
to show him that here, as elsewhere, appearances are deceptive.
What are we to say of a sponge, or a sea anemone, of corals, of
zoophytes growing rooted from oyster shells, of sea squirts, and of
sea mats? These, each and all of them, are true animals, but they
are so plant-like that, as a matter of fact, they are often
mistaken by seaside visitors for plants. This last remark holds
especially true of the zoophytes and the sea mats. Then, on the
other hand, we can point to hundreds of lower plants, from the
yeast plant onward, which show none of the ordinary features of
plant life at all. They possess neither roots, stems, branches,
leaves, nor flowers, so that on this first count of the indictment
the naturalist gains the day.

Power of movement, to which the popular doubter is certain to
appeal, is an equally baseless ground of separation. For all the
animals I have above named are rooted and fixed, while many true
plants of lower grade are never rooted at all. The yeast plant, the
Algæ that swarm in our ponds, and the diatoms that
crowd the waters, exemplify plants that are as free as animals; and
many of them, besides, in their young state especially (e.g., the
seaweeds), swim about freely in the water as if they were roving
animalcules. On the second count, also, science gains the day;
power of motion is no legitimate ground at all for distinguishing
one living being as an animal, while absence of movement is
similarly no reason for assuming that the fixed organism must of
necessity be a plant. Then comes the microscopic evidence. What can
this wonder glass do in the way of drawing boundary lines betwixt
the living worlds? The reply again is disappointing to the doubter;
for the microscope teaches us that the tissues of animals and
plants are built upon kindred lines. We meet with cells and fibers
in both. The cell is in each case the primitive expression of the
whole organism. Beyond cells and fibers we see the wonderful living
substance, protoplasm, which is alike to our senses in the
two kingdoms, although, indeed, differing much here and there in
the results of its work. On purely microscopic grounds, we cannot
separate animals from plants. There is no justification for rigidly
assuming that this is a plant or that an animal on account of
anything the microscope can disclose. A still more important point
in connection with this protoplasm question consists in the fact
that as we go backward to the beginnings of life, both in animals
and plants, we seem to approach nearer and nearer to an identity of
substance which baffles the microscope with all its powers of
discernment. Every animal and every plant begins existence as a
mere speck of this living jelly. The germ of each is a protoplasm
particle, which, whatever traces of structure it may exhibit, is
practically unrecognizable as being definitely animal or plant in
respect of its nature. Later on, as we know, the egg or germ shows
traces of structure in the case of the higher animals and plants;
while even lowly forms of life exhibit more or less characteristic
phases when they reach their adult stage. But, of life’s
beginnings, the microscope is as futile as a kind scientific
touchstone for distinguishing animals from plants as is power of
movement, or shape, or form.

A fourth point of appeal in the matter is found within the
domain of the chemist. Chemistry, with its subtile powers of
analysis, with its many-sided possibilities of discovering the
composition of things, and with its ability to analyze for us even
the light of the far distant stars, only complicates the
difficulties of the biologist. For, while of old it was assumed
that a particular element, nitrogen, was peculiar to animals, and
that carbon was an element peculiar to plants, we now know that
both elements are found in animals, just as both occur in plants.
The chemistry of living things, moreover, when it did grow to
become a staple part of science, revealed other and greater
anomalies than these. It showed that certain substances which were
supposed to be peculiar to plants, and to be made and manufactured
by them alone, were also found in animals. Chlorophyl is the green
coloring matter of plants, and is, of course, a typical product of
the vegetable world; yet it is made by such animals as the hydra of
the brooks and ponds, and by many animalcules and some worms.
Starch is surely a typical plant product, yet it is undoubtedly
manufactured, or at least stored up, by animals—a work
illustrated by the liver of man himself, which occasionally
produces sugar out of its starch.

Again, there is a substance called cellulose, found well
nigh universally in plants. Of this substance, which is akin to
starch, the walls or envelopes of the cells of plant tissues are
composed. Yet we find those curious animals, the sea squirts, found
on rocks and stones at low-water mark, manufacturing cellulose to
form part and parcel of the outer covering of their sac-like
bodies. Here it is as if the animal, like a dishonest manufacturer,
had infringed the patent rights of the plant. On the fourth count,
then—that of chemical composition—the verdict is that
nothing that chemistry can teach us may serve definitely, clearly,
and exactly to set a boundary line or to erect a partition wall
between the two worlds of life. There yet remains for us to
consider a fifth head—that of the food.

In the matter of the feeding of the two great living worlds we
might perchance light upon some adequate grounds for making up the
one kingdom from the other. What the consideration of form,
movement, chemical composition, and microscopic structure could not
effect for us in this way, it might be supposed the investigation
of the diet of animals and plants would render clear. Our hopes of
distinguishing the one group from the other by reference to the
food on which animals and plants subsist are, however, dashed to
the ground; and the diet question leaves us, therefore, when it has
been discussed, in the same quandary as before.

Nevertheless, it is an interesting story, this of the nutrition
of animals and plants. A large amount of scientific information is
to be gleaned from such a study, which may very well be commenced
by our having regard to the matters on which a green plant
feeds. I emphasize the word “green,” because it so happens that
when a plant has no chlorophyl (as green color is named in the
plant world) its feeding is of diverse kind to that which a green
plant exhibits. The mushroom or other fungus may be taken as an
illustration of a plant which represents the non-green race, while
every common plant, from a bit of grass to an oak tree, exemplifies
the green-bearing order of the vegetable tribes.

Suppose we were to invite a green plant to dinner, the
menu would have to be very differently arranged from that
which would satisfy a human or other animal guest. The soup would
be represented for the plant’s delectation by water, the fish by
minerals, the joint by carbonic acid gas, and the dessert by
ammonia. On these four items a green plant feeds, out of them it
builds up its living frame. Note that its diet is of inorganic or
non-living matter. It derives its sustenance from soil and air, yet
out of these lifeless matters the green plant elaborates and
manufactures its living matter, or protoplasm. It is a more
wonderful organism than the animal, for while the latter can only
make new protoplasm when living matter is included in its food
supply, the green plant, by the exercise of its vital chemistry,
can transform that which is not living into that which is
life-possessing.

The green plant in other words, raises non-living into living
matter, while the animal can only transform living matters into its
like. This is why the plant is called a constructive organism,
while the animal is, contrariwise, named a destructive one. The
result of the plant’s existence is to build up, that of the
animal’s life is to break down its substance, as the result of its
work, into non-living matter. The animal’s body is, in fact,
breaking down into the very things on which the green plant feeds.
We ourselves are perpetually dissipating our substance in our acts
of life and work into the carbonic acid, water, ammonia, and
minerals on which plants feed. We “die daily” in as true a sense as
that in which the apostle used the term. And out of the debris of
the animal frame the green plant builds up leaf and flower, stein
and branch, and all the other tokens of its beauty and its
life.

If, then, an animal can only live upon living matter—that
is to say on the bodies of other animals or of plants—with
water, minerals and oxygen gas from the air thrown in to boot, we
might be tempted to hold that in such distinctive ways and works we
had at last found a means of separating animals from plants.
Unfortunately, this view may be legitimately disputed and rendered
null and void, on two grounds. First of all, the mushrooms and
their friends and neighbors, all true plants, do not feed as do the
green tribes. And secondly, many of the green plants themselves can
be shown to have taken very kindly to an animal mode of diet.

A mushroom, thus, because it has no green color, lives upon
water, oxygen, minerals, and organic matter. You can only grow
mushrooms where there is plenty of animal matter in a state of
decay, and as for the oxygen, they habitually inhale that gas as if
they were animals. Non-green plants thus want a most characteristic
action of their green neighbors. For the latter in daylight take in
the carbonic acid gas, which is composed of carbon and oxygen.
Under the combined influence of the green color and the light, they
split up the gas into its two elements, retaining the carbon for
food and allowing the oxygen to escape to the atmosphere. Alas!
however, in the dark our green plant becomes essentially like an
animal as regards its gas food, for then it is an absorber of
oxygen, while it gives off carbonic acid. If to take in carbonic
acid and to give out oxygen be held to be a feature characteristic
of a plant, it is one, as has been well said, which disappears with
the daylight in green plants, and which is not witnessed at all in
plants that have no green color.

So far, we have seen that not even the food of plants and
animals can separate the one kingdom of life from the other. The
mushroom bars the way and the green plant’s curious behavior by
night and by day respectively, in the matter of its gas food, once
more assimilates animal life and plant life in a remarkable manner.
Still more interesting is the fact, already noticed, that even
among the green tribes there are to be found many and various
lapses from the stated rules of their feeding. Thus what are we to
say of the parasitic mistletoe, which, while it has grown leaves of
its own, and can, therefore, obtain so much carbon food from the
air on its own account, nevertheless drinks up the sap of the oak
or apple which forms its host, and thus illustrates the spectacle
of a green plant feeding like an animal, on living matter? Or, what
may we think of such plants as the sundew, the Venus’ fly trap, the
pitcher plants, the side saddle plants, the butterworts and
bladderworts, and others of their kind, which not only capture
insects, often by ingenious and complex lures, but also digest the
animal food thus captured? A sundew thus spreads out its lure in
the shape of its leaf studded with sensitive tentacles, each capped
by a glistening drop of gummy secretion. Entangled in this
secretion, the fly is further fixed to the leaf by the tentacles
which bend over it and inclose it in their fold. Then is poured out
upon the insect’s body a digestive acid fluid, and the substance of
the dissolved and digested animal is duly absorbed by the plant. So
also the Venus’ fly trap captures insects by means of its leaf,
which closes upon the prey when certain sensitive hairs have given
the signal that the animal has been trapped. Within the leaf the
insect is duly digested as before, and its substance applied to the
nutrition of the plant. Such plants, moreover, cannot flourish
perfectly unless duly supplied with their animal food. Such
illustrations of exceptions to the rule of green plant feeding
simply have the effect of abolishing the distinctions which the
diet question might be supposed to raise between animals and
plants. We may return to the sundews and other insect catchers;
meanwhile, I have said enough to show that to the question, “Can we
separate animals from plants?” a very decided negative reply must
be given. Life everywhere exhibits too many points of contact to
admit of any boundary line being drawn between the two great groups
which make up the sum total of organic
existence.—Illustrated London News.

THE RECOVERY OF SILVER AND GOLD
FROM PLATING AND GILDING SOLUTIONS.

In view of the rapid development and extension of the methods of
electro-plating with silver and gold, and of the large amount of
spent liquors containing silver or gold thus produced, it has long
been desirable to find methods by which these metals can be
recovered from the spent liquors. The processes hitherto adopted
generally necessitate the tedious and unpleasant evaporation of the
cyanide liquors, or else involve a series of chemical operations
which are somewhat difficult to carry out, so that actually the
used-up baths are sold to some firm which undertakes this recovery
as a particular branch of its business.

A process invented by Stockmuir and Fleischmann, and worked out
by them in the chemical laboratory of the Bavarian Industrial
Museum, is, however, exceedingly simple, and is employed in many
establishments.

In order to remove silver from a potassium cyanide silver
solution, it is only necessary to allow a clean piece of plate zinc
to remain in the liquid for two days; even better results are
obtained by the use of iron conjointly with the zinc. In the first
case, the silver often adheres firmly to the zinc, while in the
second it always separates out as a powder. It is then only
necessary to wash the precipitated powder, which usually contains
copper (since spent silver solutions always contain copper), dry
it, and then dissolve it in hot concentrated sulphuric acid, water
being added, and the dissolved silver precipitated by strips of
copper. The silver thus obtained is perfectly pure. If the amount
of copper present is only small, it can usually be removed by
fusing the precipitated powder with a little niter and borax.

In this way a spent silver bath was found to contain per
liter

The presence of silver could not be qualitatively ascertained in
the residual liquor.

Although sheet zinc, or zinc and iron sheets, serve so well for
the precipitation of silver, they cannot be employed for the
recovery of gold. The latter separates out in such a case very
incompletely and as a firmly adhering lustrous film in the zinc. On
the other hand, finely divided zinc, the so-called zinc dust, is an
excellent substance to employ for precipitating gold quantitatively
and in the form of powder from spent cyanide liquors. When zinc
dust is added to a spent gold bath and the liquid periodically
stirred or shaken, all the gold is precipitated in two or three
days. The amount of zinc to be added naturally depends on the
quantity of gold present. Freshly prepared gold baths for gilding
in the cold contain on the average 3.5 grms. gold per liter, while
those used for the hot process contain 10.75 grms. To precipitate
all the gold in the original bath, 1.74 grms. or 0.37-0.5 grms.
zinc dust would be necessary, and, of course, a much smaller
quantity would be sufficient for the spent liquors. Since the
precipitation takes place more rapidly when an excess of zinc dust
is present, it is generally advisable to add ¼ or at the
most ½ kilo, of zinc dust to every 100 liters of
solution.

The precipitated gold, which contains zinc dust and usually
silver and copper, is washed, freed from zinc by hydrochloric acid,
and then from silver and copper by nitric acid and thus obtained
pure.

A spent bath treated in this way gave the following amounts of
gold per liter:

The presence of gold in the residual cyanide solution could not
be qualitatively detected. The potassium cyanide of the solutions
obtained by this process should be converted into ferrocyanide by
heating with ferrous sulphate and milk of lime, since this
substance is not poisonous and can therefore be got rid of without
danger. It would, however, be more economical and, considering the
large amount of cyanide present, more profitable to work it up into
Prussian blue.

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