SCIENTIFIC AMERICAN SUPPLEMENT NO. 365

NEW YORK, DECEMBER 30, 1882.

Scientific American Supplement. Vol. XIV., No. 365.

Scientific American established 1845

Scientific American Supplement, $5 a year.

Scientific American and Supplement, $7 a year.

APPARATUS FOR MANUFACTURING GASEOUS OR AERATED BEVERAGES.

The apparatus employed at present for making gaseous
beverages are divided into two classes—intermittent apparatus
based on chemical compression, and continuous ones
based on mechanical compression.

The first are simple in appearance and occupy small space,
but their use is attended with too great inconveniences and
losses to allow them to be employed in cases where the
manufacture is of any extent, so the continuous apparatus
are more and more preferred by those engaged in the industry.

Continuous apparatus, however, other than those that we
now propose to occupy ourselves with, are not without some
defects, for the gas is produced in them intermittingly and
at intervals, and more rapidly than it is used, thus necessitating
the use of a gasometer, numerous and large washers,
complicated piping, and, besides, of an acid cock.

To get rid of such drawbacks, it became necessary to seek
a means of rendering the production of the gas continuous,
and of regulating it automatically without the aid of the
operator. Mr. Mondollot has obtained such a result
through a happy modification of the primitive system of the
English engineer Bramah. He preserves the suction and
force pump but, while applying it to the same uses, he likewise
employs it, by the aid of a special arrangement, so as
to distribute the sulphuric acid automatically over the chalk
in the generator, and to thus obtain a regular and continuous
disengagement of carbonic acid gas. The dangers and
difficulties in the maneuver of an acid cock are obviated, the
gasometer and its cumbersome accessories are dispensed
with, and the purification is more certain, owing to the regularity
with which the gas traverses the washers.

APPARATUS FOR MANUFACTURING GASEOUS BEVERAGES.

In the accompanying plate we have figured three types of
these apparatus. The first that we shall describe is arranged
for the use of bicarbonate of soda. This apparatus
consists (1) of a generator, C D, (2) of a double washer G G,
(3) of a suction pump, P, and (4) of a saturator, S (See Figs
1 to 9).

The Generator.—This consists of a cylindrical leaden
receptacle, D, on the bottom of which rests a leaden bell containing
apertures, c, at its base. A partition, c, into which
is screwed a leaden tube, C, containing apertures divides the
interior of the bell into two compartments. The upper of
these latter is surmounted by a mouth, B, closed by a clamp,
and through which the bicarbonate of soda is introduced.
A definite quantity of water and sulphuric acid having been
poured into the receptacle, D, a level tends to take place between
the latter and the bell, C, the liquid passing through

the apertures. But the acidulated water, coming in contact
with the soda, sets free carbonic acid gas, which, having no
exit, forces the water back and stops the production of gas
until the apparatus is set in motion. At this moment, the
suction of the pump causes a new inflow of acidulated water
upon the soda, from whence another disengagement of gas,
and then a momentary forcing of the water, whose level
thus alternately rises and falls and causes a continuous production
of gas proportionate with the suction of the pump.

The consumption of soda and acid is about 2 kilogrammes
each for charging 100 siphons or 150 bottles. The bicarbonate
is known to be used up when the liquid in the generator
is seen to descend to the bottom of the water level, n,
fixed to the vessel, D.

The Washer (Figs 1 and 4)—The gas, on leaving the
generator, enters the washer through a bent copper pipe, R.
The washer is formed of two ovoid glass flasks G G, mounted
on a bronze piece, L, to which they are fixed by screw rings, l,
of the same metal. The two flasks, G G, communicate with
each other only through the tinned-copper tube q, which is
held in the mounting q, of the same metal. This latter is
screwed into the piece, L, and contains numerous apertures,
through which the gas coming in from the pipe, R, passes to
reach the upper flask, G. The gas is washed by bubbling
up through water that has been introduced through the cock, R.
After it has traversed both flasks, it escapes through the
copper pipe, p, into which it is sucked by the pump, P.

The Pump (Figs 1, 5 and 6)—This consists of a cylindrical
chamber, P, of bronze, bolted to a bracket on the frame,
and cast in a piece, with the suction valve chamber, P, in
which the valve, p, plays. It is surmounted by the distributing
valve chamber P². This latter is held by means
of two nuts screwed on to the extremity of the rods, p³,
connected with the shell, E, of the distributing-cock, E. In the
shell, E, terminates, on one side, the pipe, p, through which
enters the gas from the washer, and, on the other, the pipe i,
that communicates with a feed-reservoir not shown in the
cuts. The cock E, permits of the simultaneous regulation
of the entrance of the gas and water. Its position is shown
by an index e, passing over a graduated dial, e. From the
distributing valve chamber, P² the pipe, s, leads the mixture
of water and gas under pressure into

The Saturator, S (Figs 1, 7 and 9)—This consists of a large
copper vessel, s, affixed to the top of the frame through the
intermedium of a bronze collar h, and a self closing bottom
H. This latter is provided with two pipes, one of which, s,
leads the mixture of water and carbonic acid forced by the
pump, and the other, b, communicates with the siphons or
bottles to be filled. The pipe, b, is not affixed directly to the
bottom, but is connected therewith through the intermedium

of a cock, r. The object of the broken form of this pipe is to
cause the pressure to act according to the axis of the screw,
r, which is maneuvered by the key, r².

The water under pressure, having been forced into the
vessel, S, is submitted therein to an agitation that allows it
to dissolve a larger quantity of gas. Such agitation is produced
by two pairs of paddles, J J, mounted at the extremity
of an axle actuated by the wheel, A, through the intermedium
of gearings, g and g.

The course of the operation in the saturator may be followed
by an inspection of the water level, n, seen at the front
and side in Figs. 2 and 3. This apparatus, in which the
pressure reaches 4 to 6 atmospheres in the manufacture of
Seltzer water or gaseous lemonade in bottles, and from 10
to 12 atmospheres in that of Seltzer water in siphons, is
provided also with a pressure gauge, m, and a safety valve,
both screwed, as is also the tube, n², into a sphere, S, on the
top of the saturator.

Apparatus for Using Carbonate of Lime (Figs 2, 3,
and 10)—When chalk is acted upon by sulphuric acid, there is
formed an insoluble sulphate which, by covering the chalk,
prevents the action of the acid from continuing if care be
not taken to constantly agitate the materials. This has led
to a change in the arrangement of the generator in the
apparatus designed for the use of chalk.

It consists in this case of a leaden vessel, D, having a
hemispherical bottom set into a cylindrical cast iron base, K,
and of an agitator similar to that shown in Fig. 11, for
keeping the chalk in suspension in the water. These latter
materials are introduced through the mouth, B (Fig. 3).
Then a special receptacle, C, of lead, shown in detail in
Fig. 10, and the cock, c, of which is kept closed, is filled with
sulphuric acid. The acid is not introduced directly into the
vessel, C, but is poured into the cylinder, C, whose sides contain
numerous apertures which prevent foreign materials
from passing into the siphon tube c, and obstructing it.

To put the apparatus in operation, the acid cock, c, is
opened and the wheel, A, is turned, thus setting in motion
both the pump piston, P, and the agitator, within S and D.
Then the play of the pump produces a suction in the
washers and from thence in the generator and causes the
acid in the vessel, C, to flow into the generator through the
leaden siphon tubes, c. Coming in contact with the chalk
in suspension, the acid produces a disengagement of gas
which soon establishes sufficient pressure to stop the flow of
the acid and drive it back into the siphon tube. The play
of the pump continuing, a new suction takes place and
consequently a momentary flow of acid and a new disengagement
of gas. Thus the production of the latter is continuous,
and is regulated by the very action of the pump,

without the operator having to maneuver an acid-cock.
The latter he only has to open when he sets the apparatus in
operation, and to close it when he stops it.

The arrangement of the washer is the same as in the preceding
apparatus, save that a larger cylindrical copper
reservoir, G’, is substituted for the lower flask. The pump
and saturator offer nothing peculiar.

A bent tube, u, which communicates with the generator, D,
on one side, and with a cylindrical tube, V, ending in a glass
vessel on the other, serves as a safety-valve for both the
generator and the acid vessel.

The consumption of chalk is about 2.5 kilogrammes, and
the same of acid, for charging 100 siphons or 150 bottles.
The apparatus shown in the figure is capable of charging
600 siphons or 900 bottles per day.

An Apparatus Completely Mechanical in Operation
(Fig. 11).—This apparatus consists of two very distinct
parts. The saturator, pump, and driving shaft are supported
by a hollow base, in whose interior are placed a copper
washer and the water-inlet controlled by a float-cock.
This part of the apparatus is not shown in the plate. The
generator, partially shown in Fig. 11, is placed on a base of
its own, and is connected by a pipe with the rest of the
apparatus. It consists of two similar generators, D, made
of copper lined with lead, and working alternately, so as to
avoid all stoppages in the manufacture when the materials
are being renewed. The pipe, d, connecting the two parts of
the apparatus forks so as to lead the gas from one or the
other of the generators, whence it passes into the copper
washer within the base, then into the glass indicating
washer, and then to the pump which forces it into the
saturator.

Each of the generators communicates by special pipes,
a, with a single safety vessel, V, that operates the same
as in the preceding apparatus. The agitator, Q, is of
bronze, and is curved as shown in Fig. 11.

The production of this type of apparatus is dependent
upon the number of siphons that can be filled by a siphon
filler working without interruption.—Machines, Outils et
Appareils.

DETECTION AND ESTIMATION OF FUSEL OIL.

Until quite recently we have had no accurate method for
the determination of fusel oil in alcohol or brandy. In 1837
Meurer suggested a solution of one part of silver nitrate in
nine parts of water as a reagent for its detection, stating that
when added to alcohol containing fusel oil, a reddish brown
color is produced, and in case large quantities are present, a
dark brown precipitate is formed. It was soon found, however,
that other substances than amyl alcohol produce brown
colored solutions with silver nitrate; and Bouvier¹ observed
that on adding potassium iodide to alcohol containing fusel
oil, the solution is colored yellow, from the decomposition of
the iodide. Subsequently Böttger² proved that potassium
iodide is not decomposed by pure amyl alcohol, and that the
decomposition is due to the presence of acids contained in
fusel oil. More accurate results are obtained by using a
very dilute solution of potassium permanganate, which is
decomposed by amyl alcohol much more rapidly than by
ethyl alcohol.

Depré³ determines fusel oil by oxidizing a definite quantity
of the alcohol in a closed vessel with potassium bichromate
and sulphuric acid. after removal of excess of the
oxidizing reagents, the organic acids are distilled, and, by
repeated fractional distillation, the acetic acid is separated
as completely as possible. The remaining acids are saturated
with barium hydroxide, and the salts analyzed; a difference
between the percentage of barium found and that of
barium in barium acetate proves the presence of fusel oil,
and the amount of difference gives some idea of its quantity.
Betelli⁴ dilutes 5 c.c. of the alcohol to be tested with 6 to 7
volumes of water, and adds 15 to 20 drops of chloroform and
shakes thoroughly. If fusel oil is present, its odor may be
detected by evaporating the chloroform; or, by treatment
with sulphuric acid and sodium acetate, the ether is obtained,
which can be readily recognized. Jorissen⁵ tests for
fusel oil by adding 10 drops of colorless aniline and 2 to 3 drops
of hydrochloric acid to 10 c.c. of the alcohol. In the presence
of fusel oil a red color is produced within a short time,
which can be detected when not more than 0.1 per cent. is
present. But Foerster⁶ objects to this method because he
finds the color to be due to the presence of furfurol, and that
pure amyl alcohol gives no color with aniline and hydrochloric
acid.

Hager⁷ detects fusel oil as follows: If the spirit contains
more than 60 per cent. of alcohol, it is diluted with an equal
volume of water and some glycerine added, pieces of filter
paper are then saturated with the liquid and exposed to the
After the evaporation of the alcohol, the odor of the
fusel oil can be readily detected. For the quantitative determination
he distills 100 c.c. of the alcohol in a flask of
150 to 200 c.c. capacity connected with a condenser, and so arranged
that the apparatus does not extend more than 20 cm.
above the water bath. This arrangement prevents the fusel oil
from passing over. If the alcohol is stronger than 70 per cent.,
and the height of the distillation apparatus is not more than
17 cm., the residue in the flask may be weighed as fusel oil.
With a weaker alcohol, or an apparatus which projects further
out of the water bath, the residual fusel oil is mixed
with water. It can, however, be separated by adding strong
alcohol and redistilling, or by treating with ether, which dissolves
the amyl alcohol, and distilling, the temperature being
raised finally to 60°.

Marquardt,⁸ like Betelli, extracts the fusel oil from alcohol
by means of chloroform, and by oxidation converts it into
valeric acid. From the quantity of barium valerate found
he calculates the amount of amyl alcohol present in the original
solution; 150 c.c. of the spirit, which has been diluted
so as to contain 12 to 15 per cent. of alcohol, are shaken up
thoroughly with 50 c.c. of chloroform, the aqueous layer
drawn off, and shaken with a fresh portion of chloroform.
This treatment is repeated several times. The extracts are
then united, and washed repeatedly with water. The chloroform,
which is now free from alcohol and contains all the
fusel oil, is treated with a solution of 5 grammes of potassium
bichromate in 30 grammes of water and 2 grammes of
sulphuric acid, and then heated in a closed flask for six hours
on a water bath at 85°. The contents of the flask are then distilled,
the distillate saturated with barium carbonate, and the
chloroform distilled; the residue is evaporated to a small volume,
the excess of barium carbonate filtered off, and the filtrate
evaporated to dryness and weighed. The residue is dissolved

in water, a few drops of nitric acid added, and the
solution divided into two portions. In the first portion the
barium is determined; in the second the barium chloride.
The total per cent. of barium minus that of barium chloride
gives the amount present as barium valerate, from which is
calculated the per cent. of amyl alcohol. By this process
the author has determined one part of fusel oil in ten thousand
of alcohol. To detect very minute quantities of fusel
oil, the chloroform extracts are treated with several drops of
sulphuric acid and enough potassium permanganate to keep
the solution red for twenty-four hours. If allowed to stand
in a test tube, the odor of valeric aldehyde will first be noticed,
then that of amyl valerate, and lastly that of valeric
acid.—Amer. Chem. Journal.

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[2]

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[8]

ON SILICON.

It is known that platinum heated in a forge fire, in contact
with carbon, becomes fusible. Boussingault has shown
that this is due to the formation of a silicide of platinum by
means of the reduction of the silica of the carbon by the
metal. MM. P. Schützenberger and A. Colson have produced
the same phenomenon by heating to white heat a slip
of platinum in the center of a thick layer of lampblack free
from silica.

The increase in weight of the metal and the augmentation
of its fusibility were found to be due, in this case also, to a
combination with silicon. As the silicon could not come
directly from the carbon which surrounded the platinum,
MM. Schützenberger and Colson have endeavored to discover
under what form it could pass from the walls of the
crucible through a layer of lampblack several centimeters in
thickness, in spite of a volatility amounting to almost
nothing under the conditions of the experiment. They describe
the following experiments as serving to throw some light
upon the question:

1. A thin slip of platinum rolled in a spiral is placed in a
small crucible of retort carbon closed by a turned cover of
the same material. This is placed in a second larger crucible
of refractory clay, and the intervening space filled with
lampblack tightly packed. The whole is then heated to
white heat for an hour and a half in a good wind furnace.
After cooling, the platinum is generally found to have been
fused into a button, with a marked increase in weight due to
taking up silicon, which has penetrated in the form of vapor
through the walls of the interior crucible.

2. If, in the preceding experiment, the lampblack be replaced
by a mixture of lampblack and rutile in fine powder,
the slip of platinum remains absolutely intact, and does not
change in weight. Thus the titaniferous packing recommended
by Sainte-Claire Deville for preventing the access of
nitrogen in experiments at high temperatures also prevents
the passage of silicon. A mixture of carbon and finely
divided iron is, on the contrary, ineffectual. These facts
seem to indicate that nitrogen plays a part in the transportation
of the silicon, as this is only prevented by the
same means made use of in order to prevent the passage of
nitrogen.

3. The volatility of free silicon at a high temperature is
too slight to account for the alteration of the platinum at a
distance. This can be shown by placing several decigrammes
of crystallized silicon on the bottom of a small crucible of
retort carbon, covering the silicon with a small flat disk of
retort carbon upon which is placed the slip of platinum.
The crucible, closed by its turned cover, is then enveloped in
a titaniferous packing and kept at a brilliant white heat for
an hour and a half. The metal is found to have only very
slightly increased in weight, and its properties remain unaltered.
This experiment was repeated several times with the
same result. If, however, the crystallized silicon be replaced
by powdered calcined silica, the platinum, placed upon the
carbon disk, fuses and increases in weight, while the silica
loses weight. The theory of these curious phenomena is
very difficult to establish on account of the high temperatures
which are necessary for their manifestation, but it may
be concluded, at present, that nitrogen and probably oxygen
also play some part in the transportation of the silicon across
the intervening space, and that the carbosilicious compounds
recently described by MM. Schützenberger and Colson also
take part in the phenomenon.—Comptes Rendus, xciv.,
1,710.—Amer. Chem. Journal.

STANNOUS NITRATES.

At the Royal Powder Works at Spandau, Prussia, frequent
ignition of the powder at a certain stage of the process
led to an examination of the machinery, when it was
found that where, at certain parts, bronze pieces which were
soldered were in constant contact with the moist powder,
the solder was much corroded and in part entirely destroyed,
and that in the joints had collected a substance which, on
being scraped out with a chisel, exploded with emission of
sparks. It was suspected that the formation of this explosive
material was in some way connected with the corrosion of
the solder, and the subject was referred for investigation to
Rudolph Weber, of the School of Technology, at Berlin.
The main results of his investigation are here given.

The explosive properties of the substance indicated a
probable nitro-compound of one of the solder metals (tin
and lead), and as the lead salts are more stable and better
understood than those of tin, it was resolved to investigate
the latter, in hope of obtaining a similar explosive compound.
Experiments on the action of moist potassium nitrate
on pure tin led to no result, as no explosive body was
formed. Stannous nitrate, Sn(NO₃)₂, formed by the action
of dilute nitric acid on tin, has long been known, but only in
solution, as it is decomposed on evaporating. By adding
freshly precipitated moist brown stannous oxide to cool nitric
acid of sp. gr. 1.20, as long as solution occurred, and
then cooling the solution to -20°, Weber obtained an abundance
of crystals of the composition Sn(NO₃)₂ + 20H₂O.
They resemble crystals of potassium chlorate. They cannot
be kept, as they liquefy at ordinary temperatures. An insoluble
basic salt was obtained by digesting an excess of moist
stannous oxide in solution of stannous nitrate, or by adding
to a solution of stannous nitrate by degrees, with constant
stirring, a quantity of sodium carbonate solution insufficient
for complete precipitation. Thus obtained, the basic salt,
which has the composition Sn₂N₂O₇, is a snow-white
crystalline powder, which is partially decomposed by water, and
slowly oxidized by long exposure to the air, or by heating
to 100°. By rapid heating to a higher temperature, as well
as by percussion and friction, it explodes violently, giving
off a shower of sparks. This compound is also formed when
a fine spray of nitric acid (sp. gr. 1.20) is thrown upon a surface
of tin or solder. It is also formed when tin or solder is
exposed to the action of a solution of copper nitrate, and
thus formed presents the properties already described.

In this, then, we have a probable cause of the explosions
occurring in the powder works; but the explanation of the

formation of the substance is wanting, as potassium nitrate
was shown not to give an explosive substance with tin. A
thin layer of a mixture of sulphur and potassium nitrate
was placed between sheets of tin and copper foil, and
allowed to stand, being kept constantly moist. After a time
the copper was found to have become coated with sulphide,
while the tin was largely converted into the explosive basic
nitrate. The conditions are obviously the same as those
found in the powder machinery, where bronze and tin solder
are constantly in contact with moist gunpowder. The chemical
action is probably this: the sulphur of the powder forms,
with the copper of the bronze, copper sulphide; this is oxidized
to sulphate, which reacts with the niter of the powder,
forming potassium sulphate and copper nitrate; the latter,
as shown above, then forms with the tin of the solder the
explosive basic nitrate, which, being insoluble, gradually
collects in the joints, and finally leads to an explosion.—Journal
für Praktische Chemie.

METALLIC THORIUM.

By L.F. Nilson.

The density of thorium as obtained by reducing the anhydrous
chloride by means of sodium was found by Chydenius,
7.657 to 7.795. The author has obtained metallic
thorium by heating sodium with the double anhydrous
thorium potassium chloride, in presence of sodium chloride
in an iron crucible. After treating the residue with water
there remains a grayish, heavy, sparkling powder, which
under the microscope appears to consist of very small crystals.
Metallic thorium is brittle and almost infusible; the
powder takes a metallic luster under pressure, is permanent
in the air at temperatures up to 120°, takes
fire below a red heat either in air or oxygen, and
burns with a dazzling luster, leaving a residue
of perfectly white thoria. If heated with chlorine,
bromine, iodine, and sulphur, it combines with them with
ignition. It is not attacked by water, cold or hot. Dilute
sulphuric acid occasions the disengagement of hydrogen,
especially if heated, but the metal is acted on very slowly.
Concentrated sulphuric acid with the aid of heat attacks the
metal very slightly, evolving sulphurous anhydride. Nitric
acid, strong or weak, has no sensible action. Fuming hydrochloric
acid and aqua regia attack thorium readily, but
the alkalies are without action. The metal examined by the
author behaves with the reagents in question the same as did
the specimens obtained by Berzelius. The mean specific
gravity of pure thorium is about 11. Hence it would
seem that the metal obtained by Chydenius must have contained
much foreign matter. The specific gravity of pure
thoria is 10.2207 to 10.2198. The equivalent and the density
being known, we may calculate the atomic volume. If we
admit that the metal is equivalent to 4 atoms of hydrogen,
we obtain the value 21.1. This number coincides with the
atomic volumes of zirconium (21.7), cerium (21.1), lanthanum
(22.6), and didymium (21.5). This analogy is certainly not
due to chance; it rather confirms the opinion which I have
put forward in connection with my researches on the selenites,
on certain chloro-platinates and chloro-platinites, etc.,
that the elements of the rare earths form a series of quadrivalent
metals.

[AMERICAN CHEMICAL JOURNAL.]

FRIEDRICH WÖHLER.

No one but a chemist can appreciate the full significance
of the brief message which came to us a month ago without
warning—”Wöhler is dead!” What need be added to it?
No chemist was better known or more honored than Wöhler,
and none ever deserved distinction and honor more than he.
His life was made up of a series of brilliant successes, which
not only compelled the admiration of the world at large, but
directed the thoughts of his fellow workers, and led to results
of the highest importance to science.

It is impossible in a few words to give a correct account
of the work of Wöhler, and to show in what way his life and
work have been of such great value to chemistry. Could he
himself direct the preparation of this notice, the writer knows
that his advice would be, “Keep to the facts.” So far as
any one phrase can characterize the teachings of Wöhler,
that one does it; and though enthusiasm prompts to eulogy,
let us rather recall the plain facts of his life, and let them,
in the main, speak for themselves.¹

He was born in the year 1800 at Eschersheim, a village
near Frankfort-on-the-Main. From his earliest years the
study of nature appears to have been attractive to him. He
took great delight in collecting minerals and in performing
chemical and physical experiments. While still a boy, he
associated with a Dr. Buch, of Frankfort, and was aided by
this gentleman, who did what he could to encourage in the
young student his inclination toward the natural sciences.
The first paper which bears the name of Wöhler dates from
this period, and is upon the presence of selenium in the iron
pyrites from Kraslitz. In 1820 he went to the University of
Marburg to study medicine. While there he did not, however,
neglect the study of chemistry. He was at that time
particularly interested in an investigation on certain cyanogen
compounds. In 1821 he went to Heidelberg, and in 1823
he received the degree of Doctor of Medicine. L. Gmelin
became interested in him, and it was largely due to Gmelin’s
influence that Wöhler gave up his intention of practicing
medicine, and concluded to devote himself entirely to chemistry.
For further instruction in his chosen science, Wöhler
went to Stockholm to receive instruction from Berzelius, in
whose laboratory he continued to work from the fall of 1823
until the middle of the following year. Only a few years
since, in a communication entitled “Jugenderinnerungen
eines Chemikers,” he gave a fascinating account of his journey
to Stockholm and his experiences while working with
Berzelius. On his return to Germany, he was called to teach
chemistry in the recently founded municipal trade school
(Gewerbschule) at Berlin. He accepted the call, and remained
in Berlin until 1832, when he went to Cassel to live.
In a short time he was called upon to take part in the direction
of the higher trade school at Cassel. He continued to
teach and work in Cassel until 1836, when he was appointed
Professor of Chemistry in Göttingen. This office he held at
the time of his death, September 23, 1882.

In 1825 Wöhler became acquainted with Liebig, and an
intimate friendship resulted, which continued until the
death of Liebig, a few years ago. Though they lived far
apart, they met during the vacations at their homes, or traveled
together. Many important investigations were conceived
by them as they talked over the problems of chemistry,
and many papers appeared under both their names, containing
the results of their joint work. Among such papers
may be mentioned: “On Cyanic Acid” (1830); “On Mellithic
Acid” (1830); “On Sulphotartaric Acid” (1831); “On

Oil of Bitter Almonds, Benzoic Acid, and Related Compounds”
(1832); “On the Formation of Oil of Bitter Almonds
from Amygdalin” (1837); and “On Uric Acid”
(1837).

Of the papers included in the above list, the two which
most attract attention are those “On the Oil of Bitter Almonds”
and “On Uric Acid.” In the former it was shown
for the first time that in analogous carbon compounds there
are groups which remain unchanged, though the compounds
containing them may, in other respects, undergo a variety of
changes. This is the conception of radicals or residues as
we use it at the present day. It cannot be denied that this
conception has done very much to simplify the study of
organic compounds. The full value of the discovery was
recognized at once by Berzelius, who, in a letter to the
authors of the paper, proposed that they should call their
radical proin or orthrin (the dawn of day), for the reason
that the assumption of its existence might be likened to the
dawn of a new day in chemistry. The study of this paper
should form a part of the work of every advanced student
of chemistry. It is a model of all that is desirable in a
scientific memoir. The paper on uric acid is remarkable
for the number of interesting transformation products described
in it, and the skill displayed in devising methods
for the isolation and purification of the new compounds.
Comparatively little has been added to our knowledge of
uric acid since the appearance of the paper of Liebig and
Wöhler.

It would lead too far to attempt to give a complete list of
the papers which have appeared under the name of Wöhler
alone. In 1828 he made the remarkable discovery that when
an aqueous solution of ammonium cyanate, CNONH₄, is
evaporated, the salt is completely transformed into urea,
which has the same percentage composition. It would be
difficult to exaggerate the importance of this discovery.
That a substance like urea, which up to that time had only
been met with as a product of processes which take place in
the animal body, should be formed in the laboratory out of
inorganic compounds, appeared to chemists then to be little
less than a miracle. To-day such facts are among the commonest
of chemistry. The many brilliant syntheses of well-known
and valuable organic compounds which have been
made during the past twenty years are results of this discovery
of Wöhler.

In 1823 he published a paper on secretion, in the urine, of
substances which are foreign to the animal organism, but
which are brought into the body. He discovered the transformation
of neutral organic salts into carbonates by the
process of assimilation.

In 1832 he investigated the dimorphism of arsenious acid
and antimony oxide. In 1841 he made the discovery that
dimorphous bodies have different fusing points, according as
they are in the crystallized or amorphous condition.

Among the more remarkable of his investigations in inorganic
chemistry are those on methods for the preparation of
potassium (1823); on tungsten compounds (1824); the preparation
of aluminum (1827); of glucinum and yttrium
(1828). In 1856, working with Ste. Claire Deville, he discovered
crystallized boron.

Analytical methods were improved in many ways, and excellent
new methods were introduced by him. Further, he
did a great deal for the improvement of the processes of applied
chemistry.

With Liebig he was associated in editing the “Annalen
der Chemie and Pharmacie” and the “Handwörterbuch der
Chemie.” He wrote a remarkably useful and popular “Grundriss
der Chemie.” The part relating to inorganic chemistry
appeared first in 1831, and was in use until a few years ago,
when Fittig wrote his “Grundriss” on the same plan, a
work which supplanted its prototype.

The above will serve to give some idea of the great activity
of Wöhler’s life, and the fruitfulness of his labors. While
thus contributing largely by his own work directly to the
growth of chemistry, he did perhaps as much in the capacity
of teacher. Many of the active chemists of the present
day have enjoyed the advantages of Wöhler’s instruction,
and many can trace their success to the impulse gathered in
the laboratory at Göttingen. The hand of the old master
appears in investigations carried on to-day by his pupils.

Wöhler’s was not a speculative mind. He took very little
part in the many important discussions on chemical theories
which engaged the attention of such men as Dumas, Gerhardt,
Berzelius, and Liebig, during the active period of his
life. He preferred to deal with the facts as such; and no
one ever dealt with the facts of chemistry more successfully.
He had a genius for methods which has never been equaled.
The obstacles which had baffled his predecessors were surmounted
by him with ease. He was in this respect a truly
great man.

Personally, Wöhler was modest and retiring. His life was
simple and unostentatious. He had a kindly disposition,
which endeared him to his students, to which fact many
American chemists who were students at Göttingen during
the time of Wöhler’s activity can cordially testify. In short,
it may be said deliberately that Wöhler, as a chemist and as
a man, was a fit model for all of us and for those who will
come after us. Though he has gone, his methods live in
every laboratory. His spirit reigns in many; could it reign
in all, the chemical world would be the better for it.

I.R.

[1]

LOUIS FAVRE, CONSTRUCTOR OF THE ST. GOTHARD TUNNEL.

It is now already a year that the locomotive has been rolling
over the St. Gothard road, crossing at a flash the distance
separating Basle from Milan, and passing rapidly from
the dark and damp defiles of German Switzerland into the
sun lit plains of Lombardy. Our neighbors uproariously
fêted the opening of this great international artery, which
they consider as their personal and exclusive work, as well
from a technical point of view as from that of the economic
result that they had proposed to attain—the creation of a
road which, in the words of Bismarck, “glorifies no other
nation.” As regards the piercing of the Gothard, the initiative
does, in fact, belong by good right to the powerful
“Iron Chancellor,” so we have never dreamed of robbing
Germany of the glory (and it is a true glory) of having created
the second of the great transalpine routes, that open to European
products a new gate to the Oriental world. It seems
to us, however, that in the noisy concert of acclamations
that echoed during the days of the fêtes over the inauguration
of the line, a less modest place might have been made
for those who, with invincible tenacity and rare talent, directed
the technical part of the work, and especially those
15 kilometers of colossal boring—the great St. Gothard Tunnel,
which ranks in the history of great public works side
by side with the piercing of the Frejus, and the marvelous
digging of Suez and Panama.

We recall just now the names of those who, during nearly
ten years, have contributed with entire disinterestedness to
the completion of this colossal work. Over all stands a
figure of very peculiar originality—that of M. Louis Favre,
the general contractor of the great tunnel, whose name will
remain attached to the creation of this work through the
Helvetian Alps, like that of Sommeiller to the great tunnel
of the Frejus, and that of De Lesseps to the artificial straits
that henceforward join the oceans. Having myself had the
honor of occupying the position of general secretary of the
enterprise under consideration, I have been enabled to make
a close acquaintance with the man who was so remarkable
in all respects, and who, after passing his entire life in great
public works, died like a soldier on the field of honor—in
the depths of the tunnel.

LOUIS FAVRE.

THE DOWNFALL OF THE TITANS, CONQUERED BY THE GENIUS OF MAN. (Monument at Turin to Commemorate the Tunneling of the Alps.)

I saw Favre, for the first time, in Geneva, in 1872, a few
days after he had assumed the responsibility of undertaking
the great work. He had been living since the war on his
magnificent Plongeon estate, on the right bank of the lake.
There was no need of dancing attendance in order to reach
the contractor of the greatest work that has been accomplished
up to the present time, for M. Favre was easy of access.
We had scarcely passed five minutes together than we
we were conversing as we often did later after an acquaintance
of six years. After making known to him the object
of my visit, the desire of being numbered among the personnel
of his enterprise, the conversation quickly took that turn

of mirthfulness that was at the bottom of Favre’s character.
“This is the first time,” said he to me, laughing, “that
I ever worked with Germans, and I had not yet struck the
first blow of the pick on the Gothard when they began to
quibble about our contract of the 8th of last August. Ah!
that agreement of August 8th! How I had to change and re-change
it, later on. If this thing continues, we shall have
a pretty quarrel, considering that I do not understand a
word of the multiple interpretations of their charabia. I
ought to have mistrusted this. But you see I have remained
inactive during the whole of this unfortunate war. I was
not made for promenading in the paths of a garden, and I
should have died of chagrin if such inaction had had to be
prolonged. When one lives, as I have, for thirty years around
lumber yards, it is difficult to accustom one’s self to the
sedentary and secluded life that I have led here for nearly
two years.”

As he said, with just pride, Louis Favre had, indeed, before
becoming the first contractor of public works in the
world, lived for a long time in lumber yards. The years
that so many other better instructed but less learned persons,
who were afterward to gladly accept his authority,
had given up to their studies, Favre had passed in the humble
shop of his father, a carpenter at Chêne, a small village
at a half league from Geneva. It soon becoming somewhat
irksome for him in the village, he left the paternal workbench
to start on what is called the “tour of France.” He
was then eighteen years of age. Three years afterward, he
was undertaking small works. It was not long ere he was
remarked by the engineers conducting the latter, and he was
soon called to give his advice on all difficult questions. Between
times, Favre had courageously studied the principal
bases of such sciences as were to be useful to him. In the
evening, he made up at the public school what was lacking
in his early instruction; not that he hoped to make a complete
study for an engineer, but only to learn the indispensable.
He was, before all things, a practical man, who made
up for the enforced insufficiency of his technical knowledge
by a coup d’œil of surprising accuracy. Here it may be said
to me that the piercing of the great St. Gothard Tunnel was
accompanied by considerable loss. That is true, but it must
be recalled also that this colossal work was accomplished
amid the most insurmountable difficulties which ever presented
themselves. In spite of this, the cost of the tunnel
per running foot was also a third less than that of the great
Mont Cenis Tunnel.

When Favre undertook the St. Gothard, he already reckoned
to his credit numerous victories in the domain of public
works, especially in the construction of subterranean
ones. The majority of tunnels of any length which, since
the beginning of the establishment of railways, have been
considered as works of some proportions (the Blaisy Tunnel,
for instance), were executed by him, in addition to other
open air works. So Favre reached the St. Gothard full of
hope. The battle with the colossus did not displease him,
and his courage and his confidence in the success of the
work seemed to increase in measure as the circumstances
surrounding the boring became more difficult. In the presence
of the terrible inundation of the gallery of Airolo and
the falling of aquiferous rocks, creating in the subterranean
work so desperate a situation that a large number of very experienced
engineers almost advised the abandonment of the
works, Favre remained impassive. Amid the general apprehension,
which, it may be readily comprehended, was felt in

such a situation he made his confident and cheerful voice
heard, reviving the ardor of all, and speaking disdainfully
of “that insignificant Gothard, which would come out all
right.” The personnel of the enterprise were not the only
ones, however, who were uneasy over the constantly occurring
difficulties in the way of the work, for the company
itself and the Swiss Federal Council made known to Favre
their fears that the execution of the work would be delayed.
He, however, calmed their fears, and exposed his projects
to them, and the seances always ended by a vote of confidence
in the future of the undertaking. Favre certainly did
not dissimulate the difficulties that he should have to conquer,
but he execrated those who were timorous and always
tried to put confidence into those who surrounded him.
But, singular phenomenon, he ended by deceiving himself
and, at certain times, it would not have been easy to prove
to him that the St. Gothard was not the most easy undertaking
in the world. Those who have lived around him know
the jokes that he sometimes made at the expense of poor
Gothard, which paid him back with interest, however, and
did not allow itself to be pierced so easy after all.

Such confidence as existed in the first years, however, was
not to exist for ever. The tunnel advanced, the heading
deepened, but at the price of what troubles, and especially
of how many expenses! Day by day one could soon count
the probable deficit in the affair and the silent partners began
to get a glimpse of the loss of the eight millions of securities
that had had to be deposited with the Swiss Federal
Council. For Favre personally the failure of the enterprise
would have been ruin for his fortune was not so large as
has been stated. To fears which Favre possessed more on
account of the associates that he had engaged in the enterprise
than for himself, came to join themselves those troubles
with the Germans that he had spoken to me about on
the first day. The St. Gothard Company, whose troubles
are so celebrated, and whose inactivity lasted until the reconstruction
of the affair, was seemingly undertaking to
make Favre, who was directing the only work then in activity,
bear all the insults that it had itself had to endure. And
yet, amid these multiple cares, the contractor of the tunnel
did not allow himself to become disheartened. Constantly
at the breach he lived at his works, going from the gigantic
adit of Goschenen to the inundated one of Anolo, constantly
on the mountain, having no heed of the icy and perilous
crossing, and passing days in the torrential rain that was
flooding the tunnel. Who of us does not picture him in
mind as he reached the inn at night, with his high boots still
soaking wet, and his gray beard full of icicles to take his
accustomed seat at the table, and, between courses, to tell
some story full of mirth, some joke from the other works
whence he had come, which made us laugh immoderately,
and brought a smile to the faces of the German engineers.

It is a singular coincidence that this confidence in his own
work, despite all the struggles borne, was shared likewise by
another man than Favre—by Germano Sommeiller, the creator
of the Mont Cenis Tunnel. When the work of the first
piercing of the Alps was yet in the period of attacks and
incredulity, Sommeiller wrote his brother the following letter:
“Always keep me posted my dear Leander, as to what
the laughers are saying and remember the proverb that
‘he will laugh well who laughs last!’ The majority of the
people, even engineers, are rubbing their hands in expectation
of the colossal fiasco that awaits us, and it is for that
that the envious keep somewhat silent. I will predict to
you that as soon as success is assured everybody will mount
to the house tops and say ‘I told you so! It was an idea of
my own!’ What great geniuses are going to spring from
the earth! I am in haste, so adieu, courage, energy, silence
and especially cheerfulness! And especially cheerfulness!”
Perhaps this cheerfulness of strong minds is the invincible
weapon of those who, like Sommeiller and Favre, fight
against apathy or the bad faith of their adversaries! Like
Favre however Sommeiller had not the pleasure of being
present at the consecration of his glory, for at the Mont Cenis
banquet as at the St. Gothard the place reserved for the
creator of the great work was empty.

As disastrous as was the enterprise from a financial point
of view what a triumph for Favre would have been the day
on which he traversed from one end to the other that 15 kilometers
of tunnel that he had walked over step by step
since the first blow of the pick had struck the rock of the
St. Gothard! But such a satisfaction was not to be reserved
for him. Suddenly, on the 19th of July, 1879, less than
seven years after the beginning of the work, and six months
before the meeting of the adits, in the course of one of his
visits to the tunnel Favre was carried off by the rupture of
a blood vessel. A year before that epoch, I had left the enterprise,
Favre having confided to me the general supervision
over the manufacture of dynamite that he had undertaken at
Varallo Pombia for the needs of his tunnel, but my friend
M. Stockalper, engineer in chief of the Goschenen section,
who accompanied Favre on his fatal subterranean excursion,
has many a time recounted to me the sad details of his sudden
death.

For months before it must be said Favre had been growing
old. The man of broad shoulders and with head covered
with thick hair in which here and there a few silver threads
showed themselves, and who was as straight as at the age of
twenty years, had begun to stoop, his hair had whitened
and his face had assumed an expression of sadness that it
was difficult for him to conceal. As powerful as it was
this character had been subjugated. The transformation
had not escaped me. Often during the days that we passed
together he complained of a dizziness that became more and
more frequent. We all saw him rapidly growing old. On
the 19th of July, 1879, he had entered the tunnel with one
of his friends, a French engineer who had come to visit the
work, accompanied by M. Stockalper. Up to the end of the
adit he had complained of nothing, but, according to his
habit, went along examining the timbers, stopping at different
points to give instructions, and making now and then a
sally at his friend, who was unused to the smell of dynamite.
In returning he began to complain of internal pains. “My
dear Stockalper,” said he, “take my lamp, I will join you.”
At the end of ten minutes not seeing him return, M. Stockalper
exclaimed, “Well! M. Favre, are you coming?” No
answer. The visitor and engineer retraced their steps, and
when they reached Favre he was leaning against the rocks
with his head resting upon his breast. His heart had already
ceased to beat. A train loaded with excavated rock
was passing and on this was laid the already stiff body of
him who had struggled up to his last breath to execute a
work all science and labor. A glorious end, if ever there
was one!

Favre died in the full plenitude of his forces at less than
fifty four years of age, and I can say, without fear of contradiction,
that he was universally and sincerely regretted
by all those who had worked at his side. Still at the present
time when a few of us old colleagues of Goschenen,

Airolo or Altorf meet, it is not without emotion that we
recall the old days, the joyful reunions at which he cheered
the whole table with his broad and genial laugh.—Maxime
Helene, in La Nature.

THE NEW HARBOR OF VERA CRUZ.

Besides the enormous engineering work of rendering
navigable one of the mouths of the Mississippi Delta, and the
continuous labor of developing the more original and still
bolder project for an Isthmian ship railway, Mr. James B.
Eads has been engaged in the design of new and extensive
harbor works at Vera Cruz, which, when completed, will
secure for that city a commodious and secure port. The
accompanying plan shows the natural features of the locality,
as well as the new works. The harbor is formed by the
coast line from the Punta de la Caleta to the Punta de
Hornos, and by La Gallega reef. From the first named
point a coral reef, nearly dry at low water, extends out about
300 yards into the gulf, and a similar one of about the same
length runs out from the Punta de Hornos. Between these
is a bay 2,000 meters wide, and at its northwest end lies the
city of Vera Cruz. The bay is partly inclosed by an island
or reef—La Gallega—which, on the harbor front, has a
length of 1,200 meters. Beyond this, and to the southeast,
is another small island—the Lavendera reef. Between the
end of this reef and that projecting from the Punta de Hornos
is 320 meters wide. As will be seen from the plan the
natural harbor is exposed to the gale from the north and
northwest, while the formation affords general protection
from the northeast and southeast thanks to five large
coral reefs. Not unfrequently, however, heavy seas sweep
through the wide channels between these small islands interfering
seriously with vessels lying alongside the present
limited wharfage. Northeast, La Gallega and Gallaguilla
reefs run northward from the harbor for 3,300 meters and
these with the main coast line, form a bay exposed to the
full fury of the winds from the north, and when northern
winds prevail rough water is driven through the passage
between La Gallega and Caleta reefs with great violence,
and sets up a rapid and dangerous current into the harbor.

NEW HARBOR AT VERA CRUZ.

From the foregoing it will be seen that, while presenting
some advantages, the natural harbor of Vera Cruz possesses
many drawbacks and dangers which the design of Mr. Eads
will completely remove. The leading features of the works
about to be carried out are indicated on the plan. They
comprise

1. The construction of a sea wall between La Gallega and
the Lavendera reefs, with an extension over the latter.

2. The construction of a sea wall from Punta de la Caleta
to La Gallega. This part of the work will be begun after
the completion of the first wall to a height of at least 3 ft.
above low water.

3. A dike connecting the northern ends of the first two
dikes with each other, and stretching across the southern
part of La Gallega, to prevent the seas which sometimes
break over this reef from entering the harbor. The wall
between La Gallega and Lavendera will not only cut off
the rough water during northerly gales, but will also effectually
prevent the deposition of sand in the harbor, because

the through passage to the northwest will be stopped.
Passages closed by sluice gates will be formed through this
wall at about low water level, so that at any time the harbor
may be flushed out and stagnation prevented.

4. After the construction of the inclosing walls the harbor
will be dredged out and cleared of coral to a depth of 25ft.
below low water.

5. Following these works of primary importance comes
the construction of a wooden roadway from the Hornos reef
to the northwestern dike. This roadway will form the
south front of the harbor, and the excavated material will
be deposited on the space between the roadway and the
existing bottom, so as ultimately to make it a permanent
work with a masonry retaining wall fronting the harbor.
The land between the roadway and the city would also be
reclaimed to the extent of more than 740,000 square yards.

6. The construction of wooden piers at right angles to the
roadway, which would be extended to run around the harbor
as trade required it, for ships to be alongside for loading
and unloading. The construction of these short piers would
be similar to those used in New York and other United
States ports, and they might afterward be replaced by
masonry if the increase in trade justified so large an expenditure.

7. The erection of a lighthouse, at or near the eastern
end of the Lavendera sea wall of a second on the eastern
side of La Gallaguilla reef, and of another on the west side
of La Blanquilla reef. These houses will be furnished with
distinctive signals to enable steamers running in before
another to run with safety between La Gallaguilla and La
Blanquilla as soon as the Lavendera light is seen between
the other two.

The width of deep water at the entrance between the Lavendera
and Hornos reefs will be 1,000 ft. The estimated
cost of these extensive works is ten millions of dollars, a
large sum for the Mexican Republic to expend in harbor
improvements at one port but it will doubtless be found a
profitable investment as it will tend greatly to promote
trade, and so increase indefinitely the commerce of the port.

Mr. Eads’ plan having been approved by the Mexican
Government the work was formally commenced on the
14th of last August. Plans were also furnished by him at
the request of the Government, for deepening the mouth of
the Panuco River upon which is located the city of Tampico,
the Gulf terminus of the Mexican central railway system.—Engineering.

COST OF POWER TO MAKE FLOUR.

The following estimate of the cost of the power required to
manufacture a barrel of flour is taken from the Miller. The
calculation would hardly hold good in this country owing
to difference in cost of fuel attendance etc., but is nevertheless
of interest.

“The cost of a steam motor per 20 stone (280 lb.) sack of
flour depends entirely on local circumstances. It depends
first, on the amount of power expended in the production
of a sack of flour, that is on its mode of manufacture, and
it depends, secondly, on the cost of the necessary amount of
power, that is, on the cost of fuel burned per horse power

The average consumption of coal of first class steam engines
may be taken at 2 lb. per hour per indicated horse power.

“Supposing a mill with six pairs of stones, two pairs of
porcelain roller mills, and the necessary dressing, purifying,
and wheat cleaning machinery to require a steam motor of
100 indicated horse power to drive it, then the average
consumption of fuel in this mill would be 200 lb. of coal per
hour. Such a mill working day and night will turn out
about 400 sacks of flour per week of, say, 130 hours, so that
200 × 13 = 26,000 lb. of coal would be required to manufacture
400 sacks of flour. The cost of this quantity of coal may
be taken at, say, £12 (about $58.32), and for cost of attending
engine and boiler, cost of oil, etc., another £3 (about
$14.58) per week may be added; so that, in this case, the
manufacture of 400 sacks of flour would cause an expenditure
of £15 ($72.90) for the steam motor. Therefore the cost
of the steam motor per 20-stone sack of flour may be taken
at 9d. (about 18 cents) per sack, if an improved low grinding
system is used.

“In this case it is supposed that about 55 per cent. of flour
is obtained in the first run, leaving about 30 per cent. of
middlings and about 12 per cent. of bran, which is finished in
a bran duster. The middlings are purified, ground over one
pair of middling stones, then dressed through a centrifugal
and the tailings of the latter are passed over one of the porcelain
roller mills, whereas the other porcelain roller mill treats
the second quality of middlings coming from the purifier.
The products from the two porcelain roller mills are dressed
through a second centrifugal, and the whole flour is mixed
into one straight grade. Four pairs of stones are supposed
to work on wheat, one on middlings, and one pair is sharpening.
The first run is supposed to be dressed through two
long silk reels. Of course, not every steam motor has so
low a consumption of coal as two pounds per hour per horse
power; it often amounts to three, four, and five pounds per
hour. In that case, of course, the cost of steam power per
sack is much greater than 9d. per sack. A greater number
of breaks does not necessarily increase the cost of steam
power per sack of flour. Although more machines may be
employed, each of them may require less horse power;
so that the total amount of power required for manufacturing
an equal amount of flour may not be greater in the case
of gradual reduction.

“As, however, the cost of maintenance may be slightly
greater in the latter case, on account of a greater number of
more elaborate machines, the cost of manufacturing a sack
of flour may be a little greater when gradual reduction is
employed, taking into account the total expenses of the mill
and interest on the capital employed.

“Water motors are generally a much cheaper source of
energy than steam motors, but they are not so reliable and
constant as the latter. The very irregular supply of water
sometimes causes stoppages of the mill, and often a reserve
steam engine has to be provided in order to assist the water
motor when the quantity of water decreases during the
summer months. Wind motors were formerly extensively
used for milling purposes, but they are now gradually disappearing.
They are too irregular and unreliable, although
they utilize a very cheap motive power. It is not advantageous
to expend a large amount of capital for a mill which
often is unable to work at the very time when there are
favorable opportunities for doing profitable business. Animal
motors are too dear. They are only suitable for driving
very small mills in out of the way localities.”

DRIVING GEAR MECHANISM FOR LIFT HAMMERS.

A very interesting system of driving gear for lift hammers
was applied in an apparatus exhibited at Frankfort in 1881
by Mr. Meier of Herzen. The arrangement of the mechanism
is shown in Figs. 1 and 2. In the upper part of the hammer-frame
there is a shaft which is possessed of a continuous
rotary motion, and, with it, there is connected by a
friction coupling a drum that receives the belt from which
is suspended the hammer. In the apparatus exhibited, the
mechanism is so arranged that the hammer must always follow
the motion of the controlling lever in the same direction;
but a system may likewise be adopted such that the
hammer shall continue to operate automatically, when
and so long as a lever prepared for such purpose is lowered.

ab is the shaft having a continuous rotary motion, and
upon which are fixed the pulley, c, the fly-wheel, d, and
the friction-disk, e. Upon one of the extremities of the
driving shaft is fixed an elongated sleeve, formed of the
drum, g, and of the screw, f, carried by the nut, h. This
latter is supported in the frame in such a way that it cannot
turn, but can move easily in the direction of the axis. Such
motion may be produced by the spring, i, and its extent is
such that the drum, g, is brought in contact with the friction-disk, e.

The hand-lever, k, rod, l, and bent lever, m, serve to bring
about a motion in the opposite direction, and which disengages
the drum, g, from the disk, e, and lets the hammer
fall; the drum being then able to turn freely. If the lever, k,
be afterward raised again, the spring, i, will act anew and
couple the drum with the driving-shaft, so that the hammer
will be lifted. In this rotary motion the screw, f, turns or
re-enters into its nut, which it displaces toward the left,
since it cannot itself move in that direction until the rectilinear

motion be wiped out, and the power of the spring be thus
overcome. At the same moment, the screw should naturally
also make this rectilinear movement forward, that is to
say, the coupling would be disengaged, if, at the least lateral
motion toward the right, the spring, i, did not push the
system toward the left. There is thus produced a state of
equilibrium such that there is just enough friction between
the disk, e, and the drum, g, to keep the hammer at
rest and suspended. Through the action of an external force
which lowers the lever, K, the hammer at once falls, and the
screw issues anew from its nut and brings the parts into their
former positions.

MEIER’S DRIVING GEAR MECHANISM FOR LIFT HAMMERS.

DE JUNKER & RUH’S MACHINE FOR CUTTING ANNULAR WHEELS.

The machine shown in Figs. 1, 2, and 3 has been devised
by Messrs. Junker & Ruh, of Carlsruhe, for cutting internally-toothed
gear-wheels. The progress of the work is such that
the wheel is pushed toward the tool by a piece, n, provided
with a curve guide, and that the tool is raised and separated
from the wheel after a tooth has been cut, in order to
allow the wheel to revolve one division further.

The tool is placed in a support, b, which is fixed to the
upright, d, in such away that it may revolve; and this support
is connected to the frame, a, of the machine. A strong
flat spring, f, constantly presses the tool-carrier, b, toward
the upright, d, as much as the screw, g, will permit; and
this pressure and the tension of the belt draw the tool downward.
The screws, g, determine the depth of the cut, and
compensate for the differences in the diameter of the tool.

MACHINE FOR CUTTING ANNULAR WHEELS.

The wheels to be cut are set by pressure into a wrought iron
ring, with which they are placed in a sleeve or support, h.
The connection between the two is assured by means of a
nut, c. The axle of the support, h, is held in the upright of
the carriage, k, which receives from a piece, l, placed on
the driving-shaft, n, a slow forward motion toward the tool,
and a rapid motion backward. The trajectory curve or
groove of special form of the piece, l, in which moves the conducting
roller, o, of the carriage, is not closed everywhere
on the two sides, in that the guides that limit it extend only

on the part strictly necessary. This arrangement permits
of the roller being made to leave the trajectory in order that
the carriage may be drawn back to a sufficient distance from
the tool when the wheel is finished, so as to replace the latter
by another.

One hollow is cut during each forward travel of the carriage;
and, when such travel is finished, a cam-disk, p,
placed on the shaft, n, lifts the tool-carrier, b, and thus
draws the cutting-tool out of the hollow cut by it, so that the
carriage cam can then move back without restraint. In the
interim, the sleeve, h, which supports the wheel, revolves one
tooth through the following arrangement: On the axis, e, of
this sleeve there are two ratchet-wheels, r and s, the number
of whose teeth is equal to that of the teeth to be cut in the
wheel. The wheel, r, produces the rotation of the sleeve, h,
and the wheel, s, keeps the shaft stationary during the operation.
The two wheels are set in motion by a lever, t, or by
its click, this lever being raised at the desired moment on the
free extremity of the driving shaft, n, by a wedge, u. The
short arm of the lever, t, engages, through its point of appropriate
shape, with the teeth of the wheel, s, so as to keep
this latter stationary while the tool is cutting out the interspace
between the teeth. When the lever, t, is raised, this
point is at first disengaged from the wheel, s; and the raising
of the lever being prolonged, the button, i, places itself
against the upper curve of the slot in the lever, q, and
raises that likewise. q is connected with the lever, v, which
revolves about the axis, e, and v carries the click, w, so that
when the lever, v, is raised, the wheel, r, turns forward by
one tooth. When the lever, t, is lowered, as the wedge, u,
turns more, its click holds the wheel, s, stationary. This
series of operations is repeated until the last interspace between
the teeth has been cut, when the machine stops automatically
as follows: A cam of the disk, A, which receives
from the shaft, n, through cone-wheels, a motion corresponding
to that of the wheels, r and s, abuts against the two-armed
lever, z, and this latter then disengages the rod, y, so
that the weight, G, can move the fork, B, in such a way that
the belt shall pass from the fast to the loose pulley.

Motion is communicated to the machine as a whole by the
shaft, C, which is provided with a fast and loose pulley. As
shown in the engraving, the pulley, D, moves the tool, and
the pulley, E, causes the revolution of the shaft, n, through
a helicoidal gearing, F.

The construction of the tool carrier is represented in detail
in Fig. 3. The cutting tool, F, rests on a sleeve forming
part of the pulley, r₁, against which it is pressed by a
nut, while its position is fixed by a key. The axle, s₁, of the
tool is held in two boxes, in which it is fixed by screws. In
order that the tool may be placed exactly in the axis of the
wheel to be toothed, and that also the play produced by
lateral wear of the pulley, r₁, may be compensated for, two
screws, r₂, are arranged on the sides. All rotation of the
shaft, s₁, is prevented by a screw, o, which traverses the cast
iron stirrup, C, and the steel axle box.

RECENT HYDRAULIC EXPERIMENTS.

At a late meeting of the Institution of Civil Engineers, the
paper read was on “Recent Hydraulic Experiments,” by
Major Allan Cunningham, R.E.

This paper was mainly a general account of some extensive
experiments on the flow of water in the Ganges Canal,
lasting over four years—1874-79. Their principal object
was to find a good mode of discharge measurements for large
canals, and to test existing formulæ. There are about 50,000
velocity, and 600 surface-slope measurements, besides many
special experiments. The Ganges Canal, from its great size,
from the variety of its branches abounding in long straight
reaches, and from the power of control over the water in it,
was eminently suited for such experiments. An important
feature was the great range of conditions, and, therefore, also
of results obtained. Thus the chief work was done at thirteen
sites in brickwork and in earth, some being rectangular
and others trapezoidal, and varying from 193 ft. to 13 ft. in
breadth, and from 11 ft. to 7 in. in depth, with surface-slopes
from 480 to 24 per million, velocities from 7.7 ft. to 0.6 ft.
per second, and discharges from 7,364 to 114 cubic feet per
second. For all systematic velocity measurements, floats
were exclusively used, viz., surface floats, double floats, and
loaded rods. Their advantages and disadvantages had been
fully discussed in the detailed treatise “Roorkee Hydraulic
Experiments”—1881. They measured only “forward velocity,”
the practically useful part of the actual velocity. The
motion of water, even when tranquil to the eye, was found
to be technically “unsteady;” it was inferred that there is
no definite velocity at any point, and that the velocity varies
everywhere largely, both in direction and in magnitude.
The average of, say, fifty forward velocity measurements at
any one point was pretty constant, so that there must be probably
average steady motion. Hence average forward velocity
measurements would be the only ones of much practical use.
To obtain these would be tedious and costly, and special
arrangements would be required to obviate the effects of a
change in the state of water, which often occurred in a long
experiment, as when velocities at many points were wanted.

As to surface-slope its measurement—from nearly 600
trials—was found to be such a delicate operation that the
result would be of doubtful utility. This would affect the application
of all formulas into which it entered. The water surface
was ascertained, on the average of its oscillations, to be
sensibly level across, not convex, as supposed by some writers.

There were 565 sets of vertical velocity measurements combined
into forty-six series. The forty-six average curves
were all very flat and convex down stream—except near an
irregular bank—and were approximately parabolas with
horizontal axes; the data determined the parameters only
very roughly; the maximum velocity line was usually below
the service, and sank in a rectangular channel, from the
center outward down to about mid-depth near the banks.
Its depression seemed not to depend on the depth, slope,
velocity, or wind; probably the air itself, being a continuous
source of surface retardation, would permanently depress
the maximum velocity, while wind failed to effect this, owing
to its short duration. On any vertical the mid-depth
velocity was greater than the mean, and the bed velocity
was the least. The details showed that the mid-depth
velocity was nearly as variable from instant to instant as
any other, instead of being nearly constant, as suggested by
the Mississippi experimenters.

The measurement of the mean velocity past a vertical was
thought to be of fundamental importance. Loaded rods
seemed by far the best for both accuracy and convenience in
depths under 15 ft. They should be immersed only 0.94 of
the full depth. The chief objection to their use, that—from
not dipping into the slack water near the bed—they moved
too quickly, was thus for the first time removed. A double
float with two similar sub-floats at depths of 0.211 and 0.789 of
the full depth would also give this mean with more accuracy
and convenience than any instrument of its class; this instrument
is new. Measurement of the velocity at five eighths
depth would also afford a fair approximation.

One hundred and fourteen average transverse velocity
curves were prepared from 714 separate curves. These
average curves were all very flat, and were convex down
stream—over a level or concave bed—and nearly symmetric
in a symmetric section. The velocity was greatest near the
center, or deepest channel, decreased very slowly at first toward
both banks, more rapidly with approach to the banks
or with shallowing of the depth, very rapidly close to the
banks, and was very small at the edges, possibly zero. The
figure of the curve was found to be determined by the figure
of the bed, a convexity in the bed producing a concavity
in the curve and vice versa, and more markedly in shallow
than in deep water. Curves on the same transversal,
at the same site, and with similar conditions, but differing
in general velocity, were nearly parallel projections. At
the edges there was a strong transverse surface flow from the
edge toward mid-channel, decreasing rapidly with distance
from the edge. The discussion showed that it was almost
hopeless to seek the geometric figure of the curves from
mere experiment.

Five hundred and eighty-one cubic discharges were measured
under very varied conditions. The process adopted
contained three steps: (1) Sounding along about fifteen float
courses, scattered across the site in eight cross sections; time,
say four hours. (2) Measurement of the mean velocities
through the full depths in those float courses, each thrice repeated;
time, say four hours. (3) Computation, say two
hours. This process was direct and wholly experimental;
each step was done in a time which gave some chance of a
constant state of water. From an extended comparison of
all results under similar conditions, it appeared that the
above process yielded, under favorable circumstances, results
not likely to differ more than 5 per cent. The sequel showed
that in a channel with variable regimen, a discharge table
for a given site must be of at least double entry, as dependent
on the local gauge-reading, and on the velocity or surface-slope.

Special attention was paid to rapid approximations to
mean sectional velocity. The mean velocity past the central
vertical, the central surface velocity, and Chézy’s quasi-velocity—i.e.,

100 × √( R × S )

where R=the hydraulic mean depth,
and S=surface slope—were tried in detail; thus 100, 76,
and 83 average values thereof respectively were taken from
581, 313, and 363 detail values. The ratios of these three
velocities to the mean velocity were taken out, and compared
in detail with Bazin’s and Cutter’s coefficients. Other
formulæ were contrasted also in slight detail. Kutter’s alone
seemed to be of general applicability; when the surface
slope measurement is good, and the rugosity coefficient
known for the site—both doubtful matters—it would probably
give results within 7½ per cent. of error. Improvement
in formulæ could at present be obtained only by increased
complexity, and the tentative research would be excessively
laborious. Now the first two ratios varied far less
than the third; thus their use would probably involve less
error than the third, or approximation would be more likely
from direct velocity measurement than from any use of
surface slope. The connection between velocities was probably
a closer one than between velocity and slope; the former
being perhaps only a geometric, and the latter a physical
one. The mean velocity past the central vertical was recommended
for use, as not being affected by wind; the reduction
coefficient could at present only be found by special experiment
for each site. Three current meters were tried for
some time with a special lift, contrived to grip the meter
firmly parallel to the current axis, so as to register only forward
velocity, and with a nearly rigid gearing wire. No
useful general results were obtained. Ninety specimens of
silt were collected, but no connection could be traced between
silt and velocity; it seemed that the silt at any point
varied greatly from instant to instant, and that the quantity
depended not on the mean velocity, but probably on the silt
in the supply water. Forty measurements of the evaporation
from the canal surface were made in a floating pan,
during twenty five months. The average daily evaporation
was only about 1/10 in. The smallness of this result seemed
to be due to the coldness of the water—only 63 deg. in May,
with 165 deg. in the sun and 105 deg. in shade. Lastly, it
must suffice to say that great care was taken to insure accuracy
in both fieldwork and computation.

THE GERM.

By Arthur Atkins.

There seems to have sprung up within a few mouths
a tendency to revive the discussion on that hackneyed question,
“Shall the germ be retained in the flour?” This
question has been more than once answered in the negative
by both scientific and practical men, but recently certain
prominent persons have come to the conclusion that
every one has been wrong on this point, and the miller should
by all means retain the germ. Now the nutritive value of
the germ cannot be disputed, but there are two circumstances
which condemn it us an ingredient of flour. The
first is that the albuminoids which it contains are largely
soluble, and this means that good light bread from germy flour
is impossible. I have not time to go into a detailed explanation
of the chemical reasons for this, but they may be found in

a series of articles which appeared in The Milling World about
a year ago. In the next place, the oil contained in the germ
not only discolors the flour, but seriously interferes with its
keeping qualities. Now color is only a matter of taste, and
if that were the only objection to the germ, it might be admitted,
but we certainly do not want anything in our flour
to interfere with making light, sweet bread, and will render
it more liable to spoil. If our scientists can discover some
method of obviating these objections, it will then be time
enough to talk about retaining the germ. Meanwhile millers
know that germy flour is low priced flour, and they are not
very likely to reduce their profits by retaining the germ.—Milling World.

WHEAT TESTS.

There was considerable complaint last season, on the
part of wheat raisers in sections tributary to Minneapolis,
on account of the rigid standard of grading adopted by the
millers of that city. It was asserted that the differentiation of
prices between the grades was unjustly great and out of proportion
to the actual difference of value. In order to ascertain
whether this was the case or not, the Farmers’ Association
of Blue Earth County, Minn., decided to have samples of each
grade analyzed by a competent chemist in order to determine
their relative value. Accordingly specimens were secured,
certified to by the agent of the Millers’ Association of Minneapolis,
and sent to the University of Minnesota for analysis.
The analysis was conducted by Prof. Wm. A. Noyes, Ph.D.,
an experienced chemist, who has recently reported as follows:

“The analyses of wheat given below were undertaken for
the purpose of determining whether the millers’ grades of
wheat correspond to an actual difference in the chemical
character of the wheat. For this purpose samples of wheat
were secured, which were inspected and certified to by M.
W. Trexa on April 13th of this year. The inspection cards
contained no statement except the grade of the wheat and
the weight per bushel, but the samples were all of Fife, for
the purpose of a better comparison. The analyses of the
wheat were made during October in this laboratory. In
each case the wheat was carefully separated from any foreign
substances before analysis. The results of analysis
were as follows:

“The analyses require but little comment. The only substances
in which there is evident connection between the
results of analysis and the grades of wheat are the cellulose,
ash, and phosphorus. As regards the last substance, grades
two and three seem to have the greatest food value. But
it seems quite probable from the results that greater difference
would be found between different varieties of wheat
of the same kind than is shown here between different
grades of the same variety of wheat. However, it does not
necessarily follow from this that the different grades of wheat
are of nearly equal value to the miller for the purpose of making
flour. That is a question which can be best answered by determining
accurately the amount and character of the flour
which can be made from each grade of wheat. If possible,
the investigation will be continued in that direction.”

As Prof. Noyes justly remarks, the value of the different
grades of wheat can best be determined by a comparison of
the results of reducing them to flour, but an intelligent
study of the table given above would of itself be sufficient
to indicate the justness of the grading. In the first place,
even were the percentages of the different components exactly
the same in each grade, still the difference in weight
would of itself be sufficient to justify a marked difference in
price. This requires no proof, for, other things being equal,
fifty-nine pounds is worth more than fifty-five pounds.
Again, the figures show that No. 3 contained nearly four
times as much foreign matter as No. 1. Millers certainly
should not be expected to pay for foreign seeds or other substances
valueless for their purpose, at the price of wheat.
Finally, if the analysis proves anything, it proves that the
lower grades contain a decidedly larger percentage of components
which it is generally agreed, whether directly or the
reverse, ought not to be incorporated with the flour, and
are, therefore, of comparatively little value to the miller.
This is shown by the relative amounts of cellulose, ash, and
phosphorus present. Cellulose, as every one knows, is the
woody, indigestible substance which is found in the bran,
and the greater the amount of cellulose, the heavier will be
the bran in proportion to the flour producing elements.
According to the figures presented, No. 3 contained nearly
one-quarter more cellulose than No. 1, while the amount in
No. 2 was slightly less than in No. 3. The ash, too, which
represents the mineral constituents of the wheat, is directly
dependent upon the quantity of bran. Here, too, the lowest
grade is shown to yield about one-quarter more than the
highest. The larger percentage of phosphorus in the lower
grades is suggested by the analyst to indicate their greater
food value in this respect. So it would, were we in the habit
of boiling our wheat and heating it whole, or of using
“whole wheat meal.” But, fortunately or unfortunately,
the bread reformers have not yet succeeded in inoculating
any considerable portion of the community with their doctrines,
and hence the actual food value of any sample
of wheat must be ascertained, not directly from the
composition of the wheat, but from the composition of the
flour made therefrom. Now, as already stated, phosphorus,
like the other mineral components, is found almost entirely
in the bran. Its presence in greater quantity, therefore,
simply adds to the testimony that a larger proportion of the
low grade wheat must be rejected than of the higher grade.
It should be evident to the complaining farmers that the
millers were in the right of the question, on this occasion at
least.

It is expected that further analysis will be made, this time
of the flour made from the different grades of wheat. If
these investigations be properly conducted, we have no
doubt that they will simply confirm the evidence of the
wheat tests. A chemical analysis alone, however, will not
be sufficient. The quantity of flour obtained from a given
amount of wheat must also be ascertained and its quality

further tested by means best known to millers, as regards
“doughing-up,” keeping qualities, color, etc. And then the
result can be no less than to show what millers already knew—that
the best quality of flour, commanding the top prices in
the market, cannot be obtained from an inferior quality of
wheat.—Milling World.

APPARATUS FOR PRINTING BY THE BLUE PROCESS.¹

By Channing Whitaker.

The blue process is well known to the members of the
society, and I need not take time to describe it; but with the
ordinary blue process printing frame the results are sometimes
unsatisfactory, and now that the process has come to
be so commonly used I have thought that an account of an
inexpensive but efficient printing frame would be of interest.
The essential parts of the apparatus are its frame, its glass,
its pad or cushion, its clamps, and the mechanism by which
the surface of the glass can easily be made to take a position
that is square with the direction of the sun’s rays.

The Blue Process Printing Frame in Common Use.—Its Defects.—The
pad of the apparatus in common use consists of
several thicknesses of blanketing stretched upon a back
board. The sensitized paper and the negative are placed
between the pad and the plate glass, and the whole is
squeezed together by pressure applied at the periphery of
the glass and of the back-board. Both the glass and the
back-board spring under the pressure, and it results that the
sensitized paper is not so severely pressed against the negative
near the center of the glass as it is near the edges. If
at any point the sensitized paper is not pressed hard up
against the negative, a bluish tinge will appear where a
white line or surface was expected. With an efficient
printing frame and suitable negatives, these blue lines will
never appear, and it was to prevent the production of defective
work that I undertook to improve the pad of the printing
frame.

The Printing Frame Used in Ordinary Photography.—Very
naturally, I first examined the printing frame used in ordinary
photography. This frame is extremely simple, and is very
well adapted to its use. It is, undoubtedly, the best frame for
blue process printing, when the area of the glass is not too
large. The glass is set in an ordinary wooden frame, while
the back-board is stiff and divided into two parts. A flat,
bow-shaped spring is attached by a pivot to the center of
each half of the back-board. The two halves of the back-board
are hinged together by ordinary butts. Four lugs are
fastened to the back of the frame, and, when the back-board
is placed in position, the springs may be swung around,
parallel to the line of the hinges, and pressed under the lugs,
so that the back of the back-board is pressed most severely
at the center of each half, while the glass is prevented from
springing away from the back-board by the resistance of the
frame at its edges. Unless the frame is remarkably stiff, it
will resist the springing of the glass more perfectly in the
neighborhood of the lugs than elsewhere. It will now be
seen that, on account of the manner in which the pressure
is applied, the back-board tends to become convex toward
the glass, while the adjacent surface of the glass tends to become
concave toward the back-board; and that with such a
frame, the pressure upon all parts of the sensitized paper is
more nearly uniform than when the pressure is applied in
the manner before described. With a small frame of this
description, a piece of ordinary cotton flannel is used between
the back-board and the sensitized paper, and, with
larger sizes, one or more thicknesses of elastic woolen blanket
are substituted for the cotton flannel. There is an advantage
in having a hinged back-board like that which has been
described, because, when the operator thinks that the exposure
to sunlight has been sufficiently prolonged, he can turn
down either half of the back and examine the sensitized
paper, to see if the process has been carried far enough. If
it has not, the back-board can be replaced, and the exposure
continued, without any displacement of the sensitized
paper with respect to the negative. This is an important advantage.

An Efficient Blue Process Frame, for Printing from Large
Negatives, or for Printing Simultaneously from many Small
Ones.—In order to be efficient, such a frame must be capable
of keeping the sensitized paper everywhere tightly pressed
against the negative. Again, such a frame, being large, is
necessarily somewhat heavy. It should be so mounted that
it can be handled with ease; and, in order that it may print
quickly, it should be so arranged that it can be turned
without delay, at any time, into a position that is square
with the direction of the sun’s rays.

Undoubtedly, if a sufficiently thick plate of glass should
be used, the ordinary photographic printing frames would
answer the purpose, whatever the size, but very thick plate
glass is both heavy and expensive. Commercial plate glass
varies in thickness from one-fourth to three eighths of an
inch, and the thicker plates are rather rare. A large plate
of it is easily broken by a slight uniformly distributed pressure.
But the pressure that is required for the blue process
printing, although slight, is much greater than is used in
the ordinary photographic process. For the sensitized
paper that is used in the blue process printing is, comparatively,
very thick and stiff, and it may cockle more or less,
while the paper that is used in ordinary photography is thin
and does not cockle. Now, it is easy to see that a pressure
severe enough to flatten all cockles must be had at every part
of the sensitized paper, and that, if the comparatively thin,
inexpensive, light weight, commercial plate glass is to be
used, it is desirable to have the pressure nowhere much greater
than is needed for that purpose, lest the fragile glass should
be fractured by it. In each of my large frames I use the
commercial plate glass; instead of the cushion of cotton flannel,
or of flannel, I use a cushion filled with air of sufficiently
high pressure to flatten all cockles, and to press all parts
of the sensitized paper closely against the negative; and instead
of the hinged back-board I use a back-board made in
one piece and clamped to the frame of the glass at its edges.
Connected with the cushion is a pressure gauge, and a tube
with a cock, for charging the cushion with air from the
lungs. Experience shows what pressure is necessary with
any given paper, and the gauge enables one to know that the
pressure is neither deficient nor in excess of that which is
safe for the glass.

PLAN. COTTON FLANNEL REMOVED.
SECTION AT CO.

The Construction of the Air-Cushion.—The expense of such
an air-cushion seemed at first likely to prevent its being used;
but a method of construction suggested itself, the expense
of which proved to be very slight. The wooden back-board,
as constructed, is made in one piece containing no wide
cracks. It has laid upon it some thick brown Manila paper,
the upper surface of which has been previously shellacked
to make it entirely air-tight. Upon this shellacked surface

is laid a single thickness of thin paper of any kind; even
newspaper will answer. Its object is simply to prevent the
sheet rubber, which forms the top of the air-cushion, from
sticking to the shellacked paper. The heat of the sun is
often sufficient to bring the shellac to a sticky state. It
would probably answer as well to shellac the under side of
the paper, and to use but one sheet, but I have not tried this
plan. Around the periphery of the pad, there is laid a piece
of rubber gasket about one and a half inches wide, and about
one-eighth of an inch thick. In order that the gasket may
not be too expensive, it is cut from two strips about three
inches wide. One of them is as long as the outside length
of the frame, and the other is as long as the outside width
of the frame. Each of these strips is cut into two L-shaped
pieces, an inch and a half in width, with the shorter leg of
each L three inches long. When the four pieces are put
together a scarf joint is made near each corner, having an
inch and one-half lap. It is somewhat difficult to cut such
a scarf joint as perfectly as one would wish, and it is best
to use rubber cement at the joints. Over the gasket is laid
a sheet of the thinnest grade of what is called pure rubber or
elastic gum. Above this, and over the gasket, is placed a
single thickness of cotton cloth, of the same dimensions as
the gasket, and yet above this are strips of ordinary strap
iron, an inch and a half wide and nearly one eighth of an
inch thick. These strips are filed square at the ends and
butt against each other at right angles. As the edges of the
strips are slightly rounded, they are filed away sufficiently
to form good joints wherever the others butt against them.
The whole combination is bound together by ordinary stove
bolts, one quarter of an inch in diameter, placed near the
center of the width of the iron strips, and at a distance apart
of about two and one-half inches. Their heads are countersunk
into the strap iron. In making the holes for the stove
bolts through the thin rubber, care should be taken to make
them sufficiently large to enable the bolt to pass through
without touching the rubber, otherwise the rubber may cling
to the bolts, and if they are turned in their holes the rubber
may be torn near the bolts and made to leak. A rough
washer, under each nut, prevents it from cutting into the
back-board. For the purpose of introducing air to, or removing
air from, the pad, a three-eighths of an inch lock
nut nipple is introduced through the back-board, the shellacked
paper, and its thin paper covering. Without the
back-board a T connects with the nipple. One of its
branches leads, by a rubber tube, to the pressure gauge,
which is a U-tube of glass containing mercury. The other
branch has upon it an ordinary plug cock, and, beyond this,
a rubber tube terminating in a glass mouth-piece. When it
is desired to inflate the air-cushion, it is only necessary to
blow into the mouth-piece. A pressure of one inch of mercury
is sufficient for any work that I have yet undertaken.
With particularly good paper, a lower pressure is sufficient.
Upon the top of the pad is laid a piece of common cotton
flannel with the nap outward, and with its edges tacked
along the under edge of the back-board. The cotton flannel
is not drawn tight across the top of the pad. The reason for
employing a cotton flannel covering is this: When the sheet
rubber has been exposed for a few days to the strong sunlight,
it loses its strength and becomes worthless. The cotton
flannel is a protection against the destruction of the rubber
by the sunlight. I first observed this destruction while experimenting
with a cheap and convenient form of gauge. I
used, as an inexpensive gauge, an ordinary toy balloon, and
I could tell, with sufficient accuracy, how much pressure I
had applied, by the swelling of the balloon. This balloon
ruptured from some unknown cause, and I made a substitute
for it out of a round sheet of thin flat rubber, gathered all
around the circumference. I made holes about one-quarter
of an inch apart, and passing a string in and out drew it
tight upon the outside of a piece of three eighths of an inch
pipe, I then wound a string tightly over the rubber, on the
pipe, and found the whole to be air-tight. This served me
for some time, but one day, on applying the pressure, I
found a hole in the balloon which looked as if it had been cut
with a very sharp knife. That it had been so cut was not
to be imagined, and on further examination I found that
the fracture had occured at a line which separated a surface
in the strong sunlight from a surface in the shade, at
a fold in the rubber. I saw that all of the rubber which had
been continuously exposed to the intense sunlight had
changed color and had become whiter than before, and
that that portion of the balloon had lost its strength. I
then returned to the use of the mercury gauge, and took the
precaution to cover my pad with cotton flannel, as a protection
from the light and from other sources of destruction.
This pad is upon the roof of the Institute; and is exposed to
all weathers. As a protection from the rain and the snow,
the whole is covered again with a rubber blanket. It has
withstood the exposure perfectly well for a year, without

injury. The gauge, made from flat rubber, is altogether so
cheap and so convenient that I am now experimenting
with one of this description having a black cloth covering
upon the outside. The balloon is of spherical shape, the
black cloth covering is of cylindrical shape, and I hope
that this device will serve every necessary purpose. A sectional
view of the air-cushion is offered as a part of this communication.

The Frame, which Contains the Plate Glass, is made of
thick board or plank, with the broad side of the board at
right angles to the surface of the glass. A rabbet is made
for the reception of the glass, and four strips of strap iron,
overlapping both the glass, and the wood, and screwed to
the wood, keep the glass in position. Strips of rubber are
interposed between the glass and the wood and between the
glass and the iron. The frame is hinged to the back-board
by separable hinges, so that the glass can be unhinged from
the pad without removing the screws. Hooks, such as are
used for foundry flasks, connect the frame with the pad
upon the opposite side. A frame made in this manner is
very stiff and springs but little, and its depth serves an excellent
purpose. The air-cushion and the frame are so
mounted that they can be easily turned to make the surface
of the glass square with the direction of the sun’s rays. It
is necessary to have a tell tale connected with the apparatus,
which will show when the surface of the glass has been thus
adjusted. The shadow of the deep frame is an inexpensive
tell-tale, and enables the operator to know when the adjustment
is right. I have now described, in detail, the construction
of the air-cushion with its back-board, as well as that
of the frame which holds the plate glass, and I think it will
be evident that the first cost of the materials of which they
are made is comparatively little, and that the workmanship
required to produce it is reduced to a minimum. It will
also, I think, be evident that a uniform pressure, of any desired
intensity, can be had all over the surface of the sensitized
paper for the purpose of securing perfect contact between
it and the negative. The blue copies that are taken
with this apparatus are entirely free from blue lines when the
negatives, chemicals, and paper are good.

The Mechanism for Adjusting the Surface of the Glass, until
it shall be Perpendicular to the Direction of the Sun’s Rays.—I
have found many uses for the blue copying process in connection
with the work of instruction at the Massachusetts
Institute of Technology. Notes printed by it are far better
and less costly than those printed by papyrograph. I will
not detain you now with an account of the uses that I have
made of it. I will merely say that more than a year ago I
found that my frame, which has a glass 3 feet x 4 feet, was
wholly inadequate to the work in hand, and I tried to increase
the production from it by diminishing the time of
printing. The glass of this frame was horizontal, except
when one of its ends was tilted off from the slides which
guided it when pushed out of the window; and I knew that
it took three or four times as long to print when the sun was
low as it did when the sun was near the meridian. I made
plans for mounting this frame upon a single axis, about
which it could be turned after it had been pushed through
the window, but I saw that no movement about a
single axis would give a satisfactory adjustment for all times
of the year, and I considered what arrangement of two axes
would permit a rapid and perfect adjustment, at all times,
with the least trouble to the operator. It was evident that
when the sun was in the equatorial plane, the surface
of the glass should contain a line which was parallel to the
axis of the earth; and further, that if such a glass was firmly
attached to an axis which was parallel to that of the earth,
it would fulfill the desired purpose. For the glass, being
once in adjustment, is only thrown out of position by the
rotation of the earth, and if the glass is rotated sufficiently
about its own axis, in a direction opposite to that of the
earth, it will retain its adjustment. In order to have the
adjustment equally good when the sun was either north or
south of the equatorial plane, it was sufficient to mount a
secondary axis upon the primary one and at right angles to
it. About this the glass could be turned through an angle of
23½°, either way, from the position which it should have
when the sun was in the equatorial plane.

BLUE PROCESS PRINTING APPARATUS.

The Construction of the Adjusting Mechanism.—I desired to
have the mechanism as compact and inexpensive as possible,
and to have the frame well balanced about the primary axis,
in every position. I also desired to have a rotation of nearly
180° about the principal axis. The plan adopted will be most
easily understood by referring to the drawing which illustrates
it. The axes are composed chiefly of wood. They
are built up from strips which are 3 inches x 7/8 inch, and
from small pieces of 2 inch plank. They are stiffly braced.
A pair of ordinary hinges permit the secondary rotation to
occur, while a pair of cast iron dowel pins with their sockets,
such as are used in foundry flasks, serve as pivots during the
primary rotation.

The Adjustments.—The adjustment about the secondary
axis does not need to be made more frequently than once a
week, or once a fortnight. In order to prevent rotation

about this axis when in adjustment, two cords lead from
points which are beneath the back board, and as far removed
from the secondary axis as is convenient. Each cord
passes forward and backward through four parallel holes in
a wooden block which is attached to the primary axis. The
cords can be easily slipped in the holes by pulling their
loops, but the friction is so great that they cannot be slipped
by pulling at either end. It takes about twice as long to
make the adjustment as would be necessary if a more expensive
device had been used; but this device is at once so cheap,
so secure, and has so seldom to be used, that it was thought
to be best adapted for the purpose. To prevent rotation
from occurring about the primary axis when it is not desired,
a bar parallel to the secondary axis is attached by its middle
point to the primary axis near one end. A cord passes from
either end of this bar through cam shaped clamps, which
were originally designed for clamping the cords of curtains
with spring fixtures. These clamps are cheap. They are
easily and quickly adjusted, and are very secure.

The whole apparatus can be located upon the roof of a
building, or, if convenient, it can be mounted upon slides,
and pushed through an open window when it is to be exposed
to the light. If it is to be used upon a roof, a small
hut, or shelter of some sort, near by is a great convenience
to the operator, particularly in winter.

An Inexpensive Drying Case for Use in Coating the Paper.—When
the apparatus is in continuous use, time may be saved
by having a convenient arrangement for drying the sheets
that have been coated with the sensitizing liquid. I have
made an inexpensive drying case which serves the purpose
very well. It consists simply of a light-tight rectangular case
of drawers. There are twenty-five drawers in all. They
are constructed in an inexpensive manner, and are the only
parts of the case that are worth describing. They are very
shallow, being but 1-7/8 inches deep, and as it appeared that
the principal expense would be for the materials of which
the bottoms of the drawers should be composed, it was decided
to make the bottoms of cotton cloth. This cloth is
stretched upon a frame, the dimensions of which are greater
than that of the paper to be dried. The stock of which the
frame is made is pine, 1¼ inches wide, and three-eighths of an
inch thick. The corners are simply mitered together and
attached to each other by means of the wire staples that are
commonly used for fastening together pages of manuscript,
and which are called “novelty staples.” Eight staples are
used at each miter, four above and four below the joint.
Two of the staples, at the top and near the ends of the joint,
are set square across it, and two others, at the top and near
the middle of the joint, are placed diagonally across it. The
staples at the bottom are similarly placed. The joint is quite
firm and strong, and is likely to hold for an indefinite period
with fair usage. The cloth, stretched upon the frame, is
fastened to it by means of similar staples. A dark colored
cloth not transparent to light is to be preferred. A strip of
pine, 1-13/16 inches wide, and three eighths of an inch thick,
forms the vertical front of the drawer, and prevents the admission
of much light from the front while the sheet is drying.
Two triangular knee pieces, three-quarters of an inch
thick, serve to connect the front board with the frame, and
four small screws with a few brads are used in attaching
them. The lower edge of the front board drops one-quarter
of an inch below the bottom of the drawer. My case stands in
a poorly lighted room, and paper dried in this case and removed
to a portfolio as soon as it is dry does not seem to be
injured by the light that reaches it. With the case in a well
lighted room, I should prefer to have outer doors to the case,
made of ordinary board six or eight inches wide, hinged to
one end, and arranged to swing horizontally across the front
of the case. These would more completely prevent the admission
of light. The opening of any one of the doors would
allow three or four of the drawers to be filled, while the
rest of the case would be comparatively dark at the same
time.²

The Portfolio for Protecting the Sensitized Paper from Exposure
to Light.—The sensitized paper is very well protected
from exposure to light, if kept in a portfolio or book, the
brown paper leaves of which are considerably larger than the
sensitized sheets. The sheets may be returned to such a
book after exposure, and washed at the convenience of the
operator. They can be washed more quickly and perfectly if
two water-tanks are provided in which to wash them. A
few minutes’ soaking will remove nearly all of the sensitizing
preparation which has not been fixed by the exposure. If
the soaking is too long continued in water that is much discolored
by the sensitizing preparation, the sheets become
saturated with the diluted preparation, and they may become
slightly colored by after exposure. If the first soaking is
not too long continued, and if the sheets are transferred at
once to a second bath of clean water, which is kept slowly
changing from an open faucet, they may remain there until
the soluble chemicals have been entirely extracted, and there
will be no risk of staining by after exposure. Washing
in two tanks is of more consequence when the ground is
white and the lines blue, than when the ground is blue and
the lines white.

The Grades of Paper that are well Adapted for Blue Process
Work.—I have tested many grades of paper, to ascertain if
they were well adapted for blue process work. Some grades
of brown Manila are very good; others have little specks embedded
in their surfaces which refuse to take on a blue tint;
still others, when printed upon, have white lines that are
wider than the corresponding black lines of the negative.
The blue obtained upon bond paper appears to be particularly
rich, and the whites remain pure; but bond paper
cockles badly, and the cockles remain in the finished print.
Weston’s linen record is an excellent paper. It is strong,
cockles but little, and dries very smooth. A paper that is
used by Allen & Rowell, for carbon printing, is comparatively
cheap, and is an excellent paper. It is not so stiff as
the linen record, and the whites are quite as pure. It does
not cockle, neither does it curl while being sensitized. It
comes in one hundred pound rolls, and is about thirty inches
wide. The best papers are those that are prepared for photographic
work. The plain Saxe and the plain Rives both
give excellent results. Blue lines on a pure white ground
can be obtained on these papers, from photographic negatives,
without difficulty. None of the hard papers of good
grade require the use of gum in the sensitizing liquid. The
liquid penetrates the more porous papers too far when gum
is not used, and without it good whites are seldom obtained
upon porous paper.

The Best Chemicals for this Work are the recrystallized red
prussiate of potash and the citrate of iron and ammonia,

which is manufactured by Powers & Wightman, of Philadelphia.
If the red prussiate has not been recrystallized, the
whites will be unsatisfactory and the samples of citrates of
iron and ammonia which have come to us from other
chemists than those named, have all proved unreliable for
this process.

The Sensitizing Liquid.—Its Proportions.—The blue process
was originally introduced from France, by the late Mr. A.
L. Holley. I was indebted to Mr. P. Barnes, who was with
Mr. Holley at the time, for an early account of it, and I had
the first blue process machine that was in use in New England.
Since 1876, instruction in the use of the blue process
has been given to the students of mechanical engineering of
the Massachusetts Institute of Technology, and they have
caused its introduction into many draughting offices. The
proportions of the sensitizing liquid, as originally given me
by Mr Barnes, were as follows:

Results of Experiments.—In our use, it first appeared that
the gum might be omitted from the preparation when
sufficiently hard papers were used. Next, that a preparation
containing

printed more rapidly. This preparation I continue to use
when much time may elapse between sensitizing and printing;
but, when the paper is to be printed immediately after
sensitizing, I use a larger proportion of citrate of iron and
ammonia. Before arriving at the conclusion that these
proportions were the best to be used, I made a series
of purely empirical experiments, beginning with the proportions:

and ending with the proportions:

I found the best plan for conducting these experiments to
be: To coat a sheet of the paper with a given mixture; to cut
the sheet into strips before exposure; to expose all the strips
of the sheet, at the same time, to the direct sunlight without
an intervening negative; and to withdraw them, one after
another, at stated intervals. I found that with each mixture
there was a time of exposure which would produce the
deepest blue, that with over-exposure the blue gradually
turned gray, and that if a curve should be plotted, the abscissas
of which should represent the time of exposure, and the
ordinates of which should represent the intensity of the blue
the curves drawn would have approximately an elliptical
form, so that if one knew the exact time of exposure which
would give the best result with any mixture, one might deviate
two or three minutes either way from that time without
producing a noticeable result. I have found that, with
the same paper, the same blue results with any good proportions
of the chemicals named, provided a sufficient weight
of both chemicals is applied to the surface; that an excess of
the red prussiate of potash renders the preparation less sensitive
to light, and very much lengthens the necessary time of
exposure; that the prints are finer with some excess of the
red prussiate; that an excess of the citrate of iron and
ammonia hastens the time of printing materially; that a
greater excess of the citrate causes the whites to become
badly stained by the iron, while a still greater excess of the
citrate, in a concentrated solution causes the sensitized
paper to change without exposure to light, and to produce a
redder blue or purple, which does not adhere to the paper,
but may be washed off with a sponge. I have found that
the cheapest method of reproducing inked drawings that
have been made on thick paper is not to trace them, but to
print the blues from a photographic glass negative; and also,
that the dry plate process is well adapted to such work in
offices, when one has become sufficiently experienced. Printed
matter can also most easily and inexpensively be reproduced
by the same means, when a small issue is required on each
successive year. For the reproduction of manuscript by the
blue process, the best plan that I have found has been to write
the manuscript upon the thinnest blue tinted French note-paper,
with black opaque ink—the stylographic ink is very
good—and, afterward, to dip the paper into melted paraffine,
and to dry the paper at the melting temperature. This operation,
if cheaply done, requires special apparatus. For positive
printing from the glass negative, I use a multiple frame,
by the aid of which I can print from 16 negatives at the same
time, upon a single sheet of paper. This frame is interchangeable
with the one that contains the plate glass. The
negatives are so arranged in the frame that the sheets can
be cut and bound, as in the ordinary process of book binding.
The time required for exposure, when printing from glass
negatives, varies with the negative; and, in order to secure
satisfactory results with the multiple frame it is necessary
to stop the exposure of some, while the exposure of others is
continued. I insert wooden or cloth stoppers into the frame
for the purpose of stopping the exposure of certain negatives.
When paraffined manuscript is to be printed from, I find it convenient
to have it written on sheets of small size, and to have
these mounted upon an opaque frame of brown Manila paper,
printing sixteen or more at a time, depending upon the size
of the printing frame. Many small tracings may be similarly
mounted upon a brown paper multiple frame, and may be
printed together upon a single sheet.

[1]

[2]

SPECTRUM GRATINGS.

At a recent meeting of the London Physical Society,
Prof. Rowland, of Baltimore, exhibited a number of his new
concave gratings for giving a diffraction spectrum. He explained
the theory of their action. Gratings can be ruled
on any surface, if the lines are at a proper distance apart and
of the proper form. The best surface, however, is a cylindrical
or spherical one. The gratings are solid slabs of
polished speculum metal ruled with lines equidistant by a
special machine of Prof. Rowland’s invention. An account
of this machine will be published shortly. The number of
lines per inch varied in the specimens shown from 5,000 to
42,000, but higher numbers can be engraved by the cutting
diamond. The author has designed an ingenious mechanical
arrangement for keeping the photographic plates in focus.
In this way photographs of great distinctness can be obtained.
Prof. Rowland exhibited some 10 inches long, which showed

the E line doubled, and the large B group very clearly.
Lines are divided by this method which have never been
divided before, and the work of photographing takes a mere
fraction of the time formerly required. A photographic
plate sensitive throughout its length is got by means of a
mixture of eosene, iodized collodion, and bromized collodion.
Prof. Rowland and Captain Abney, R.E., are at present
engaged in preparing a new map of the whole spectrum with
a focus of 18 feet.

In reply to Mr. Hilger, F.R.A.S., the author stated that
if the metal is the true speculum metal used by Lord Rosse,
it would stand the effects of climate, he thought; but if too
much copper were put in, it might not.

In reply to Mr. Warren de la Rue, Prof. Rowland said
that 42,000 was the largest number of lines he had yet required
to engrave on the metal.

Prof. Guthrie read a letter from Captain Abney, pointing
out that Prof. Rowland’s plates gave clearer spectra than any
others; they were free from “ghosts,” caused by periodicity
in the ruling, and the speculum metal had no particular
absorption.

Prof. Dewar, F.R.S., observed that Prof. Liveing and he
had been engaged for three years past in preparing a map of
the ultra-violet spectrum, which would soon be published.
He considered the concave gratings to make a new departure
in the subject, and that they would have greatly facilitated
the preparation of his map.

A NEW POCKET OPERA GLASS.

POCKET OPERA GLASS.

Inasmuch as high power combined with small size is
usually required in an opera glass, manufacturers have always
striven to unite these two features in their instruments,
and have succeeded in producing glasses which, although
sufficiently small to be carried in the waistcoat pocket, are
nevertheless powerful enough to allow quite distant objects
to be clearly distinguished. Recently, a Parisian optician
has succeeded in constructing an instrument of this kind
that is somewhat of a novelty in its way, since its mechanism
allows it to be closed in such a manner as to take up no
more space than a package of cigarettes (Fig. 1.) It is constructed
as follows:

AB and CD (Fig. 1) are two metallic tubes, in which slide
with slight friction two other tubes. Into the upper part of
the latter are inserted two hollow elliptical eye-pieces, which
move therein with slight friction, and which are united by the
two supports tor the wheel, bb (Fig. 4), and endless screw
that serve for focusing the instrument. The eyepieces,
TT, are held in the tube by means of two screws, vv
(Figs. 2 and 4), in such a way that they can revolve around
the latter as axes. The lenses of the eye-piece are
fixed therein by means of a copper ring. The object
glasses are placed in the ends of the tubes, AB and CD, at
oo.

When the instrument is closed, it forms a cylinder 35 millimeters
in diameter by 11 centimeters in length. To open it,
it is grasped by the extremities and drawn apart horizontally
so as to bring it into the position shown in Fig. 2. Then it
is turned over so that the screw, V, points upward, while at
the same time the two tubes are pressed gently downward.
This causes the eye-pieces to revolve around their axes, vv,
and brings the two tubes parallel with each other.—La
Nature.

ANCIENT GREEK PAINTING.

A lecture on ancient Greek painting was lately delivered by
Professor C.T. Newton, C.B., at University College, London.
The lecturer began by reminding his audience of the course of
lectures on Greek sculpture, from the earliest times to the
Roman period, which he completed this year. The main
epochs in the history of ancient sculpture had an intimate
connection with the general history of the Greeks, with their
intellectual, political, and social development. We could
not profitably study the history of ancient sculpture except
as part of the collateral study of ancient life as a whole, nor
could we get a clear idea of the history of ancient sculpture
without tracing out, so far as our imperfect knowledge
permits, the characteristics and successive stages of ancient
painting. Between these twin sister arts there had been in

all times, and especially in Greek antiquity, a close sympathy
and a reciprocal influence. The method in dealing with the
history of Greek painting in this course would be similar to
that adopted in the course on sculpture. The evidence of
ancient authors as to the works and characteristics of Greek
painters would be first examined, then the extant monuments
which illustrate the history of this branch of art would be
described. In the case of painting, the extant monuments
were few and far between, but we might learn much by the
careful study of the mural paintings from the buried Campanian
cities, Pompeii, Herculaneum, and those found in the
tombs near Rome and Etruria. The paintings on Greek
vases would enable us to trace the history of what is called
ceramographic art from B.C. 600 for nearly five centuries onward.

After noticing the traditions preserved by Pliny and
others as to the earliest painters, the lecturer passed on to
the period after the Persian war. Polygnotos of Thasos
was the earliest Greek painter of celebrity. He flourished
B.C. 480-460. At Athens he decorated with paintings the
portico called the Stoa Poikile, the Temple of the Dioscuri,
the Temple of Theseus, and the Pinakotheke on the Akropolis.
At Delphi he painted on the walls of the building
called Lesche two celebrated pictures, the taking of Troy
and the descent of Ulysses into Hades. All these were mural
paintings; the subjects were partly mythical, partly historical.
Thus in the Stoa Poikile were represented the taking
of Troy, the battle of Theseus with the Amazons, the battle
of Marathon. In the Temple of Theseus came the battle of the
Lapiths and Centaurs and the battle of the Amazons again.
In the other two Athenian temples he treated mythological
subjects. These great public works were executed during
the administration of Kimon, to whom Polygnotos stood in
the same relation us Phidias did to Perikles, the successor of
Kimon. The paintings in the Stoa Poikile were executed by
Polygnotos gratuitously, for which service the Athenians rewarded
him with the freedom of their city. His greatest and
probably his earliest works were the two pictures in the
Lesche at Delphi. Of these there was a very full description
in Pausanias. The building called Lesche was thought to have
been of elliptical form, with a colonnade on either side, separated
by a wall in the middle, and to have been about 90 ft in
length. The figures were probably life size.

According to the list given by Pausanias, there were upward
of seventy in each of the two pictures. In that representing
the taking of Troy Polygnotos had brought together many
incidents described in the Cyclic epics: Menelaos Agamemnon,
Ulysses, Nestor, Neoptolemos, Antenor, Helen, Andromache,
Kassandra, and many other figures, with which the
Homeric poems have made us familiar, all appeared united
in one skillful composition, arranged in groups. The other
picture, the descent of Ulysses into Hades to interrogate
Teiresias, might be called a pictorial epic of Hades. On
one side was the entrance, indicated by Charon’s boat crossing:
the Acheron, and the evocation of Teiresias by Ulysses,
besides the punishment of Tityos and other wicked men;
on the other side were Tantalos and Sisyphos. Between these
scenes, on the flanks, were various groups of heroes and
heroines from the Trojan and other legends. From the remarks
of ancient critics, it might be inferred that the genius
of Polygnotos, like that of Giotto, was far in advance of his
technical skill. Aristotle called him the most ethical of
painters, and recommended the young artist to study his
works in preference to those of his contemporary Pauson,
who was ignobly realistic, or those of Zeuxis, who had great
technical merit, but was deficient in spiritual conception.
The course will comprise four more lectures, as follows—November
17, “Greek Painters from B.C. 460 to Accession of
Alexander the Great B.C. 336—Apollodoros, Zeuxis, Parrhasios,
Pamphilos, Aristides;” November 24, “Greek
Painters from Age of Alexander to Augustan Age—Apelles,
Protogenes, Theon;” December 1, “Pictures on Greek Fictile
Vases;” December 15, “Mural Paintings from Pompeii,
Herculaneum, and other Ancient sites.”

The new Iowa State Capitol has thus far cost $2,000,000,
and it will require $500,000 to finish it. It is 365 feet long
fron north to south, and measures 274 feet from the sidewalk
to the top of the central dome.

[LONGMAN’S MAGAZINE.]

ATOMS, MOLECULES, AND ETHER WAVES.

By John Tyndall, F.R.S.

I.

Man is prone to idealization. He cannot accept as final
the phenomena of the sensible world, but looks behind that
world into another which rules the sensible one. From this
tendency of the human mind, systems of mythology and scientific
theories have equally sprung. By the former the experiences
of volition, passion, power, and design, manifested
among ourselves, were transplanted, with the necessary
modifications, into an unseen universe from which the sway
and potency of those magnified human qualities were exerted.
“In the roar of thunder and in the violence of the
storm was felt the presence of a shouter and furious strikers,
and out of the rain was created an Indra or giver of rain.”
It is substantially the same with science, the principal force
of which is expended in endeavoring to rend the veil which
separates the sensible world from an ultra-sensible one. In
both cases our materials, drawn from the world of the senses,
are modified by the imagination to suit intellectual needs.
The “first beginnings” of Lucretius were not objects of
sense, but they were suggested and illustrated by objects of
sense. The idea of atoms proved an early want on the part
of minds in pursuit of the knowledge of nature. It has
never been relinquished, and in our own day it is growing
steadily in power and precision.

The union of bodies in fixed and multiple proportions constitutes
the basis of modern atomic theory. The same compound
retains, for ever, the same elements, in an unalterable
ratio. We cannot produce pure water containing one part,
by weight, of hydrogen and nine of oxygen, nor can we
produce it when the ratio is one to ten; but we can produce
it from the ratio of one to eight, and from no other. So also
when water is decomposed by the electric current, the proportion,
as regards volumes, is as fixed as in the case of
weights. Two volumes of hydrogen and one of oxygen invariably
go the formation of water. Number and harmony,
as in the Pythagorean system, are everywhere dominant in
this under-world.

Following the discovery of fixed proportions we have that
of multiple proportions. For the same compound, as above
stated, the elementary factors are constant; but one elementary
body often unites with another so as to form different
compounds. Water, for example, is an oxide of hydrogen;
but a peroxide of that substance also exists, containing exactly
double the quantity of oxygen. Nitrogen also unites
with oxygen in various ratios, but not in all. The union
takes place, not gradually and uniformly, but by steps, a
definite weight of matter being added at each step. The
larger combining quantities of oxygen are thus multiples
of the smaller ones. It is the same with other combinations.

We remain thus far in the region of fact: why not rest
there? It might as well be asked why we do not, like our
poor relations of the woods and forests, rest content with
the facts of the sensible world. In virtue of our mental
idiosyncrasy, we demand why bodies should combine in
multiple proportions, and the outcome and answer of this
question is the atomic theory. The definite weights of matter,
above referred to, represent the weights of atoms, indivisible
by any force which chemistry has hitherto brought
to bear upon them. If matter were a continuum—if it were
not rounded off, so to say, into these discrete atomic masses—the
impassable breaches of continuity which the law of
multiple proportions reveals, could not be accounted for.
These atoms are what Maxwell finely calls “the foundation
stones of the material universe,” which, amid the wreck of
composite matter, “remain unbroken and unworn.”

A group of atoms drawn and held together by what chemists
term affinity is called a molecule. The ultimate parts
of all compound bodies are molecules. A molecule of water,
for example, consists of two atoms of hydrogen, which grasp
and are grasped by one atom of oxygen. When water is
converted into steam, the distances between the molecules
are greatly augmented, but the molecules themselves continue
intact. We must not, however, picture the constituent
atoms of any molecule as held so rigidly together as to render
intestine motion impossible. The interlocked atoms
have still liberty of vibration, which may, under certain
circumstances, become so intense as to shake the molecule
asunder. Most molecules—probably all—are wrecked by
intense heat, or in other words by intense vibratory motion;
and many are wrecked by a very moderate heat of the proper
quality. Indeed, a weak force, which bears a suitable
relation to the constitution of the molecule, can, by timely
savings and accumulations, accomplish what a strong force
out of relation fails to achieve.

We have here a glimpse of the world in which the physical
philosopher for the most part resides. Science has been defined
as “organized common sense;” by whom I have forgotten;
but, unless we stretch unduly the definition of common
sense, I think it is hardly applicable to this world of
molecules. I should be inclined to ascribe the creation of
that world to inspiration rather than to what is currently
known as common sense. For the natural history sciences
the definition may stand—hardly for the physical and mathematical
sciences.

The sensation of light is produced by a succession of waves
which strike the retina in periodic intervals; and such waves,
impinging on the molecules of bodies, agitate their constituent
atoms. These atoms are so small, and, when
grouped to molecules, are so tightly clasped together, that
they are capable of tremors equal in rapidity to those of
light and radiant heat. To a mind coming freshly to these
subjects, the numbers with which scientific men here habitually
deal must appear utterly fantastical; and yet, to minds
trained in the logic of science, they express most sober and
certain truth. The constituent atoms of molecules can vibrate
to and fro millions of millions of times in a second.
The waves of light and of radiant heat follow each other at
similar rates through the luminiferous ether. Further, the
atoms of different molecules are held together with varying
degrees of tightness—they are tuned, as it were, to notes of
different pitch. Suppose, then, light-waves, or heat-waves,
to impinge upon an assemblage of such molecules, what
may be expected to occur? The same as what occurs when
a piano is opened and sung into. The waves of sound select
the strings which respectively respond to them—the strings,
that is to say, whose rates of vibration are the same as their
own—and of the general series of strings these only sound.
The vibratory motion of the voice, imparted first to the air,
is here taken up by the strings. It may be regarded as absorbed,
each string constituting itself thereby a new center of
motion. Thus also, as regards the tightly locked atoms of
molecules on which waves of light or radiant heat impinge.

Like the waves of sound just adverted to, the waves of ether
select those atoms whose periods of vibration synchronize
with their own periods of recurrence, and to such atoms deliver
up their motion. It is thus that light and radiant heat
are absorbed.

And here the statement, though elementary, must not be
omitted, that the colors of the prismatic spectrum, which are
presented in an impure form in the rainbow, are due to different
rates of atomic vibration in their source, the sun.
From the extreme red to the extreme violet, between which
are embraced all colors visible to the human eye, the rapidity
of vibration steadily increases, the length of the waves of
ether produced by these vibrations diminishing in the same
proportion. I say “visible to the human eye,” because
there may be eyes capable of receiving visual impression
from waves which do not affect ours. There is a vast store
of rays, or more correctly waves, beyond the red, and also
beyond the violet, which are incompetent to excite our vision;
so that could the whole length of the spectrum, visible
and invisible, be seen by the same eye, its length would be
vastly augmented.

I have spoken of molecules being wrecked by a moderate
amount of heat of the proper quality: let us examine this
point for a moment. There is a liquid called nitrite of amyl—frequently
administered to patients suffering from heart
disease. The liquid is volatile, and its vapor is usually inhaled
by the patient. Let a quantity of this vapor be introduced
into a wide glass tube, and let a concentrated beam
of solar light be sent through the tube along its axis. Prior
to the entry of the beam, the vapor is as invisible as the purest
air. When the light enters, a bright cloud is immediately
precipitated on the beam. This is entirely due to the
waves of light, which wreck the nitrite of amyl molecules,
the products of decomposition forming innumerable liquid
particles which constitute the cloud. Many other gases and
vapors are acted upon in a similar manner. Now the waves
that produce this decomposition are by no means the most
powerful of those emitted by the sun. It is, for example,
possible to gather up the ultra-red waves into a concentrated
beam, and to send it through the vapor, like the beam of light.
But, though possessing vastly greater energy than the light
waves, they fail to produce decomposition. Hence the justification
of the statement already made, that a suitable relation
must subsist between the molecules and the waves of
ether to render the latter effectual.

A very impressive illustration of the decomposing power
of the waves of light is here purposely chosen; but the processes
of photography illustrate the same principle. The
photographer, without fear, illuminates his developing room
with light transmitted through red or yellow glass; but he
dares not use blue glass, for blue light would decompose his
chemicals. And yet the waves of red light, measured by the
amount of energy which they carry, are immensely more
powerful than the waves of blue. The blue rays are usually
called chemical rays—a misleading term; for, as Draper and
others have taught us, the rays that produce the grandest
chemical effects in nature, by decomposing the carbonic
acid and water which form the nutriment of plants, are not
the blue ones. In regard, however, to the salts of silver,
and many other compounds, the blue rays are the most
effectual. How is it then that weak waves can produce
effects which strong waves are incompetent to produce?
This is a feature characteristic of periodic motion. In the
experiment of singing into an open piano already referred
to, it is the accord subsisting between the vibrations of the
voice and those of the string that causes the latter to sound.
Were this accord absent, the intensity of the voice might be
quintupled, without producing any response. But when
voice and string are identical in pitch, the successive impulses
add themselves together, and this addition renders
them, in the aggregate, powerful, though individually they
may be weak. It some such fashion the periodic strokes of
the smaller ether waves accumulate, till the atoms on which
their timed impulses impinge are jerked asunder, and what
we call chemical decomposition ensues.

Savart was the first to show the influence of musical sounds
upon liquid jets, and I have now to describe an experiment
belonging to this class, which bears upon the present question.
From a screw-tap in my little Alpine kitchen I permitted,
an hour ago, a vein of water to descend into a
trough, so arranging the flow that the jet was steady and
continuous from top to bottom. A slight diminution of the
orifice caused the continuous portion of the vein to shorten,
the part further down resolving itself into drops. In my
experiment, however, the vein, before it broke, was intersected
by the bottom of the trough. Shouting near the descending
jet produced no sensible effect upon it. The higher
notes of the voice, however powerful, were also ineffectual.
But when the voice was lowered to about 130 vibrations a
second, the feeblest utterance of this note sufficed to shorten,
by one half, the continuous portion of the jet. The responsive
drops ran along the vein, pattered against the trough,
and scattered a copious spray round their place of impact.
When the note ceased, the continuity and steadiness of the
vein were immediately restored. The formation of the drops
was here periodic; and when the vibrations of the note accurately
synchronized with the periods of the drops, the
waves of sound aided what Plateau has proved to be the
natural tendency of the liquid cylinder to resolve itself into
spherules, and virtually decomposed the vein.

I have stated, without proof, that where absorption occurs,
the motion of the ether-waves is taken up by the constituent
atoms of molecules. It is conceivable that the ether-waves,
in passing through an assemblage of molecules, might deliver
up their motion to each molecule as a whole, leaving
the relative positions of the constituent atoms unchanged.
But the long series of reactions, represented by the deportment
of nitrite of amyl vapor, does not favor this conception;
for, were the atoms animated solely by a common
motion, the molecules would not be decomposed. The fact of
decomposition, then, goes to prove the atoms to be the
seat of the absorption. They, in great part, take up the
energy of the ether-waves, whereby their union is severed,
and the building materials of the molecules are scattered
abroad.

Molecules differ in stability; some of them, though hit by
waves of considerable force, and taking up the motions of
these waves, nevertheless hold their own with a tenacity
which defies decomposition. And here, in passing, I may
say that it would give me extreme pleasure to be able to
point to my researches in confirmation of the solar theory
recently enunciated by my friend the President of the British
Association. But though the experiments which I have
made on the decomposition of vapors by light might be
numbered by the thousand, I have, to my regret, encountered
no fact which prove that free aqueous vapor is decomposed
by the solar rays, or that the sun is reheated by the
combination of gases, in the severance of which it had previously
sacrificed its heat.

II.

The memorable investigations of Leslie and Rumford, and
the subsequent classical reasearches of Melloni, dealt, in the
main, with the properties of radiant heat; while in my investigations,
radiant heat, instead of being regarded as an
end, was employed as a means of exploring molecular condition.
On this score little could be said until the gaseous
form of matter was brought under the dominion of experiment.
This was first effected in 1859, when it was proved
that gases and vapors, notwithstanding the open door which
the distances between their molecules might be supposed to
offer to the heat waves, were, in many cases, able effectually
to bar their passage. It was then proved that while the
elementary gases and their mixtures, including among the
latter the earth’s atmosphere, were almost as pervious as a
vacuum to ordinary radiant heat, the compound gases were
one and all absorbers, some of them taking up with intense
avidity the motion of the ether-waves.

A single illustration will here suffice. Let a mixture of
hydrogen and nitrogen, in the proportion of three to fourteen
by weight, be inclosed in a space through which are passing
the heat rays from an ordinary stove. The gaseous mixture
offers no measurable impediment to the rays of heat.
Let the hydrogen and nitrogen now unite to form the compound
ammonia. A magical change instantly occurs. The
number of atoms present remains unchanged. The transparency
of the compound is quite equal to that of the mixture
prior to combination. No change is perceptible to the eye,
but the keen vision of experiment soon detects the fact that
the perfectly transparent and highly attenuated ammonia
resembles pitch or lampblack in its behavior to the rays of
heat.

There is probably boldness, if not rashness, in the attempt
to make these ultra-sensible actions generally intelligible,
and I may have already transgressed the limits beyond which
the writer of a familiar article cannot profitably go. There
may, however, be a remnant of readers willing to accompany
me, and for their sakes I proceed. A hundred compounds
might be named which, like the ammonia, are transparent to
light, but more or less opaque—often, indeed, intensely
opaque—to the rays of heat from obscure sources. Now the
difference between these latter rays and the light rays is
purely a difference of period of vibration. The vibrations in
the case of light are more rapid, and the ether waves which
they produce are shorter, than in the case of obscure heat.
Why, then, should the ultra-red waves be intercepted by bodies
like ammonia, while the more rapidly recurrent waves
of the whole visible spectrum are allowed free transmission?
The answer I hold to be that, by the act of chemical combination,
the vibrations of the constituent atoms of the molecules
are rendered so sluggish as to synchronize with the
motions of the longer waves. They resemble loaded piano
strings, or slowly descending water jets, requiring notes of
low pitch to set them in motion.

The influence of synchronism between the “radiant” and
the “absorbent” is well shown by the behavior of carbonic
acid gas. To the complex emission from our heated stove,
carbonic acid would be one of the most transparent of gases.
For such waves olefiant gas, for example, would vastly transcend
it in absorbing power. But when we select a radiant
with whose waves the atoms of carbonic acid are in accord,
the case is entirely altered. Such a radiant is found in a
carbonic oxide flame, where the radiating body is really hot
carbonic acid. To this special radiation carbonic acid is the
most opaque of gases.

And here we find ourselves face to face with a question of
great delicacy and importance. Both as a radiator and as an
absorber, carbonic acid is, in general, a feeble gas. It is
beaten in this respect by chloride of methyl, ethylene, ammonia,
sulphurous acid, nitrous oxide, and marsh gas. Compared
with some of these gases, its behavior, in fact, approaches
that of elementary bodies. May it not help to
explain their neutrality? The doctrine is now very generally
accepted that atoms of the same kind may, like atoms
of different kinds, group themselves to molecules. Affinity
exists between hydrogen and hydrogen and between chlorine
and chlorine, as well as between hydrogen and chlorine.
We have thus homogeneous molecules as well as heterogeneous
molecules, and the neutrality so strikingly exhibited by
the elements may be due to a quality of which carbonic acid
furnishes a partial illustration. The paired atoms of the
elementary molecules may be so out of accord with the periods
of the ultra red waves—the vibrating periods of these
atoms may, for example, be so rapid—as to disqualify them
both from emitting those waves, and from accepting their
energy. This would practically destroy their power, both as
radiators and absorbers. I have reason to know that a distinguished
authority has for some time entertained this hypothesis.

We must, however, refresh ourselves by occasional contact
with the solid ground of experiment, and an interesting
problem now lies before us awaiting experimental solution.
Suppose two hundred men to be scattered equably throughout
the length of Pall Mall. By timely swerving now and
then, a runner from St. James’s Palace to the Athenæum
Club might be able to get through such a crowd without
much hinderance. But supposing the men to close up so as
to form a dense file crossing Pall Mall from north to south;
such a barrier might seriously impede, or entirely stop, the
runner. Instead of a crowd of men, let us imagine a column
of molecules under small pressure, thus resembling the
sparsely distributed crowd. Let us suppose the column to
shorten, without change in the quantity of matter, until the
molecules are so squeezed together as to resemble the closed
file across Pall Mall. During these changes of density,
would the action of the molecules upon a beam of heat passing
among them at all resemble the action of the crowd
upon the runner?

We must answer this question by direct experiment. To
form our molecular crowd we place, in the first instance, a
gas or vapor in a tube 38 inches long, the ends of which are
closed with circular windows, air-tight, but formed of a substance
which offers little or no obstruction to the calorific
waves. Calling the measured value of a heat beam passing
through this tube 100, we carefully determine the proportionate
part of this total absorbed by the molecules in the
tube. We then gather precisely the same number of molecules
into a column 10.8 inches long, the one column being
thus three and a half times the length of the other. In this
case also we determine the quantity of radiant heat absorbed.
By the depression of a barometric column, we can easily and
exactly measure out the proper quantities of the gaseous
body. It is obvious that one mercury inch of vapor, in the
long tube, would represent precisely the same amount of
matter—or, in other words, the same number of molecules—as
3½ inches in the short one; while 2 inches of vapor in
the long tube would be equivalent to 7 inches in the short
one.

The experiments have been made with the vapors of two
very volatile liquids, namely, sulphuric ether and hydride
of amyl. The sources of radiant heat were, in some cases,
an incandescent lime cylinder, and in others a spiral of
platinum wire, heated to bright redness by an electric
current. One or two of the measurements will suffice
for the purposes of illustration. First, then, as regards
the lime light; for 1 inch of pressure in the long tube,
the absorption was 18.4 per cent. of the total beam; while
for 3.5 inches of pressure in the short tube, the absorption
was 18.8 per cent., or almost exactly the same as the
former. For 2 inches pressure, moreover, in the long tube,
the absorption was 25.7 per cent.; while for 7 inches in the
short tube it was 25.6 per cent. of the total beam. Thus
closely do the absorptions in the two cases run together—thus
emphatically do the molecules assert their individuality.
As long as their number is unaltered, their action on radiant
heat is unchanged. Passing from the lime light to the
incandescent spiral, the absorptions of the smaller equivalent
quantities, in the two tubes, were 23.5 and 23.4 per
cent.; while the absorptions of the larger equivalent quantities
were 32.1 and 32.6 per cent., respectively. This constancy
of absorption, when the density of a gas or vapor
is varied, I have called “the conservation of molecular action.”

But it may be urged that the change of density, in these
experiments, has not been carried far enough to justify the
enunciation of a law of molecular physics. The condensation
into less than one-third of the space does not, it may be
said, quite represent the close file of men across Pall Mall.
Let us therefore push matters to extremes, and continue the
condensation till the vapor has been squeezed into a liquid.
To the pure change of density we shall then have added the
change in the state of aggregation. The experiments here
are more easily described than executed; nevertheless, by
sufficient training, scrupulous accuracy, and minute attention
to details, success may be insured. Knowing the respective
specific gravities, it is easy, by calculation, to determine
the condensation requisite to reduce a column of vapor
of definite density and length to a layer of liquid of definite
thickness. Let the vapor, for example, be that of sulphuric
ether, and let it be introduced into our 38 inch tube till a
pressure of 7.2 inches of mercury is obtained. Or let it be
hydride of amyl, of the same length, and at a pressure of 6.6
inches. Supposing the column to shorten, the vapor would
become proportionally denser, and would, in each case, end
in the production of a layer of liquid exactly one millimeter
in thickness.¹ Conversely, a layer of liquid ether or of hydride
of amyl, of this thickness, were its molecules freed
from the thrall of cohesion, would form a column of vapor
38 inches long, at a pressure of 7.2 inches in the one case,
and of 6.6 inches in the other. In passing through the liquid
layer, a beam of heat encounters the same number of molecules
as in passing through the vapor layer: and our problem
is to decide, by experiment, whether, in both cases, the
molecule is not the dominant factor, or whether its power is
augmented, diminished, or otherwise overridden by the state
of aggregation.

Using the sources of heat before mentioned, and employing
diathermanous lenses, or silvered minors, to render the
rays from those sources parallel, the absorption of radiant
heat was determined, first for the liquid layer, and then for
its equivalent vaporous layer. As before, a representative
experiment or two will suffice for illustration. When the
substance was sulphuric ether, and the source of radiant
heat an incandescent platinum spiral, the absorption by the
column of vapor was found to be 66.7 per cent. of the total
beam. The absorption of the equivalent liquid layer was
next determined, and found to be 67.2 per cent. Liquid and
vapor, therefore, differed from each only 0.5 per cent.; in
other words, they were practically identical in their action.
The radiation from the lime light has a greater power of penetration
through transparent substances than that from the
spiral. In the emission from both of these sources we have
a mixture of obscure and luminous rays; but the ratio of
the latter to the former, in the lime light is greater than in
the spiral; and, as the very meaning of transparency is perviousness
to the luminous rays, the emission in which these
rays are predominant must pass most freely through transparent
substances. Increased transmission implies diminished
absorption; and accordingly, the respective absorption of
ether vapor and liquid ether, when the lime light was used,
instead of being 66.7 and 67.2 per cent., were found to be

no difference whatever being observed between the two
states of aggregation. The same was found true of hydride
of amyl.

This constancy and continuity of the action exerted on the
waves of heat when the state of aggregation is changed, I
have called “the thermal continuity of liquids and vapors.”
It is, I think, the strongest illustration hitherto adduced of
the conservation of molecular action.

Thus, by new methods of search, we reach a result which
was long ago enunciated on other grounds. Water is well
known to be one of the most opaque of liquids to the waves
of obscure heat. But if the relation of liquids to their vapors
be that here shadowed forth, if in both cases the molecule
asserts itself to be the dominant factor, then the dispersion
of the water of our seas and rivers, as invisible aqueous vapor
in our atmosphere, does not annul the action of the
molecules on solar and terrestrial heat. Both are profoundly
modified by this constituent; but as aqueous vapor is transparent,
which, as before explained, means pervious to the
luminous rays, and as the emission from the sun abounds in
such rays, while from the earth’s emission they are wholly
absent, the vapor screen offers a far greater hinderance to
the outflow of heat from the earth toward space than to the
inflow from the sun toward the earth. The elevation of
our planet’s temperature is therefore a direct consequence of
the existence of aqueous vapor in our air. Flimsy as that
garment may appear, were it removed terrestrial life would
probably perish through the consequent refrigeration.

I have thus endeavored to give some account of a recent
incursion into that ultra-sensible world mentioned at the
outset of this paper. Invited by my publishers, with whom
I have now worked in harmony for a period of twenty
years, to send some contribution to the first number of their
new Magazine, I could not refuse them this proof of my
good will.

J. TYNDALL

Alp Lusgen, September 4, 1882

[1]

The German empire has now about 34,000,000 acres of
forest, valued at $400,000,000, and appropriates $500,000
even year to increase and maintain the growth of trees.

APPARATUS FOR MEASURING ELECTRICITY AT THE UPPER SCHOOL OF TELEGRAPHY.

Electro Tuning Forks and their Uses.—On a former occasion
I described an instrument to which, in 1873, I gave the
name Electro-Tuning Fork, and which is nothing else than a
tuning fork whose motion is kept up electrically in such a
way as to last indefinitely, provided that the elements of the
pile are renewed gradually, and that from time to time the
metallic contact is changed, which causes, at every oscillation,
the current to pass from the pile into the magnet, which
keeps up the vibration.

We reproduce herewith, in Fig. 1, a cut showing in projection
one of the simplest forms of the apparatus.

FIG. 1.—CONSTANT VIBRATOR.

If we imagine the platinum or steel style, s, of the figure
to be done away with, as well as the platinized plate, I, and
its communication with the negative pole of the pile, P, we
shall have the ordinary instrument kept in operation electrically
by the aid of the electro-magnet, E, the style, s, the interrupting
plate, I, and the pile.

If we preserve the parts above mentioned, the instrument
will possess the property of having vibrations of a constant
amplitude if sufficient energy be kept up in the pile. In
fact, when the amplitude is sufficiently great to cause the
style, s, to touch the plate, I, it will be seen that at such a
moment the current no longer passes through the electromagnet,
and the vibration is no longer maintained. The
amplitude cannot exceed an extent which shall permit the
style, s, to touch I.

Under such conditions, the duration of the vibrations remains
exactly constant, as does also the vibratory intensity

of the entire instrument. The measurement of time, then,
by an instrument of this kind is, indeed, as perfect as it could
well be.

This complication in the arrangement of the apparatus has
no importance as regards those tuning forks the number
of whose vibrations exceeds a hundred per second, for in
such a case these are given an amplitude of a few millimeters
only; but it would be of importance with regard to instruments
whose number of vibrations is very small, and to
which it might be desirable to give great amplitude; for
then, as I have long ago shown, the duration of the oscillation
would depend a little on the amplitude, but a very
little, it is true.

I shall not refer now to the applications of these instruments
in chronography, but will rather point out first the
applications in which they are destined to produce an effective
power.

For this purpose it is necessary to make them pretty massive.
The number of the vibrations depends upon such massiveness,
and it is necessity to know the relation which exists
between these two quantities in order to be able to construct
an instrument under determinate conditions. I made in
former years such a research with regard to tuning forks of
prismatic form, that is to say, of a constant rectangular section
continuing even into the bent portion where the parallel
branches are united by a semicylinder, at the middle of
which is the wrought iron rod as well as the branches. The
thickness of the instrument is the dimension parallel to the
vibrations; its width is the dimension which is perpendicular
to them, and its length is reckoned from the extremity
of the branches up to the middle of the curved portion.

It is found that the number of vibrations is independent
of the width, proportional to the thickness, and very nearly
inverse ratio of the square of the length, provided the
latter exceeds ten centimeters.

If we represent the length by l, the thickness by e, and the
number of vibrations by n, we shall have the following
formula:

n = k × (e / l²)

in which k is a constant quantity whose value depends upon
the nature of the metal of which the tuning fork is made.

This constant varies very little from steel to malleable
cast iron, and it may be taken as equal to 818270.

Thus, then, we have a means of constructing a tuning fork
in which two of the three quantities, n, e, l, are given in
advance. Experience proves that no errors are committed
exceeding one or two per cent.

It is seen from this that there is a means of increasing the
mass of the instrument without changing anything in the
thickness, the length or, consequently, the number of vibrations,
and this is by increasing the breadth.

It is in this way that I have succeeded in having long massive
tuning forks made of malleable iron, giving no more
than 12 to 15 vibrations per second, and vibrating with perfect
regularity. Fig. 2, annexed, shows one of these instruments
of about 55 centimeters length, whose breadth, E, is
from 5 to 6 centimeters, and which makes about fifteen
double vibrations per second only.

FIG. 2.—THE ELECTRICAL TUNING FORK.

This number might be still further reduced, but at the
expense of our being led to exaggerate the longitudinal
dimensions of the apparatus in such a way as to make it inconvenient.
The object may be attained more simply by
loading the branches with slides supporting leaden weights,
M, of 500 grammes each. By fixing these slides at different
points on the branches, the number of vibrations can be
made to vary from simple to double, and even triple. Thus,
by fixing them at the extremity of the branches the number
of the vibrations is reduced to 5 or 6.

There will be seen in the figure the electro-magnet which
keeps up the vibration. This is formed of three simple
electro-magnets, whose bobbins have a resistance of no more
than 10 ohms, and which are united in series. The interrupting
plate, P, against which the style, s, rests at each
vibration, is capable of a forward movement, or one of
recoil, by the aid of a screw, V, and of an eccentric movement
which is produced by a small handle, m, and during
which its plane remains invariable. This arrangement permits
the point of contact of the style and plate to be varied
without changing the precision with which the contact
takes place, and all the points of the plate to be slowly used
in succession before replacing it. The motion is produced
by means of a relatively weak pile, whose poles are connected
to the terminals, A and A’. Three Callaud elements
of triple surface, renewed one after the other every month
at the most, are sufficient to keep up the vibrations continuously,
day and night, without interruption, and that too
even when the instrument is employed in producing a small
mechanical power, as we shall see further on.

We have now seen how electro-tuning forks may be constructed
of large dimensions, of large mass, and giving a
small number of vibrations per second.

Such instruments are well fitted to perform the role of
electrical interrupters, and it was in such a character that
one of them figured in the Exhibition of the Upper School
of Telegraphy as a type of an interrupter for testing piles.

FIG. 3.—ARRANGEMENT FOR TESTING ELECTRIC PILES.

When it is desired to test a pile to ascertain the practicability
of employing it in telegraphy, it is necessary to make
it perform a work which shall be as nearly as possible identical
with that which it will be called on to do, until it is
used up, to estimate the duration of such work, to measure
regularly the constants of the pile, the electro-motive power,
and the internal resistance. Usually, in telegraphy, this
work consists in sending over a line of a certain resistance
intermittent currents, through the intermedium of suitable
manipulators. It suffices then to cause the branches of the
electro tuning fork to play the role of one of these manipulators.
For doing this the tuning fork carries two insulating
ebonite or ivory strips, B B (Fig. 3), which, at every
oscillation, abut against vertical brass springs, r. Each of
these latter is located in front of the platinized point of a
screw, v, which is affixed to a small metallic tongue. The
springs and tongues are insulated from each other, and are
mounted on a piece which may be moved by a screw, V, so
as to cause the springs of the strips, B B’, to approach or
recede according to the amplitude of the instrument’s vibrations.
Each spring and tongue is connected with terminals
affixed to the base of the apparatus. One of the poles of
one element, P, of the pile is connected with the tongue and
corresponding screw, while the other pole is connected with
the screw in front of it through the intermedium of a galvanometer,
g², which gives the intensity of the intermittent
current, and of a resistance coil, b², which performs the
role of an artificial telegraph line. The apparatus being set
in operation, it will be seen that the current from the pile is
emitted once at every vibration.

Thus there may be exhausted as many pile elements as
there are springs, and that, too, simultaneously; and the contacts
of the screws and springs can be regulated in such a
way that the duration of the emissions shall be the same for
all.

At the laboratory of the School of Telegraphy one of
these instruments has operated without interruption, day
and night, during eighteen months.

FIG. 4.—VERY RAPID ELECTRIC TUNING FORK.

The apparatus shown in Fig. 4 is also an interrupting
electro-tuning fork, but it makes a much greater number of
vibrations than the preceding, and may serve for other
electric tests.

The operation of the tuning fork is kept up electrically by
the aid of the screw, v, and the corresponding plate; of the
style, s, and of the fine wire spiral spring, f, both insulated
from the fork, from the electro-magnet, N, and from the
two wires, F F’, which communicate with a pile.

The interrupting system is symmetrical with the first. It
consists of the style, s, of the spiral spring, f, of the screw,
v, and of the plate that this carries at its extremity. The
terminal, B, which carries the spring, f, and the rod which
carries the screw being insulated from each other, it is only
necessary to cause to terminate therein the extremities of a
circuit comprising one pile, in order to produce in the circuit
a number of interruptions equal to that of the tuning
fork’s vibrations. Provided the lengths of the springs,
f and f’, are proper, such vibrations will not be altered.

Moreover, the instrument is so arranged as to produce
vibrations whose duration can be varied at pleasure and kept
constant during the whole time the experiments last. This
is done by modifying the amplitude of the vibrations; for
the greater the amplitude, the longer likewise the duration
of the contact of the style, s, on the corresponding plate,
and the shorter the duration of the interruption. In order
to modify the amplitude, the action of the electro-magnet
on the branches of the apparatus is made to vary. To effect
this, the electro-magnet is made movable perpendicularly by
the aid of a screw, V, between two slides, so that the core,
N, may be moved with respect to the median line of the
branches, and even be raised above them. Its action diminishes,
necessarily, while it is being raised, and the amplitude
of the vibrations likewise diminishes gradually and continuously.
It may thus be made, without difficulty, to vary
from two to three tenths of a millimeter to three or four
millimeters or more.

But it is not sufficient to cause the amplitude to vary; it is
necessary to measure it and to keep it constant at the value
desired.

FIG. 5.

The measurement is effected by the aid of a very simple
apparatus that I have before described under the name of
the vibrating micrometer. This is a small square of paper
carrving a design like that shown in Fig. 5, and which is
seen in Fig. 4 glued to one of the masses, M, which serve
to vary the number of the instrument’s vibrations. This
figure is in fact, an angle, one of whose sides is graduated
into millimeters, for example, and the other forms the edge
of a wide black band. The apex of the angle is above and
the divided side is perpendicular to the direction of the
vibrations.

Under such conditions, when the fork is vibrating, the
apex of the angle, by virtue of the persistence of impressions
upon the retina, seems to advance along the graduation in
measure as the amplitude of the vibrations increases. If an

angle has been drawn such that the slope of one of its sides
to the other is one-tenth, it is easy to see that for each millimeter
passed over apparently by the apex of the angle, the
amplitude will increase by two-tenths of a millimeter.

This is the way, then, that the amplitude is measured.
On another hand, it suffices to keep the apex of the angle of
the micrometer immovable, in order to be sure of the constancy
of the tuning fork’s amplitude; and this is done,
when necessary, by causing the screw, V, to move slightly.

The instrument represented in Fig. 4 is, moreover, fixed
to a support devised by Mr. A. Duboscq, so as to make it
possible to give the tuning fork every position possible with
respect to a vertical plane; to raise it or lower it, and to
move it backward or forward so that it may be employed
for chimography, and in all those experiments in which
electro-tuning folks are used.

E. MERCADIER.

[LONGMAN’S MAGAZINE.]

OUR ORIGIN AS A SPECIES.

By Richard Owen, C.B., F.R.S.

There seems to be a manifest desire in some quarters to
anticipate the looked for and, by some, hoped-for proofs of
our descent, or rather ascent, from the ape.

In the September issue of the Fortnightly Review a writer
cites, in this relation, the “Neanderthal skull, which possesses
large bosses on the forehead, strikingly suggestive of
those which give the gorilla its peculiarly fierce appearance;”
and he proceeds: “No other human skull presents so utterly
bestial a type as the Neanderthal fragment. If one
cuts a female gorilla-skull in the same fashion, the resemblance
is truly astonishing, and we may say that the only
human feature in the skull is its size.”¹

In testing the question as between Linnæus and Cuvier of
the zoological value of the differences between lowest man
and highest ape, a naturalist would not limit his comparison
of a portion of the human skull with the corresponding one
of a female ape, but would extend it to the young or immature
gorilla, and also to the adult male; he would then find
the generic and specific characters summed up, so far, at
least, as a portion or “fragment” of the skull might show
them. What is posed as the “Neanderthal skull” is the roof
of the brain-case, or “calvarium” of the anatomist, including
the pent-house overhanging the eye-holes or “orbits.”
There is no other part of the fragment which can be supposed
to be meant by the “large bosses” of the above quotation.
And, on this assumption, I have to state that the
super-orbital ridge in the calvarium in question is but little
more prominent than in certain human skulls of both higher
and lower races, and of both the existing and cave-dwelling
periods. It is a variable cranial character, by no means indicative
of race, but rather of sex.

Limiting the comparison to that on which the writer
quoted bases his conclusions—apparently the superficial
extent of the roof plate—its greater extent as compared with
that of a gorilla equaling, probably, in weight the entire
frame of the individual from the Neanderthal cave, is
strongly significant of the superiority of size of brain in the
cave-dweller. The inner surface moreover indicates the more
complex character of the soft organ on which it was moulded;
the precious “gray substance” being multiplied by certain
convolutions which are absent in the apes. But there is
another surface which the unbiased zoologist finds it requisite
to compare. In the human “calvarium” in question,
the mid-line traced backward from the super-orbital ridge
runs along a smooth track. In the gorilla a ridge is raised
from along the major part of that tract to increase the surface
giving attachment to the biting muscles. Such ridge in
this position varies only in height in the female and the male
adult ape, as the specimens in the British Museum demonstrate.
In the Neanderthal individual, as in the rest of mankind,
the corresponding muscles do not extend their origins
to the upper surface of the cranium, but stop short at the
sides forming the inner wall or boundary of what are called
the “temples,” defined by Johnson as the “upper part of
the sides of the head,” whence our “biting muscles” are
called “temporal,” as the side-bones of the skull to which
they are attached are also the “temporal bones.” In the
superficial comparison to which Mr. Grant Allen has restricted
himself in bearing testimony on a question which
perhaps affects our fellow-creatures, in the right sense of the
term, more warmly than any other in human and comparative
anatomy, the obvious difference just pointed out ought
not to have been passed over. It was the more incumbent
on one pronouncing on the paramount problem, because the
“sagittal ridge in the gorilla,” as in the orang, relates to
and signifies the dental character which differentiates all
Quadrumana from all Bimana that have ever come under
the ken of the biologist. And this ridge much more
“strikingly suggests” the fierceness of the powerful brute-ape
than the part referred to as “large bosses.” Frontal
prominences, more truly so termed, are even better developed
in peaceful, timid, graminivorous quadrupeds than in
the skulls of man or of ape. But before noticing the evidence
which the teeth bear on the physical relations of man
to brute, I would premise that the comparison must not be
limited to a part or “fragment” of the bony frame, but to
its totality, as relating to the modes and faculties of locomotion.

Beginning with the skull—and, indeed, for present aim,
limiting myself thereto—I have found that a vertical longitudinal
section brings to light in greatest number and of
truest value the differential characters between lowest Homo
and highest Simia. Those truly and indifferently interested
in the question may not think it unworthy their time—if it
has not already been so bestowed—to give attention to the
detailed discussions and illustrations of the characters in
question in the second and third volumes of the “Transactions
of the Zoological Society.”² The concluding memoir,
relating more especially to points of approximation in cranial
and denial structure of the highest Quadrumane to the
lowest Bimane, has been separately published.

I selected from the large and instructive series of human
skulls of various races in the Museum of the Royal College
of Surgeons that which was the lowest, and might be called
most bestial, in its cranial and dental characters. It was
from an adult of that human family of which the life-characters
are chiefly but truly and suggestively defined in
the narrative of Cook’s first voyage in the Endeavor.³

Not to trespass further on the patience of my readers, I
may refer to the “Memoir on the Gorilla,” 4to, 1865. Plate
xii. gives a view, natural size, of the vertical and longitudinal

section of an Australian skull; plate xi. gives a similar
view of the skull of the gorilla. Reduced copies of these
views may be found at p. 572, figs. 395, 396, vol. ii, of my
“Anatomy of Vertebrates.”

As far as my experience has reached, there is no skull
displaying the characters of a quadrumanous species, as that
series descends from the gorilla and chimpanzee to the
baboon, which exhibits differences, osteal or dental, on
which specific and generic distinctions are founded, so
great, so marked, as are to be seen, and have been above
illustrated, in the comparison of the highest ape with the
lowest man.

The modification of man’s upper limbs for the endless
variety, nicety, and perfection of their application, in fulfillment
of the behests of his correspondingly developed
brain—actions summed up in the term “manipulation”—testify
as strongly to the same conclusion. The corresponding
degree of modification of the human lower limbs, to
which he owes his upright attitude, relieving the manual
instruments from all share in station and terrestrial locomotion—combine
and concur in raising the group so characterized
above and beyond the apes, to, at least, ordinal distinction.
The dental characters of mankind bear like testimony.
The lowest (Melanian), like the highest (Caucasian),
variety of the bimanal order differs from the quadrumanal
one in the order of appearance, and succession to the first
set of teeth, of the second or “permanent” set. The foremost
incisor and foremost molar are the earliest to appear
in that scries; the intermediate teeth are acquired sooner than
those behind the foremost molar.⁴

In the gorilla and chimpanzee, the rate or course of progress
is reversed; the second true molar, or the one behind
the first, makes its appearance before the bicuspid molars
rise in front of the first; and the third or last of the molars
behind the first comes into place before the canine tooth has
risen. This tooth, indeed, which occupies part of the interval
between the foremost incisor and foremost molar, is the
last of the permanent set of teeth to be fully developed in
the Quadrumana; especially in those which, in their order,
rank next to the Bimana. To this differential character add
the breaks in the dental series necessitated for the reception
of the crowns of the huge canines when the gorilla or chimpanzee
shuts its mouth.

But the superior value of developmental over adult anatomical
characters in such questions as the present is too well
known in the actual phase of biology to need comment.

In the article on “Primeval Man,” the author states that
the Cave-men “probably had lower foreheads, with high
bosses like the Neanderthal skull, and big canine teeth like
the Naulette jaw.”⁵

The human lower jaw so defined, from a Belgian cave,
which I have carefully examined, gives no evidence of a
canine tooth of a size indicative of one in the upper jaw
necessitating such vacancy in the lower series of teeth which
the apes present. There is no such vacancy nor any evidence
of a “big canine tooth” in that cave specimen. And, with
respect to cave specimens in general, the zoological characters
of the race of men they represent must be founded on the
rule, not on an exception, to their cranial features. Those
which I obtained from the cavern at Bruniquel, and which
are now exhibited in the Museum of Natural History, were
disinterred under circumstances more satisfactorily determining
their contemporaneity with the extinct quadrupeds
those cave-men killed and devoured than in any other spelæan
retreat which I have explored. They show neither
“lower foreheads” nor “higher bosses” than do the skulls
of existing races of mankind.

Present evidence concurs in concluding that the modes of
life and grades of thought of the men who have left evidences
of their existence at the earliest periods hitherto discovered
and determined, were such as are now observable in
“savages,” or the human races which are commonly so
called.

The industry and pains now devoted to the determination
of the physical characters of such races, to their ways of
living, their tools and weapons, and to the relations of their
dermal, osteal, and dental modifications to those of the mammals
which follow next after Bimana in the descensive series
of mammalian orders, are exemplary.

The present phase of the quest may be far from the bourn
to yield hereafter trustworthy evidence of the origin of man;
but, meanwhile, exaggerations and misstatements of acquired
grounds ought especially to be avoided.

[1]

[2]

[3]

[4]

[5]

THE ABA OR ODIKA.

By W.H. Bacheler, M.D.

Among the many luxuriant and magnificent forest trees
of equatorial West Africa, none can surpass, for general
beauty and symmetry, that which is called by the natives
the “aba.” When growing alone and undisturbed, its
conical outline and dark green foliage remind one very much
of the white maples of the northern United States, by a
distant view, but, on a nearer approach, a dissimilarity is
observed. Wherever, in ravines or near the banks of rivers,
the soil is moist the most part of the year, there the aba
chooses to grow, and during the months of June and July
the falling fruits permeate the atmosphere with a delicious
fragrance not similar to any other. This, in form, size, and
general appearance, is very much like mango apples, so that
the natives call mangoes the “white man’s aba;” but the
wild aba is not much eaten as a fruit, one or two being sufficient
for the whole season. The kernel, or seed, is the
important and useful part.

When the fallen fruit covers the ground, much as apples
do in America, the natives go in canoes to gather it, and the
number harvested will be in proportion to the industry of the
women. The aba plum is about the size of a goose’s egg,
of a flattened, ovoid shape, and, when ripe, a beautiful golden
color. It consists of three distinct parts: the rind, the pulp,
and the seed. The pulp consists of a mass extensively interwoven
with strong filaments, which apparently grow out of
the seed and are with great difficulty separated from it.
The seed, reniform in shape, is bivalved, and constitutes
about two-thirds of the bulk of the entire plum, and the inner
kernel two-thirds the bulk of the seed.

In consequence of it being such a high tree and growing
in such inconvenient places, I have been unable to procure
a specimen of the flowers.

As soon as the fruit is brought to the village, all the inhabitants
assemble with cutlasses and engage in the work of
opening the plums and removing the kernels. The former
are thrown away as useless. The seeds are evenly spread on
the top of a rack of small sticks, under which a fire is built
in the morning, and subjected to the smoke and heat of
an entire day. Toward evening the heat is greatly augmented,

and in a couple of hours the process is completed. The
kernels are now soft, and the oil oozing from them, and while
yet in this condition they are thrown into an immense
trough and throughly beaten and mashed with a pestle.

Baskets, with banana leaves spread in the inside to prevent
the escape of the product, are in readiness, and it is put into
them and pressed down. The next day these baskets are
suspended in the sun, and at night are brought into the houses
to congeal. The process is now finished. The cakes are removed
by inversion of the baskets and “bushrope” tied
around them, by which the pieces are carried. As thus prepared,
odika is highly esteemed by the natives as an article
of food, being made into a kind of thick gravy and eaten with
boiled plantains.

While at an interior mission station on the Ogowe
River, I made some experiments in soap making. With
palm oil I succeeded very well, using for an alkali the old-fashioned
lye of ashes. But I was disappointed with the odika,
though I learned some peculiar characteristics of it as a grease.
By boiling the crude odika, I was unable, as I hoped, to
separate the oleaginous from the extraneous matter, of
which it contains a large proportion, but when the above-mentioned
lye was used instead of water, the mass, instead
of saponifying, merely separated; the grease, resembling
very much in all particulars ordinary beef tallow, rising to
the top of the caldron, while the refuse was precipitated.

After clarifying this, it answers instead of oil of theobroma
very nicely, and I have used it considerably in making ointments
and suppositories with pleasing results.

Gaboon, W. Africa, Aug., 1882.—New Remedies.

CALIFORNIA CEDARS.

The incense cedar (Libocedius decurrens) is one of the
valued trees of the California coast and mountains. It is
eminently noted for great rapidity of growth, wonderful
lightness, stiffness, and extraordinary durability. A thousand
uses have sprung up and are multiplying around this
interesting cedar as its most inestimable qualities become
better known. Fortunately it is one of the most extensively
distributed trees of the Pacific—found from the coast range
north, south to San Diego, Sierra Nevada, southern Oregon,
and most of the interior mountain region from 2,000 to 4,000
feet, and it even thrives quite well at 6,600 feet altitude,
but seeming to give out at 7,000 feet, though said to extend
to 8,500 feet, which is questionable. As usual with the sylva,
flora, and fauna, this also is found lowest along the coast,
where it finds the requisite temperature and other essentials,
with combined moisture. The base and lower trunk somewhat
resembles the Western juniper (J. occidentalis). It is to
be noted in general that trees of such broad, outwardly
sweeping, or expanded bases seldom blow over, and to the
perceptive and artistic eye their significant character is one
of firmness and stability. One hundred to two hundred
feet high, six to nine feet in diameter (rarely larger) the shaft
is often clear of limbs 80 to 100 feet, and although the lower
limbs, or even dry branches, may encumber the middle portion,
pin-knots do not damage the timber. The massive
body tapers more rapidly above than redwood, and is less
eccentric than juniper, yet its general port resembles most
the best specimens of the latter. The light cinnamon bark
is thick and of shreddy-fibered texture, but so concretely
compacted as to render the surface evenly ridged by very
long, big bars of bark. These sweep obliquely down on the
long spiral twist of swift water lines. The top is conic, the
foliage is in compressed, flattened sprays, upright, thickened,
and somewhat succulent; if not a languid type, at least in
no sense rigid. It bears some resemblance to the great
Western arborvitæ (Thuja gigantea), but the tiny leaf-scales
are opposite and quite awl-pointed. The general hue of
the foliage is light yellowish green, warmly tinted, golden
and bead tipped, with tiny, oblong male catkins, as the fruit
ripens in October and November. The cones are pendulous
from the tips of twigs, oblong, and seldom over three-quarters
of an inch long, little more than one-third as thick,
and for the most part a trifle compressed. The wood is a
pale cream-tint in color—a delicate salmon shade. This
would hardly warrant the name white cedar, sometimes
applied to it, as well as the giant arborvitæ. The extreme
lightness of the lumber and its sweetness for packing boxes
will commend it for express and commercial purposes,
for posts and fencing, and especially railway ties, for
sleepers, stringers, and ground timbers of all varieties, and
for unnumbered uses, a tithe of which cannot be told in a
brief notice. Formerly these trees were cut away and
burned up, to clear the track for redwood, tamarack, and
ponderous pith-pines, etc.; now all else is superseded by this
incense cedar. Thus is seen how hasty and ill-advised
notions give place to genuine merit.

A fungus (dædalus) attacks and honeycombs it; and riddled
as it may occasionally be, still, if spike or nail finds
substance enough to hold, or sufficient solidity to resist
crushing, then, for many purposes, even such lumber is
practically as good as the soundest timber; because when
the tree dies the fungus dies, and thenceforth will absorb no
more moisture than the soundest part, and is alike imperishable,
contrary to common experience in similar cases.
This is a timber nearly as lasting as solid granite. For
ship or boat lumber, the clear stuff from sound wood is so
exceedingly light, stiff, and durable, and so plenty and available,
that few timbers excel it, unless the yellow cedar or
cyprus (Cupressus nutkaensis) is excepted, which is a little
tougher, stronger, perhaps more elastic, and equally
durable, if judged apart from thorough tests and
careful data, which, it has been remarked, the apathy
or ignorance of some governments appear to deem unworthy
their sublime attention. There are said to be in
California a thousand times more and better kinds of naval
timbers on government lands as important to preserve as the
live oaks of the South Atlantic States. It has been asserted
as probable that, after due investigation, California would
be found to possess a vast amount of the best naval timber
in the world, a hundredfold more lasting than the best now
in use, if a few woods are excepted, of which there is understood
to be no very adequate supply.

The great Washington cedar (Sequoia gigantea) is another
important California tree. The great sequoian timber belt
lies along the Sierras, upon the first exposed mountain side—moraines
of recent retiring glaciers—that face the Pacific,
from Calaveras on the north to near the head of Deer Creek
on the south—a distance of 200 miles, or a little above 38
degrees north to a little below 36 degrees; altitude 5,000 to
8,000 feet, and rarely 8,400 feet. The belt is broken by two
gaps, each 40 miles wide, caused by manifest topographical
and glacial reasons, one gap between Calaveras and Tuolumne,
the other between Fresno and King’s River; thence
the vast forest trends south, across the broad basins of
Kaweah and Tule, a distance of 70 miles, on fresh moraine
soil, ground from high mountain flanks by glaciers. The

inscriptions are scarcely marred by post glacial agents, and
the contiguous water-worn marks are often so slight in the
rock-bound streams as to be measured by a few inches.
Rarely does one of these sound and vigorous cedars fall, and
those that do will lie 800 to 1,000 years, scarcely less perishable
than the granite on which they grew. The great
sequoian ditches, dug at a blow by their fall, and the tree
tumuli, always turned up beside the deep root-bowls, remain;
but, scientists assert, not a vestige of one outside the present
forests has yet presented itself, hence the area has not been
diminished during the last 8,000 or 10,000 years, and probably
not at all in post glacial times. These colossal sequoias
rise 275, 300, and even 400 feet aloft; are 20 to 30, and in some
rare cases 40 feet in diameter, looking like vast columnar
pillars of the skies. No known trees of the world compare
with them and their kin, the redwoods, for the focused proximity
of such a marvelous amount of timber within limited
areas—as it were, the highest standard of timber-land
capacity. The stage coach passes through one; 120 children
and a piano crowd inside another; a trunk furnishes a
house for cotillon parties to dance “stout on stumps;”
a horse and rider travel within the burnt-out hollows of
others, and so on. A single tree would furnish a two-rail
fence, 20 to 30 miles long. The tree has great value for
wood and lumber.—N.W. Lumberman.

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