SCIENTIFIC AMERICAN SUPPLEMENT NO. 514

NEW YORK, NOVEMBER 7, 1885

Scientific American Supplement. Vol. XX., No. 514.

Scientific American established 1845

Scientific American Supplement, $5 a year.

Scientific American and Supplement, $7 a year.

ROMAN REMAINS AT LEICESTER, ENGLAND.

The Roman tessellated pavement in Jewry Wall Street, Leicester,
discovered in the year 1832, is well known to archaeologists; it
has also been known as difficult of access, and hardly to be seen
in a dark cellar, and, in fact, it has not been seen or visited,
except by very few persons. Some time ago the Town Council resolved
to purchase the house and premises, with the object of preserving
the pavement in situ, and of giving additional light and
better access to it, and, this purchase having been completed in
the beginning of the present year, the work of improvement began.
It was now seen that the pavement was continuous under the premises
of the adjoining house, and under the public street, and
arrangements were at once made to uncover and annex these adjoining
parts, so as to permit the whole to be seen at one view. The
pavement thus uncovered forms a floor which, if complete, would
measure 23 feet square; it lacks a part on the west side, and also
the entire south border is missing. It is a marvel of constructive
skill, of variety and beauty in form and color, and not the least
part of the marvel arises from the almost beggarly elements out of
which the designer has produced his truly harmonious effects. No
squared, artificially colored, or glazed tesseræ, such as we
see in a modern floor, are used, but little pieces, irregularly but
purposely formed of brick and stone. There are three shades of
brick—a bright red, a dull or Indian red, and a shade between
the two; slate from a neighboring quarry gives a dark bluish gray;
an oolite supplies the warmer buff; and a fine white composition
resembling limestone is used for the center points and borders. In
addition, the outside border is formed with tesseræ of rather
larger size of a sage green limestone. Speaking generally, the
design is formed by nine octagon figures, three by three,
surrounded and divided by a guilloche cable band; the interspaces
of the octagons are filled by four smaller square patterns, and the
outer octagon spaces by 12 triangles. Outside these is a border
formed by a cable band, by a second band of alternate heart-shaped,
pear-shaped, and bell-shaped flowers, and by alternate white and
gray bands; and outside all is the limestone border already
described. This border is constructed with tesseræ about
five-eighths of an inch square. The remaining tesseræ vary
from one half to one-quarter inch of irregular rhomboidal form. The
construction of the pavement is remarkable. There is a foundation
of strong concrete below; over it is a bed of pounded brick and
lime three to four inches thick, and upon this a layer of fine
white cement, in which the tesseræ are laid with their
roughest side downward. Liquid cement appears to have been poured
over the floor, filling up the interstices, after which the surface
would be rubbed down and polished.

As to the probable date and occupation of the floor, it may be
observed that the site of this pavement was near the center of the
western Roman town. It is near the Jewry Wall, that is, near the
military station and fortress. It was obviously the principal house
in the place, and as clearly, therefore, the residence of the
Præfectus, the local representative of the imperial power of
Rome. The Roman occupation of the district began with the
proprætorship of Ostorius Scapula, A.D. 50. He was succeeded
in 59 by Suetonius Paulinus, who passed through Leicester from the
Isle of Anglesea when the insurrection under Boadicea broke out. In
the service of Suetonius was Julius Agricola, who was elected
consul and governor of Britain about the year 70. He is commonly
described as a wise and good governor, who introduced the arts of
civilized life, taught the natives to build, and encouraged
education. He left Britain about the year 85, and from that time to
the decline of the Roman power is but about 300 years. We shall not
be far from the truth, therefore, if we assign this work to the
time or even to the personal influence of Agricola, 1,800 years
ago.—London Times.

Some time ago we published the fact that the Empress of Germany
had offered a prize of $1,000 and the decoration of the Order of
the Red Cross to the successful inventor of the best portable field
hospital. Wm. M. Ducker, of No. 42 Fulton St., Brooklyn, sent in a
design for competition. A few days ago Mr. Ducker received notice
that his invention had won the prize. Another instance of the
recognition of American genius abroad.

THE BARBARA UTTMANN STATUE AT ANNABERG, SAXONY.

The question whether Barbara Uttmann, of Annaberg, Saxony, was
the inventor of the art of making hand cushion lace, or only
introduced it into Annaberg, in the Saxon mountains, has not yet
been solved, notwithstanding the fact that the most rigid
examinations have been made. It is the general belief, however,
that she only introduced the art, having learned it from a
foreigner in the year 1561. The person from whom she acquired this
knowledge is said to have been a Protestant fugitive from Brabant,
who was driven from her native land by the constables of the
Inquisition, and who found a home in the Uttmann family. However,
the probability is that what the fugitive showed Barbara Uttmann
was the stitched, or embroidered, laces—points, so
called—which are still manufactured in the Netherlands at the
present time. It is very probable that the specimens shown induced
Barbara Uttmann to invent the art of making lace by means of a hand
cushion.

BARBARA UTTMANN, INVENTOR OF HAND CUSHION LACE.

Very little is known of the family of Barbara Uttmann, which was
originally from Nurnberg; but members of the same migrated to the
Saxon mountains. Barbara’s husband, Christof Uttmann, was the owner
of extensive mines at Annaberg, and was very wealthy. She died at
Annaberg, Jan. 14, 1584.

The art of making hand cushion lace was soon acquired by most of
the residents in the Saxon mountains, which is a poor country, as
the occupation of most of the inhabitants was mining, and it
frequently happened that the wages were so low, and the means of
sustaining life so expensive, that some other resource had to be
found to make life more bearable. Barbara Uttmann’s invention was
thus a blessing to the country, and her name is held in high
esteem. A monumental fountain is to be erected at Annaberg, and is
to be surmounted by a statue of the country’s benefactress, Barbara
Uttmann. The statue, modeled by Robert Henze, is to be cast in
bronze. It represents Barbara Uttmann in the costume worn at the
time of the Reformation. She points to a piece of lace, which she
has just completed, lying on the cushion, the shuttles being
visible.

Some point, Valenciennes, and Guipure laces are made on a
cushion by hand, with bobbins on which the thread is wound, the
pins for giving the desired pattern to the lace being stuck into
the cushion. A yard of hand cushion lace has been sold in England
for as much as $25,000. The annexed cut, representing the Barbara
Uttmann statue, was taken from the Illustrirte Zeitung.

A Boston paper tells of a man who built two houses side by side,
one for himself and one to sell. In the house sold he had placed a
furnace against the party wall of the cellar, and from its hot air
chamber he had constructed flues to heat his own domicile. The
owner of the other house found it very hard to keep his own house
warm, and was astounded at the amount of coal it took to render his
family comfortable, while the “other fellow” kept himself warm at
his neighbor’s expense nearly a whole winter before the trick was
discovered.

IMPROVEMENTS IN CONCRETE CONSTRUCTION.

Portland cement concrete if made with a non-porous aggregate is
impervious to moisture, and yet at the same time, if not
hydraulically compressed, will take up a sufficient quantity of
moisture from the air to prevent condensation upon the surface of
the walls. It not only resists the disintegrating influences of the
atmosphere, but becomes even harder with the lapse of time. It may
also be made in several different colors, and can be finished off
to nearly a polished surface or can be left quite rough. Walls
built of this material may be made so hard that a nail cannot be
driven into them, or they can be made sufficiently soft to become a
fixing for joinery, and, if a non-porous aggregate be used, no damp
course is required. Further than this, if land be bought upon which
there is sufficient gravel, or even clay that can be burnt, the
greatest portion of the building material may be obtained in
excavating for the cellar; and in seaside localities, if the (salt)
shingle from the beach be used, sound and dry walls will be
obtained. The use of concrete as a material for building will be
found to meet all the defects set forth by practical people, as it
may be made fire-proof, vermin-proof, and nail-proof, and in
dwellings for the poor will therefore resist the destructive
efforts of the “young barbarian.” Nothing, therefore, can be better
as a building material. The system ordinarily employed to erect
structures in concrete consists of first forming casings of wood,
between which the liquid concrete is deposited, and allowed to
become hard, or “to set.” The casings are then removed, the
cavities and other imperfections are filled in, and the wall
receives a thin facing of a finer concrete. If mouldings or other
ornament be required, they are applied to this face by the ordinary
plasterer’s methods. This system finds favor in engineering
construction, and also in very simple forms of architectural work,
but with very complicated work the waste in casings is very great.
Besides this, however, the face is found sometimes to burst off,
especially if it has been applied some time after the concrete
forming the body of the wall has set, and the method of applying
ornament is not economical.

1.-18.

A system of building in concrete has recently been invented by
Messrs. F. & J.P. West, of London, illustrations of which we
now present. To this system Messrs. West have given the name of
“Concrete Exstruction,” from the Latin “exstructio,” which they
consider to be a more appropriate word than “constructio,” as
applied to concrete building in general. In Messrs. West’s system
of building in concrete, instead of employing wood casings, between
which to deposit the concrete or beton, and removing them when the
beton has become hard, casings of concrete itself are employed.
These casings are not removed when the beton has set, but they
become a part of the wall and form a face to the work. In order to
form the casings, the concrete is moulded in the form of slabs.
Figs. 1 to 18 of our engravings show various forms of the slab,
which may be manufactured with a surface of any dimensions and of
rectangular (Fig. 1), triangular, hexagonal (Figs. 2, 14, and 15),
and indeed of any other form that will make a complete surface,
while for thickness it may be suited to the work to which it is to
be applied, that used for heavy engineering work differing from
that employed in house construction. It is found that the most
convenient height for the rectangular slab (Fig. 1) is 12 inches
and the breadth 18 inches, as the parts of a structure built with
slabs of these dimensions more often correspond with architectural
measurements. The hexagonal slab (Fig. 2) is made to measure 12
inches between its parallel sides. Where combinations of these
slabs will not coincide with given dimensions, portions of slabs
are moulded to supply the deficiency. The moulds in which the slabs
are made are simple frames with linings having a thin face of
India-rubber or other suitable material, by the use of which slabs
with their edges as shown, and also of the greatest accuracy, can
be manufactured. That portion of the back of the slab which is
undercut is formed by means of soft India-rubber cores. The moulds
for making portions of the slabs have a contrivance by which their
length may be adjusted to suit given dimensions.

During the process of casting the slabs, and while they are in a
plastic state, mouldings (if required) or other ornaments, having a
suitable key, are inserted in the plastic surface, which is
finished off to them (Figs. 7, 8, and 10). The slabs may also be
cast with ornaments, etc., complete at one operation (Fig. 11), but
it is more economical to have separate moulds for the mouldings and
other ornaments, and separate moulds for the slabs, and to apply
the mouldings, etc., during the process of casting the slab.
Corbels (Fig. 9), sets off (which would be somewhat similar to the
plinth course slab No. 10), and other constructive features may
also be applied in a similar way, or may be provided for during the
casting of the slab. A thin facing of marble or other ornamental
solid or even plastic material may be applied to the face of the
slabs during the process of casting, thus enabling the work to be
finished as it is carried up, or a key may be formed on the face of
the slab to enable the structure to be plastered afterward.

FIG. 19. FIG 20.

In Fig. 20, the structure from the bottom of the trenches is
shown with the sides of the trenches removed. It will be seen that
the footings are constructed in the most economical manner by not
being stepped. As no damp-course is required in concrete work, when
the aggregate is of a non-porous material, one is not shown. Upon
the top of the footings is generally laid a horizontal slab, called
the wall-base slab, the special feature of which is that it enables
the thickness of the wall to be gauged accurately, and also
provides a fixing for the first course of slabs. Figs. 4 and 5 show
such slabs for internal and external angles, and Fig. 6 shows one
for straight work. The use of a wall-base slab is not essential,
although it is the more accurate method of building, for in cases
where it is desirable to economize labor, or from other causes, the
slabs forming the first course may be made with a thicker base, and
may be fixed by a deposition of concrete, which is allowed to set
behind them. The second course of slabs is laid upon the first
course with breaking joints of half-slab bond, each course being
keyed to the other by means of a quick-setting cementing material
poured into the key-holes provided in the edges of the slab for
that purpose, a bituminous cement being preferred. The key-holes
are made in several ways, those shown in the illustrations being of
a dovetail shape; circular, square, or indeed holes of any other
shape formed in the edges of the slab and in an oblique direction
are also employed. Special slabs for cants, or squint-quoins (Figs.
17 and 18) and angles (Figs. 12, 13, 14, 15, and 16) are
manufactured, the angle occurring (if we omit the hexagonals and
take the 18 inch slab) at three-quarters the length of each slab.
This gives a half-slab bond to each course, as on one face of the
quoin in one course will appear a quarter slab and in the course
above a three-quarter slab superimposed upon it, or vice
versa. Thus are the walls in Figs. 19 and 20 built up. For
openings, the jambs and lintels (and in window-openings the sill)
are made solid with a provision for a key-hole to the mass of
concrete filling behind them. That portion of the jambs against
which the slabs butt has a groove coinciding with a similar one in
the edge of the slab, for the purpose of forming a joggle joint by
squeezing the bedding material into them or by joggling them in
with a cement grout. All the slabs are joggled together in a
similar way.

FIG. 21.-FIG 25.

The plastic concrete filling or beton which the shells are made
to contain may be deposited between the slabs when any number of
courses (according to convenience) have been built up, and when set
practically forms with the solid work introduced a monolith, to
which the face slabs are securely keyed. With over-clayed Portland
cements, which are known to contract in setting, and with those
over-limed cements which expand (both of which are not true
Portland cements), the filling in is done in equal sections, with a
vertical space equal to each section left between them until the
first sections have become thoroughly hard, and these are then
filled in at a second operation. In order to provide for flues,
air-passages, and ways for electric installations, and for gas and
water, pipes (made of an insulating material if required) or cores
of the required shape are inserted in the plastic beton, and where
necessary suitable openings are provided on the face of the work.
Provision is also made for fixing joinery by inserting, where
required, slabs made or partly made of a material into which nails
may be driven, such as concrete made with an aggregate of burnt
clay, coke, and such like. Hollow lintels are also made of the
slabs keyed together at their vertical joints, and when in position
these are filled in with beton. This system, however, is only
recommended for fire-place openings instead of arches.

In Fig. 25, circular construction is exhibited as applied to the
apsidal end of a church, slabs similar to those shown in Fig. 21
being employed for that purpose, while Figs. 22, 23, and 24 show
forms of slabs suitable for constructing cylinders with horizontal
axes and domes. In Fig. 19, which is the upper part of Fig. 20, is
shown a system of constructing floors of these slabs. It is only
necessary to explain that the slabs are first keyed to the lower
flange of the iron joist by means of a cement (bituminous
preferred), and the combination is then fixed in position, the
edges of the slabs adhering to, or rather supported by, the iron
joist being rebated so as to receive and support intervening slabs,
the heading joints of which are laid to break with those of the
slabs supported by the joists. For double floors the iron joists
are made with a double flange on their lower edge, and are fitted
to iron girders, which cross in the opposite direction. This
provision secures the covering of the cross girders on their
undersides by the ceiling slabs. The concrete having been deposited
upon the slabs, its upper surface may be finished off in any of the
usual ways, while the ceiling may be treated in any of the ways
described for the walls. This system does not exclude the ordinary
methods of constructing floors and roofs, although it supplies a
fireproof system. Where required, bricks, stone, and, in fact, any
other building material, may be used in conjunction with the
slabs.

The system of building construction is intended, as in the case
with all concrete, to supersede brickwork and masonry in the
various uses to which they have been applied, and, at the same
time, to offer a more perfect system of building in concrete.
Hitherto slab concrete work has never been erected in a perfectly
finished state (i.e., with mouldings, etc., complete), but has
either been left in a rough state or without ornament, or else has
been constructed so as never to be capable of receiving good
ornamental treatment. Hitherto the great difficulty in constructing
concrete walls of concrete and other slabs has been to prevent the
slabs from being forced outward or from toppling over by the
pressure of the plastic filling-in material from the time of its
deposition between the slabs until it has become hard enough to
form, with the slabs, a solid wall. Besides the system of forming
the slabs of L (vertical or horizontal) section, or with a kind of
internal buttress and shoring them up from the outside, or of
supporting the slabs upon framing fixed against the faces of the
wall, several devices have been used to obviate this
difficulty.

In the first place, temporary ties, or gauges, connecting the
slabs forming the two faces of the wall, have been used, and as
soon as the plastic filling-in material has set or become hard (but
not before), these have been removed. Secondly, permanent ties or
cramps have been used, and, as their name implies, have been
allowed to remain in the wall and to be entirely buried in the
plastic filling-in material. These permanent transverse ties or
cramps have been of two kinds: those which were affixed as soon as
the slabs were placed in position, and those which were made to
form part of the manufactured slab, as, for instance, slabs of Z or
H horizontal section. Thirdly, a small layer of the plastic
filling-in material itself has been made to act as a transverse tie
by depositing it, when plastic, between the slabs forming the two
parallel faces of each course, allowing it (before filling in the
remaining part) to set and to thus connect together the slabs
forming each face of the wall, a suitable hold on the slabs, in
some cases, being given to the tie by a portion of the slab being
undercut in some way, as by being dovetailed, etc. As the slabs in
this latter system generally have wide bases, they may also be
bedded or jointed in cement, and, provided temporary ties be placed
across their upper edges to connect the slabs forming each face of
the wall together, the space between the faces of the wall may then
be filled in with the plastic concrete.

All these devices, however, are not of permanent utility; they
are only temporarily required (i.e., up to the time that the beton
has become hard and formed a permanent traverse tie between the two
faces of the wall), for it is manifest that the ultimate object of
all slab concrete construction is: (a) To retain and to mould the
plastic concrete used in forming the wall; (b) to key or fix the
slabs to the mass which they themselves have moulded; and (c) to
form a facing to the wall. When these objects shall have been
accomplished, there is no further need of any tie whatever beyond
that which naturally obtains in a concrete wall. In West’s system,
however, where the slabs are keyed course to course, any kind of
transverse tie to be used during the process of construction,
except that used in the starting course, is entirely dispensed
with, and the courses of slabs above depend solely upon the courses
of slabs below them for their stability and rigidity up to the time
that the plastic filling-in has been deposited and become hard
between both faces of the wall.

CONCRETE CONSTRUCTION

There is, however, a more decided difference between West’s
system and those previously in use, for it is marked by the fact
that the slabs composing the shell of the whole structure in many
cases may be built up before the filling-in is deposited between
the slabs, and in none of the other cases can this be done. In
fact, only in the first two cases before mentioned can more than
one course of slabs be laid before filling-in of some kind must be
done. Compared with the ordinary method of building in concrete,
this system avoids: 1. The charge for use and waste of wood
casings; 2. finishing the face of the work (both inside and
outside) after the structure is raised, and, therefore, the
bursting-off of the finished face; and 3. the difficulties
encountered in working mouldings and other ornaments on the face of
the work by the ordinary plasterer’s methods. It also provides a
face of any of the usual colors that may be obtained in concrete,
besides a facing of any other material, such as marble, etc., and
produces better and more durable work, at the same time showing a
saving in cost, especially in the better classes of work; all of
which is effected with less plant than ordinarily required. For
engineering work, such as sea walls, the hexagonal slabs, made of
greater thickness than those employed for ordinary walling, will
answer admirably, especially if the grooves be made proportionately
larger. By the use of these slabs the work may be built up with
great rapidity. For small domestic work, such as the dwellings of
artisans, these slabs; which are of such a form as to render them
easy of transport, may be supplied to the workmen themselves in
order that they may erect their own dwellings, as, on account of
the simplicity of this system and the absence of need of plant, any
intelligent mechanic can do the work.

Any arrangement of independent scaffolding may be employed for
this system, but that invented specially for the purpose by Mr.
Frank West, as shown in Fig. 26 of our engravings, is to be
preferred. It not only supplies the necessary scaffold, but also
the necessary arrangements for hoisting the slabs, as well as for
raising the liquid concrete and depositing it behind the slabs. It
is really an independent scaffold, and may be used wherever a light
tramway of contractor’s rails can be laid, which in crowded
thoroughfares would of necessity be upon a staging erected over the
footway. The under frame is carried upon two bogie frames running
upon the contractor’s rail, by which means it is enabled to turn
sharp curves, a guide plate inside the inner rail being provided at
the curves for this purpose. The scaffold itself consists of a
climbing platform made to travel up or down by means of four posts
which have racks attached to their faces, and which are fixed to
the under frame and securely braced to resist racking strains. A
worm gearing, actuated by a wheel on the upper side of the
scaffold, causes the scaffold to ascend or descend. A railgrip,
made to act at the curves as well as on the straight portions of
the rail by being attached to a radial arm fixed to the under
frame, assists the stability of the scaffold where required, but
the gauge of the rails is altered to render the scaffold more or
less stable according to its height. Combined with the same
machine, and traveling up and down one of the same posts used for
the scaffold, is an improved crane. Its action depends upon the
proposition in geometry that if the length of the base of a
triangle be altered, its angles, and therefore its altitude, are
altered. A portion of the vertical post up and down which the crane
climbs forms the base of a triangle, and a portion of the jib,
together with the stay, forms the remaining two sides. Hence, by
causing the foot of one or the other to travel upward, by means of
the worm gearing, the upper end of the jib is either elevated or
depressed.

The concrete elevator, which is also combined with the scaffold,
consists of a series of buckets carried upon two parallel endless
chains passing over two pairs of wheels. On the under frame is
fixed a hopper, into which is thrown, either by hand or from a
concrete mixer running upon the rails, the material to be hoisted,
and from which it gravitates into a narrow channel, through which
pass the buckets (attached to the chain) with a shovel-like action.
The buckets, a motor being applied to one pair of wheels, thus
automatically fill themselves, and on arriving at top are made to
tip their contents, and jar themselves, automatically into a hopper
by means of a small pinion, keyed to the shaft by which they are
attached to the endless chain, becoming engaged in a small rack
fixed for that purpose. From the upper hopper the material is taken
away to the required destination by means of a worm working in a
tube. For varying heights, extra lengths of chain and buckets are
inserted and secured by a bolt passed through each end link, and
secured by a nut. By using this scaffold, a saving in plant,
cartage, and labor is effected. The elevator may also be used for
raising any other material besides concrete.

Such is the new system of concrete construction and scaffolding
of Messrs. West, which appears to be based on sound and reasonable
principles, and to have been thoughtfully and carefully worked out,
and which moreover gives promise of success in the future. We may
add in conclusion that specimens of the work and a model of a
scaffold are shown by Messrs. West at their stand in the Inventions
Exhibition.—Iron.

ALBANY BUILDINGS SOUTHPORT. E.W. JOHNSON,
ARCHITECT.

THE BLUE PRINT PROCESS.

R.W. JONES.

1. Cover a flat board, the size of the drawing to be copied,
with two or three thicknesses of common blanket or its
equivalent.

2. Upon this place the prepared paper, sensitive side
uppermost.

3. Press the tracing firmly and smoothly upon this paper, by
means of a plate of clear glass, laid over both and clamped to the
board.

4. Expose the whole—in a clear sunlight—from 4 to 6
minutes. In a winter’s sun, from 6 to 10 minutes. In a clear sky,
from 20 to 30 minutes.

5. Remove the prepared paper and pour clear water on it for one
or two minutes, saturating it thoroughly, and hang up to dry.

The sensitive paper may be readily prepared, the only requisite
quality in the paper itself being its ability to stand
washing.

Cover the surface evenly with the following solution, using such
a brush as is generally employed for the letter-press: 1 part
soluble citrate of iron (or citrate of iron and ammonia), 1 part
red prussiate of potash, and dissolve in 10 parts of water.

The solution must be kept carefully protected from light, and
better results are obtained by not mixing the ingredients until
immediately required. After being coated with the solution, the
paper must be laid away to dry in a dark place, and must be
shielded entirely from light until used. When dry, the paper is of
a yellow and bronze color. After exposure the surface becomes
darker, with the lines of the tracing still darker. Upon washing,
the characteristic blue tint appears, with the lines of the tracing
in vivid contrast. Excellent results have been obtained from glass
negatives by this process.—Proc. Eng. Club, Phila.

REPRODUCTION OF DRAWINGS IN BLUE LINES ON WHITE GROUND.

A.H. HAIG.

The following process for making photographic copies of drawings
in blue lines on white background was invented by H. Pellet, and is
based on the property of perchloride of iron of being converted
into protochloride on exposure to light. Prussiate of potash when
brought into contact with the perchloride of iron immediately turns
the latter blue, but it does not affect the protochloride.

A bath is first prepared consisting of ten parts perchloride of
iron, five parts oxalic or some other vegetable acid, and one
hundred parts water. Should the paper to be used not be
sufficiently sized, dextrine, gelatine, isinglass, or some similar
substance must be added to the solution. The paper is sensitized by
dipping in this solution and then dried in the dark, and may be
kept for some length of time. To take a copy of a drawing made on
cloth or transparent paper, it is laid on a sheet of the sensitive
paper, and exposed to light in a printing frame or under a sheet of
glass. The length of exposure varies with the state of the weather
from 15 to 30 seconds in summer to from 40 to 70 seconds in winter,
in full sunlight. In the shade, in clear weather, 2 to 6 minutes,
and in cloudy weather, 15 to 40 minutes may be necessary. The
printing may also be done by electric light. The print is now
immersed in a bath consisting of 15 to 18 parts of prussiate of
potash per 100 parts of water. Those parts protected from the light
by the lines of the drawing immediately turn blue, while the rest
of the paper, where the coating has been converted into
protochloride by the effects of light, will remain white. Next, the
image is freely washed in water, and then passed through a bath
consisting of 8 to 10 parts of hydrochloric acid to 100 parts of
water, for the purpose of removing protoxide of iron salt.

It is now again washed well in clean water and finally dried,
when the drawing will appear in blue on a white
background.—Proc. Eng. Club, Phila.

[PROCEEDINGS OF THE ENGINEERS’ CLUB OF PHILADELPHIA.]

RELATIVE COSTS OF FLUID AND SOLID FUELS.¹

By JAMES BEATTY, JR., Member of the Club.

During the past twenty-five years there have been numerous
efforts to introduce fluid fuels as substitutes for coal, for the
evaporation of water in boilers, metallurgical operations, and, on
a small scale, for domestic purposes.

The advantages claimed for these fuels are: Reduction in the
number of stokers, one man being able to do the work of four using
solid fuel. Reduction in weight, amounting to one-half with the
better classes. Reduction in bulk; for petroleum amounting to about
thirty-six per cent., and with the gases, depending on the amount
of compression. Ease of kindling and extinguishing fires, and of
regulation of temperature. Almost perfect combustion and
cleanliness.

Siemens used gas, distilled from coal and burnt in his well
known regenerative furnace.

Deville experimented with petroleum on two locomotives running
on the Paris and Strassburg Railroad.

Selwyn experimented with creosote in a small steam yacht, and
under the boilers of steamship Oberlin.

Holland experimented with water-gas in the furnace of a
locomotive running on the Long Island Railroad.

Isherwood experimented with petroleum under the boilers of
United States steamers.

Three railroads in Russia are using naphtha in their
locomotives, and steamers on the Volga are using the same fuel.

Wurtz experimented with crude petroleum in a reheating furnace
at Jersey City.

Dowson, Strong, Lowe, and others have devised systems for the
production of water gas.

These experiments, in general, have produced excellent results
when considered merely in the light of heat production, but, in
advocating their systems, the inventors seem to have overlooked the
all-important item of cost.

It is the object of this paper to show the impracticability of
such systems when considered from a commercial standpoint, so long
as the supply of coal lasts, and prices keep within reasonable
limits.

In many cases, authors on the subject have given purely
theoretical results, without allowing for losses in the
furnace.

The fuels to be considered are anthracite and bituminous coals,
crude petroleum, and coal, generator and water gases.

The average compositions of these fuels (considering only the
heating agents), as deduced from the analysis of eminent chemists,
are:

PERCENTAGE BY WEIGHT.

We will employ the formula of Dulong—

to compute the theoretical heating powers of these fuels. In the
case of methane, CH₄, the formula is not true, but the
error is not great enough to seriously affect the result. This
gives for the combustion of one pound of:

Reducing the above to terms of pounds of water evaporated from
212° F., we have:

POUNDS OF WATER EVAPORATED FROM 212° F.

The results of experiments show the efficiency of fluid-burning
furnaces to be about ninety per cent., while with coal sixty per
cent. may be taken as a good figure. The great difference in the
efficiencies is due to the fact that fluid fuels require for
combustion very little air above the theoretical quantity, while
with the solid fuels fully twice the theoretical quantity must be
admitted to dilute the products of combustion.

Correcting our previous results for these efficiencies, we
have:

POUNDS OF WATER ACTUALLY EVAPORATED FROM 212° F., PER POUND
OF FUEL.

These figures agree closely with the results of experiments.

We will now consider the subject of cost.

The following cities have been selected, as manufacturing
centers, termini of railroads, or fueling ports for steamers.

In the case of petroleum, as it is rarely shipped in the crude
state, an approximation is made by adding to the cost at the
nearest shipping port the freight charged on refined petroleum, and
ten per cent. to cover duties and other charges.

Owing to the difficulty of obtaining prices, in some of the
cities, there may be some errors.

In calculating the following table the specific gravity of coal
gas is taken at 0.4; generator gas at 0.44; water gas at 0.48;
petroleum, 0.8.

These figures, multiplied by the actual evaporative powers as
calculated, give:

These figures are very much against the fluid fuels, but there
may be circumstances in which the benefits to be derived from their
use will exceed the additional cost. It is difficult to make a
comparison without considering particular cases, but for
intermittent heating petroleum would probably be more economical,
though for a steady fire coal holds its own.

[1]

THE MANUFACTURE OF STEEL CASTINGS.

At the opening meeting for the winter session of the Iron and
Steel Works Managers’ Institute, held at Dudley on September 12,
Mr. R. Smith-Casson in the chair, Mr. B.F. McCallem, of Glasgow,
read a paper on “Steel Castings,” which developed an interesting
discussion upon steel casting practice. Mr. McCallem said that it
was thirty years since the first crucible steel castings were made
in Sheffield in the general way, and with one exception the method
of manufacture was pretty much the same now as at that early date.
The improvement was the employment of gas furnaces instead of the
old coke holes for melting. Important economies had resulted from
this introduction. Where before it required 3 tons of coke to melt
1 ton of steel, the same thing was now done with 35 cwt. of very
poor slack. Though it was apparently easy to make crucible steel
castings, it was not in reality easy to make a true steel, that was
to say, to make a metal that contained only the correct proportions
of carbon and silicon and manganese. The only real way to make
crucible castings of true steel was to melt the proper proportions
of cast steel scrap with the proper amounts of silicon and
manganese to produce that chemical composition which was known to
be necessary in best castings. It was in consequence of this
difficulty that many makers resorted to the addition of hematite
pigs. The Bessemer process was used much more extensively upon the
Continent than in this country in the manufacture of castings. It
seemed likely that Mr. Allen’s agitator for agitating the steel in
the ladle so as to remove the gases would be taken up largely for
open-hearth castings and open-hearth mild steel, as it had a
wonderful effect. The Wilson gas producer, working in conjunction
with the open-hearth furnace, had recently produced some extremely
wonderful results. In some large works, steel was by its aid being
melted from slack which was previously absolutely a waste product.
The method of making open-hearth steel castings might be varied
greatly. The ordinary method generally practiced in this country
was a modification of the Terre Noire process. The moulds employed
were only of secondary importance to the making of the steel
itself. Unless the mould was good, no matter how good the steel
was, the casing was spoiled. The best composition which had been
found for moulds was that of a large firm in Sheffield, but
unfortunately it was rather expensive. A good steel casting ought
to contain about 0.3 per cent. carbon and 0.3 per cent. of silicon
and from 0.6 to 1 per cent. of manganese. Such a casting, if free
from other impurities, would have a strength of between 30 and 40
tons, and on an 8 inch specimen would give an elongation of 20 per
cent. or even more. It was possible by the Terre Noire process to
produce by casting as good a piece of steel as could be made by any
amount of rolling and hammering.

The chairman said that, as they had so high an authority as Mr.
McCallem present, Staffordshire men would like to know his opinion
upon the open hearth basic system, in which they were greatly
interested.

Mr. McCallem said that he believed that the basic process would
be worked successfully in this country in the open-hearth furnace
before it would be in the converter. At the Brymbo Works, in Wales,
he had seen the basic process worked very successfully in the
open-hearth furnace; and he was recently informed by the manager
that he was producing ingots at the remarkably low sum of 65s. per
ton.

The chairman said that some samples which had been sent into
Staffordshire from Brymbo for rolling into sheets had behaved
admirably. He thought that the Patent Shaft and Axletree Company,
at Wednesbury, were at the present moment putting down an
open-hearth furnace on the basic process.

The discussion was continued with considerable vigor by Messrs.
H. Fisher (vice-president), James Rigby, J. Tibbs, M. Millard,
Walker, W. Yeomans (secretary), and others. Several of these gave
it as their experience that the best castings contained the most
blowholes, and Mr. McCallem accepted the pronouncement, with some
slight qualification.

SCIENCE IN DIMINISHING CASUALTIES AT SEA.

At the recent meeting of the British Association, Don Arturo de
Marcoartu read a paper on the above subject.

He stated that he wished to draw special attention to increasing
the safety of navigation against storms, fogs, fire, and collisions
with wrecks, icebergs, or vessels, and recommending the development
of maritime telegraphy. He urged that vessels should be supplied
with apparatus to communicate with and telegraph to each other and
to the nearest coast the weather and sea passed over by them, and
that reports given by vessels should be used as “warnings” more
extensively. He wished the mid-Atlantic stations connected by
telegraph for the same purpose.

In regard to the use of oil on rough seas, he said that Dr.
Badeley in 1857, Mr. John Shields five years ago at Peterhead and
last year at Folkestone, the Board of Trade in 1883, and a
committee on life saving appliances of the United States had made
experiments. The conclusions of the committee were that in deep
water oil had a calming effect upon a rough sea, but there was
nothing in either source of information which yet answered the
question whether or not there is in the force exerted by the wind a
point beyond which oil cannot counteract its influence in causing
the sea to break. He thought it appeared that oil had some utility
on tidal bars; on wrecks, to facilitate the operations of rescue;
on lifeboats and on lifebuoys. In regard to icebergs, he thought
the possibility of obtaining an echo from an iceberg when in
dangerous proximity to a ship should be tried. He advocated the use
of automatic sprinklers in the case of fire, the establishment of
parabolic reflectors for concentration of sound, and the further
prosecution of experiments by Professor Bell in establishing
communication between vessels some distance apart by means of
interrupted electrical currents. The improvement of navigation, he
said, meant an international code of police to improve police rules
of navigation; an international code of universal telegraphy for
navigation; an international office of meteorology and navigation
to collect the studies; experiments on the weather, on the sea, on
the casualties; and the discovery by experiment of new apparatus
and appliances to diminish maritime disaster.

He had called the attention of two governments to this matter,
and he hoped that before long there would be proposed an
international congress—such as the postal, telegraph, and
sanitary congresses, and the international convention to fix the
common meridian—by one of the maritime powers, by which would
be founded an international institution to diminish casualties at
sea. He recommended a universal system of buoys. The great losses
of life and property every year were worthy the devotion of
£300,000 by an international institution, which would be much
less than the monthly average loss in navigation.

Admiral Pim said that ships were improperly built—some
were ten times longer than their beam. There was nothing in the
world so ticklish as a ship; touch her in the waist, and down she
goes. He believed sailing ships ought not to exceed four times
their beam, and steamers certainly not more than six times. He
pointed out that a fruitful cause of accidents was the stopping of
steaming all at once in the case of impending collision, by which
the rudder lost control of the vessel. If constructors looked more
to the form of the ships, and got them to steer better, collisions
would be avoided.

The Lord Advocate said it had always occurred to him that one
great secret of collisions at sea was the present system of lights,
which made it impossible for the vessel at once to inform another
vessel what it was about. The method of signaling was very crude,
and he ventured to say that it was quite out of date when vessels
met each other at a rate of speed of 24 to 25 knots. He had, as an
amateur, tried a method which he would attempt to explain. His idea
was to fit up a lantern on deck, showing an electric light. The
instrument would be controlled by the rudder, and the commanding
officer of the vessel would be able so to turn it when the helm was
put up or down that the light would flash at some distance in front
of either bow of the vessel, and thus be a signal to a vessel
coming in an opposite direction. When the helm was amidships, the
light was shown straight ahead, and could not be moved until the
helm was shifted. The direction in which the vessel was going could
not by any possibility be mistaken, and it was plain that if the
lights from two ships crossed each other, then there was danger. If
the lights were clear of each other, then the ships would pass
safely.

Sir James Douglass asked if his Lordship had made any
experiments.

The Lord Advocate said he had not. The Board of Trade had such a
number of inventions on this subject on hand that he supposed they
were already disgusted. Besides, he was only an amateur, and left
the carrying out of the suggestion to others.

Sir James Douglass said this idea of a lantern did very well for
a short distance, but for a long distance it utterly failed. It was
very difficult to realize a movement from a distance of over a mile
out to sea, and signals were required to be visible for from two to
three miles.

The Lord Advocate said his idea depended not upon the object
light, but upon the sweep of the light on the water.

Sir James Douglass said all those questions were of the utmost
importance to a maritime country. In regard to experiments with oil
on troubled water, he had witnessed them, and he had carefully
studied all the reports, and had come to the conclusion that they
were all very well in a tub of water or a pond, but on the ocean
they were utterly hopeless. He would stake his reputation on that.
They had been tried in the neighborhood of Aberdeen, and he had
prophesied the results before they were commenced. It was utterly
hopeless to think that a quantity of oil had the power of laying a
storm—all the world could not produce oil enough to bring
about that result.

There might be something in maritime telegraphy, and he hoped
the experiments of Mr. Graham Bell, in transmitting through two or
three mile distances, would come to something. He did not believe
in powerful lights. Increase the lights to any very great extent,
and a dazzling effect was the result. In regard to sound, he
wondered that no more effective alarm was used than the whistle. It
was well known that, as the whistle instrument was enlarged, the
sound became more and more a roar. He would have ships use all
their boiler power in sounding a siren, so that the sound could be
heard at a distance of not less than two or three miles in any
weather. With such a signal as that there ought to be, not absolute
safety, but collisions would be more easily prevented. He was glad
to say that a universal system of buoys had been practically
arranged, thanks to the Duke of Edinburgh and his committee, so
that, as soon as an old system can be changed to a new one, all the
buoys would bear one universal language.

Admiral Pim pointed out that a red light would show four miles,
while a green light was only visible for two miles and a half, so
that, if a green light were seen, it indicated that the two vessels
were within two miles and a half of each other.

Sir James Douglass said there was undoubtedly a weakness in
regard to these lights; and he held that in the manufacture of
lights effect should be given to the difference that existed in the
various lights, so that, by making the green light more powerful,
it could penetrate as far as the red, and in the same way making
the red and green lights proportionately more powerful, so that
they would penetrate as far as the white light.

Sir James Douglass said he had seen a parabolic reflector for
sound tried, but, unfortunately, the reflector so intensified and
focused all the sounds about the vessel and the noise of the sea
that the operator could hear nothing but a chaos of sound.

A PLAN FOR A CARBONIZING HOUSE.

The operation of carbonizing woolen rags for the purpose of
obtaining pure wool, through the destruction of the vegetable
substances contained in the raw material, maybe divided into two
parts, viz., the immersion of the rags in acid, with subsequent
washing and drying, and the carbonization properly so called. The
first part is so well known, and is so simple in its details and
apparatus, that it is useless to dwell upon it in this place. But
the second requires more scientific arrangements than those that
seem to be generally adopted, and, as carbonization is now tending
to constitute a special industry, we think it is of interest to
give here a typical plan for a plant of this kind. It will be
remarked that this plan contains all the parts in duplicate. The
object of this arrangement is to permit of a greater production, by
rendering the operation continuous through half of the apparatus
being in operation while the other half is being emptied and
filled.

Figs. 4 and 5 give plans of the ground floor and first story,
and Figs. 1, 2, and 3 give vertical sections. The second story is
arranged like the first, and serves as a drier. As we have said,
there is a double series of chambers for carbonization, drying, and
work generally. These two series are arranged on each side of a
central portion, which contains the heating and ventilating
apparatus and a stone stairway giving access to the upper stories.
The heating apparatus is a hot air stove provided with a system of
piping. The rags to be carbonized or the wool to be dried are
placed upon wire cloth frames.

The carbonization is effected in the following way: When the
heating apparatus has been fired up, and has been operating for
about half an hour, the apertures, i, are opened so as to let the
air in, as are also those, m, which allow the hot air to pass into
the chambers. The hot air then descends from the top of the chamber
into the wool or rags, and, becoming saturated and heavier,
descends and makes its exit from the chamber through an aperture,
n, near the floor, whence it flows to the central chimney. This
latter, which is built of brick or stone, contains in its center a
second chimney (formed of cast or forged iron pipes) that serves to
carry off into the atmosphere the products of combustion from the
heating apparatus. The heat that radiates from these pipes serves
at the same time to heat the annular space through which the vapors
derived from the wool are disengaged.

The air, heated to 40° or 50°, is made to pass thus for
several hours, until the greater part of the humidity has been
removed. The temperature is then raised to 80° or 90° by
gradually closing the apertures that give access to the ventilating
chimney. In order that it may be possible to further increase the
temperature during the last hour, and raise it to 90° or
120°, an arrangement is provided that prevents all entrance of
the external air into the heating apparatus, and that replaces such
air with the hot air of the chamber; so that this hot air
circulates in the pipes of the stove and thus becomes gradually
hotter and hotter. The hot vapors that issue from the lower chamber
rise into the upper one, where they are used for the preliminary
drying of another part of the materials.

The hot air stove should be well lined with refractory clay, in
order to prevent the iron from getting red hot, and the grate
should be of relatively wide surface. All the pipes should be of
cast iron, and all the joints be well turned. Every neglect to see
to such matters, with a view to saving money, will surely lead in
the long run to bad results.

PLAN OF WORKS FOR CARBONIZING WOOL. (Scale
1-200.)

The mode of work indicated here is called the moist process. It
necessitates the use of a solution of sulphuric acid, but, as this
latter destroys most colors, it cannot be used when it is desired
to preserve the tint of the woolen under treatment. In this case
recourse is had to the dry process, which consists in substituting
the vapors of nitric acid heated to 115° or 125° for the
sulphuric acid. The arrangement of the rooms must likewise be
different. The chambers, which may be in duplicate, as in the
preceding case, are vaulted, and are about three yards long by
three wide and three high. The rags are put into wire cages that
have six divisions, and that are located in the middle of the
chamber, where they are slowly revolved by means of gearings. Under
the floor are the heating flues, and upon it is a reservoir for
holding the vessel that contains the acid to be vaporized. The
arrangements for the admission of air and carrying along the vapors
are the same as in the other case. Great precaution should be taken
to have the flues so constructed as to prevent fire.—Bull,
de la Musee de l’Industrie.

APPARATUS FOR EVAPORATING ORGANIC LIQUIDS.

According to Mr. D’A. Bernard, it is especially important, in
the dry distillation of distiller’s wash in a closed vessel, for
the production of methyls, ammonia, acetates, and methylamine, that
the mass shall be divided as completely as possible, since it then
takes but a relatively moderate heat to completely destroy the
organic coloring matter contained in the wash. The apparatus shown
in Figs. 1 and 2 is based upon this observation.

The wash enters, through the hopper, D, and the valve, z, a long
boiler, B, which is heated by the furnace, F, through the
intermedium of a waterbath, w. An agitator, E, moves the mass
slowly to the other extremity of the boiler, from whence it makes
its exit in the form of dust. To the frame, E, are fixed the
scrapers, b, and the interrupted pieces, a, in front of which are
the hinged valves, c. In the motion of the pieces, a, from right to
left, these valves free the apertures thereof and allow the wash to
pass, while in the motion from left to right the apertures are
closed and the valves push the mass to be evaporated before
them.

From any motor whatever, the frame, E, receives a double to and
fro motion in a horizontal and vertical direction, the latter of
which is produced by the rods, f, which are provided at their
lower, forked extremity with rollers, e, over which passes the
piece, d, that supports the frame, E. At their upper part the rods,
f, pass through the side of the boiler, through the intermedium of
stuffing boxes, and are connected by their upper extremities,
through a link, with levers, g, that revolve around the point, h. A
cam shaft, M, communicates a temporary, alternately rising and
descending motion to the levers, g, and the rods f. The same shaft,
M, opens and closes the valve, z, of the hopper, D, and thus
regulates the entrance of the wash into the boiler. The frame, E,
receives its horizontal to and fro motion from the rod, l, which
traverses a stuffing-box and is moved by a crank on an eccentric,
m. The material in powder derived from the evaporation of the wash
is stored at the extremity of the apparatus into a lixiviating
vessel, G, provided with a stirrer, H. The salts and other
analogous matters are dissolved, and the residuum, which
constitutes a carbonaceous mass, is forced out of the apparatus,
while the solution passes directly to the refinery, where it is
evaporated.

APPARATUS FOR THE EVAPORATION OF ORGANIC
LIQUIDS.

In manufactories where no refining is done, the crude potassa in
powder is pushed on to a prolongation of the apparatus which is
cooled by means of water, and is removed from time to time with
shovels by the workmen, so that the orifice of the boiler remains
constantly covered externally by the mass, and that the air cannot
re-enter the apparatus.

The gases disengaged during the operation pass into a cooler,
where they condense into a liquid which contains ammonia and
methylamine. The non-condensable part of the gases is burned in the
furnace of the manufactory.

IMPROVED LEVELING MACHINE.

In the American Court of the Inventions Exhibition, London, we
find a leveling machine for sheet metals exhibited by Mr. J.W.
Britton, of Cleveland, Ohio, and which we illustrate.

This apparatus is intended to supersede the cold rolling of
plates in order to take the buckle out of them. The sheets are
clamped in the jaws or grips shown, and the stretch is effected by
means of a hydraulic ram connected directly to the nearest pair of
jaws. The power is obtained by means of a pair of pumps run through
spur-gearing by the belt pulleys shown. The action of the machine
puts a strain on those parts of the plates which are not “bagged”
or buckled, and this causes the surface to extend, the slack parts
of the plate not being subject to the same stretching action. The
machine shown is designed to operate on sheet iron from No. 7 to
No. 30 gauge, and up to 36 in. wide, the limit for length being 120
in. About a dozen sheets can be operated on at once. The machine
appears to have met with considerable success in America, and has
been used for mild steel, iron, galvanized or tinned sheets,
copper, brass, and zinc. The details of this machine are given in
Figs. 1 to 8. Figs. 1 and 2 are a plan and side elevation of the
bed of the machine, showing the position of the hydraulic ram. Fig.
3 shows the bars used for holding the back jaws in position, with
the holes for adjusting to different lengths of the plates. Fig. 4
is a back view and section of the crosshead and one of the bolts
that connect the moving grip with the hydraulic ram. Fig. 5 gives a
plan and cross section of the back grip, and Fig. 6 is a back
elevation of the same, with a front view and section of the
gripping part. Fig. 7 shows the gear by which the jaws are opened
and closed.

BRITTON’S PLATE STRAIGHTENING MACHINE.

THE SCHOLAR’S COMPASSES.

Among the numerous arrangements that have been devised for
drawing circles in diagrams, sketches, etc., one of the simplest is
doubtless that which is represented in the accompanying figure, and
which is known in England as the “scholar’s compasses.” It consists
of a socket into which slides a pencil by hard friction, and to
which is hinged a tapering, pointed leg. This latter and the pencil
are held at the proper distance apart by means of a slotted strip
of metal and a binding screw. When the instrument is closed, as
shown in the figure to the left, it takes up but little space, and
may be easily carried in the pocket without the point tearing the
clothing, as the binding screw holds the leg firmly against the
pencil.

The mode of using the apparatus is so well shown in the figure
to the right that it is unnecessary to enter into any
explanation.—La Nature.

THE SCHOLAR’S COMPASSES.

THE INTEGRAPH.

In scientific researches in the domain of physics we often meet
with the following problem: Being given any function whatever, y =
f(x), to find a curve whose equation shall be

Let us take an example that touches us more closely; let us
suppose that we know an induced current, and that we can represent
it by a curve y=f(x). The question is to find the inductive
current, that is to say, the curve represented by the equation

The apparatus called an integraph, constructed by Messrs. Napoli
and Abdank-Abakanowicz, is designed for solving this problem
mechanically, by tracing the curve sought. Let us take another
example from the domain of electricity, in order to better show the
utility of the apparatus; let us suppose that we have a curve
representing the discharge of a pile or of an accumulator. The
abscisses represent the times, and the ordinates the amperes. The
question is to know at every moment the quantity of coulombs
produced by the pile. The apparatus traces a curve whose ordinates
give the number of coulombs sought. We might find a large number of
analogous applications.

THE INTEGRAPH.

The apparatus is represented in the accompanying figure. An iron
ruler, I, parallel with the axis of the X’s, is fixed upon a
drawing-board, and is provided with a longitudinal groove in its
upper surface. In this groove move two rollers, which, in the
center of the piece that connects them, carry two brass T-squares
that are parallel with each other and at right angles with the
first, or parallel with the axis of the Y’s. Between these two
rulers move two carriages, the first of which (nearest the axis of
the X’s) carries a point, A, designed to follow the contour of the
curve to be integrated, while the second, which is placed further
away, is provided at the center with a drawing-pen, A’, whose point
is guided by two equidistant wheels, R, R’, that roll over the
paper in such a way as to have their plane parallel with a given
straight line, and that have always a direction such that the
tangent of the point’s angle with the axes of the X’s is constantly
proportional to the ordinate of the primitive curve.

The carriages are rendered very movable by substituting rolling
for a sliding friction of the axes. To this effect, the extremities
of the axes of the wheels that support and guide them are made
thin, and roll over the plane surface of recesses formed for the
purpose in the lateral steel surfaces of the carriages, while the
circumference of the wheels rolls in grooves along the two
T-squares.

These latter are, on the one hand, carried by rollers that run
in the groove of the iron, I, and, on the other, by a single roller
that runs over the paper. At right angles with one of these bars is
fixed a divided ruler, through one point of which continually
passes a third ruler, whose extremity pivots upon the point, A, of
the first carriage.

When the divided ruler is placed upon the axis of the X’s, and
the point, A, of this carriage is following the contours of the
figure to be integrated, the tangent of the angle made by the
inclined ruler with the axis of the X’s will be proportional to the
ordinate of the figure. The wheels, R and R’, of the drawing-pen,
A’, of the second carriage must move parallel with this ruler. In
order to obtain such parallelism, we employ a parallelogram formed
as follows: Two gear-wheels of the same diameter are fixed upon the
ruler that ends at the point, A, of the first carriage, and their
line of centers is parallel with the latter. The second carriage
likewise carries two drums equal in diameter to those of the
toothed wheels. These are fixed, and their line of centers must
remain constantly parallel with the line of centers of the
gear-wheels, and consequently with the straight line which passes
through the point, A. This parallelism is obtained by means of a
weak steel spring, or of a silken thread passing over the four
wheels, the two first of which (the gear-wheels) hold it taut by
means of a barrel and spring placed in the center of one of
them.

The edge of the wheels, R, R’, of the second carriage prevents
the latter from giving way to the traction of the threads,
permitting it thus to move only in the direction of their
plane.

It will be seen that by this system two of the sides of the
parallelogram are capable of elongating or contracting through the
unwinding and winding of the silken thread on the drums of the two
cog wheels, which latter, gearing with each other, allow of the
escape of but the same length of the two threads.

It will be observed that in this system integration is effected
by forcing the pen to follow a certain direction, and that
consequently the curve does not depend upon the dimensions of the
different parts of the apparatus.—La Lumiere
Electrique.

APPARATUS FOR MANUFACTURING GASEOUS BEVERAGES.

The apparatus represented in the accompanying cuts is designed
for the manufacture of gaseous beverages, and is of Messrs. Boulet
& Co.’s make. Fig. 1 represents the apparatus complete, with
gasometer and bottling machine. Fig. 2 gives a vertical section of
the apparatus properly so called, including the producer, the
purifier, and the saturator, all grouped upon a cast-iron
column.

FIG. 1. APPARATUS FOR MANUFACTURING GASEOUS
BREEZES.

The producer, A, is designed to receive the sulphuric acid and
carbonate of lime. A mixer, F, revolves in the interior of this,
and effects an intimate admixture of the lime and acid without the
necessity of the former being pulverized beforehand. The carbonate
of lime (usually in the form of chalk) is introduced directly into
the producer through the aperture, K, while the acid contained in
the receptacle, B, at the side of the column and above the producer
flows put through a curved pipe in the bottom. The flow is
regulated by the valve, C. The receptacle, B, is lined with
platinum. As soon as the acid comes into contact with the
carbonate, there occurs a disengagement of carbonic acid gas, which
flows directly through the pipe, F, into the purifier at the upper
part of the column. From thence the gas passes into a third washer,
D, of glass. When thoroughly washed, it flows through the pipe, L,
into the gasometer, which is of galvanized iron, and is very
carefully balanced.

The saturator, which is the most important part of the
apparatus, comprises a pump, a feed reservoir, and a sphere. The
pump, which is of bronze, is placed at the side of the column, at
the lower part (Fig. 1). This sucks up the gas stored in the
gasometer and the water contained in the reservoir, and forces them
into the sphere. This latter is of bronze, cast in a single piece,
and the thickness of its sides prevents all danger of explosion. It
is silvered internally, and provided with a powerful rotary
agitator that favors the admixture of the water and gas.

FIG. 2.

The apparatus it rendered complete by a bottling machine, which
is placed either on a line with the apparatus or in front of it.
This machine is connected directly with the sphere by a block-tin
pipe.—Chronique Industrielle.

APPARATUS FOR MEASURING THE FORCE OF EXPLOSIVES.

Among the numerous apparatus that have been devised for
determining the power of powder, those designed for military
purposes are the ones most extensively used. Up to the present,
very few experimental apparatus have been constructed for civil
uses, although such are no less necessary than the others. Mr. D’O.
Guttman has examined the principal types of dynamometers with
respect to their use for testing explosive materials, and, after
ascertaining wherein they are defective, has devised an apparatus
in which the principle is the same as that employed by Messrs.
Montluisant and Reffye at Meudon, that is to say, one in which the
force of the powder is made to act upon a lead cylinder fixed in a
conical channel. Mr. Desortiaux objects that in this system, when
it is employed with charges for cannons, the action has already
begun when only a portion of the powder is burned. To this, Mr.
Guttman responds that his apparatus operates only with small
charges (300 grains), which practically inflame simultaneously in
every part when the igniting is done in a closed space. In order
that the force may not be made to act in one direction only, the
inventor uses two leaden cylinders. His apparatus is shown in the
accompanying Figs. 1, 2, and 3. It consists of a median piece, a,
and of two heads, b, of an external diameter of four inches. These
pieces are of tempered Bessemer steel. The two heads are four
inches in length, one inch of which is provided with a screw
thread. Each of them contains an aperture, c, 1.34 inches wide
below, 1.3 inches wide above, and 1.18 inches deep. This aperture
is followed by another and conical one, d, 1.38 inches deep, and
0.4 inch wide at its narrowest end, and finally by another one, e,
0.4 inch wide, which runs to the exterior. The median piece, a, is
4 inches long. It is provided at the two sides with nuts, between
which there is a cylindrical space, f, 1.8 inches long, designed to
receive the charge. The inflaming plug, g, is screwed into the
exact center of the median piece, a, which it enters to a depth of
one inch. Into the space that still remains free is screwed a plug,
h. The lower surface of the plug, g, contains a hollow space, 0.6
inch wide and deep. This hollow is prolonged by another one, 0.24
inch wide, and contains a valve, i, which has a play of about 0.08
inch. The three parts are connected by a key which passes into the
holes, x, and are rendered tight by copper rings, y.

When it is desired to charge the apparatus, a leaden cylinder,
1.34 inches long and 1.3 inches in diameter, is placed in one of
the heads, and the median piece is so screwed that it can be made
still tighter by a few turns. Then a steel plate, k, 1.3 inches
wide by 0.2 inch thick, is placed against the cylinder, and against
this plate again is placed a cardboard disk, 1.34 inches wide by
0.4 inch thick. This completely closes the hollow space. The steel
plates and heads are marked with the figures 1 and 2, which,
through the pressure, are impressed upon the leaden cylinders. Then
the charge of powder, weighing exactly 300 grains, is introduced,
and a new cardboard disk, a steel plate, and a leaden cylinder are
inserted, and the second head is screwed up. The apparatus is now
ready to operate. An ordinary priming is placed on the pyramid, h,
and the plug with the valve is screwed down in such a way that the
latter shall have a little play. By means of a hammer, m, a smart
blow is given the valve i, and this detonates the priming, and
causes an explosion of the charge. The gases make their exit
through the pyramid, h, and lift the valve and press it against the
plug, so that their escape is effectually prevented. In fact, the
explosion takes place without noise. A slight whistling, only,
indicates that the capsule has not missed fire, and that the
apparatus may be immediately opened, the gases having condensed in
the interior. It is well, however, to place the closed apparatus in
water, in order that the residua that have entered the threads of
the screw may become detached, and that the apparatus may be opened
easily. Although there is no danger in standing alongside the
apparatus, it is much better to spring the hammer by means of a
cord of a certain length, since the valve and especially the
pyramid gradually burn and may be thrown out. With some kinds of
powder the pyramid rapidly melts, and must be frequently
replaced.

APPARATUS FOR MEASURING THE FORCE OF EXPLOSIVES.

The two cones of lead obtained are then measured to 0.004 of an
inch by means of a gauge (Fig. 3).

The inventor has made numerous experiments with his apparatus,
and thinks it permits of determining the total force developed by
powder very perfectly.

SANDMANN’S VINEGAR APPARATUS.

For obtaining anhydrous or very concentrated vinegar directly
from pyrolignite of lime or other acetates by a single
distillation, Mr. D. Sandmann, of Charlottenburg, employs the
apparatus shown in the accompanying engraving. It consists of a
double-bottomed copper or enameled iron boiler, A, arranged for
being heated by steam, and the upper part of which is protected
against the action of the acid vapors disengaged during
distillation by a lining of refractory clay. The stone cover, B, is
provided with an aperture, b, through which the boiler is filled.
The steam pipe, k, is inclosed in a second pipe, f, provided with
radii. This tube serves as a stirrer; and is set in motion by means
of a pulley, g. The tube, c, is connected with a worm, h, and the
tube, d, which is provided with a valve, leads to the second
boiler, C. The head, D, which acts, by reason of its internal
arrangement, as a dephlegmator, is of enameled iron, and is
provided with a thermometer, f, and an aperture, p. Above the
spirals of the worm, e, are placed strips of glass, the free
intervals between which are filled in with pieces of glass,
porcelain, or any other material not attackable by acids. The
arrangement is such that the rising vapors can regularly and
without obstruction traverse these materials of wide surface. The
condensed liquid falls back into the lower part of the boiler. The
worm, e, debouches into a cooler, F, fed with water through the
cock, n.

At the bottom of the boiler, A, there is fixed a tubulure, r,
closed by a lever, s, and having a fastening device, o. This
tubulure permits of emptying the boiler into the reservoir, L.

A like arrangement is found in the boiler, C. The valves, V,
serve to introduce steam for heating into the double bottoms of the
two boilers. The water of condensation flows out through the tubes,
u. The water for cooling enters the coolers, F, J, and Z, through
the cocks, n, and flows out through the tubes, v.

The acetate, previously crushed, is placed in the boiler, A, and
the quantity of acid necessary to decompose it is added. The mass
is afterward mixed with care by means of the stirrer, and the
distillation may then proceed at once.

The vapors of acetic acid that are disengaged enter the boiler,
C, through the tube, d, and are kept hot by the steam. In the head,
D, they are separated into two portions, viz., into concentrated
acetic acid, which condenses by reason of its high boiling point,
and into steam, which distills and carries along but a very small
amount of acetic acid. This steam passes through the pipe, G, into
the worm, H, condenses, and afterward flows into the vessel, N.

APPARATUS FOR THE MANUFACTURE OF VINEGAR.

The acetic acid that accumulates in the boiler, C, must be again
vaporized and treated until it no longer gives off any steam at all
through the pipe, G. The amount of cooling water admitted into the
worm, e, that traverses the head, D, is regulated according to the
degree of concentration it is desired to give the acid. As soon as
the steam can no longer be separated in the boiler, C, and
temperature has reached 118 degrees, the anhydrous acetic acid is
distilled through the tube, g, and received in the cooler, K,
wherein it condenses. When the contents of the boiler, A, have been
distilled to dryness, the tube, d, is closed and the cock of the
tube, c, is opened. After this, steam is injected directly through
the tube, k, in order to distill the acetic acid that still remains
in the residuum, and which passes thus through the tube, e, into
the worm, h, and flows into the two-necked bottle, S.

There may be added to the boiler, C, certain materials for
purifying the acetic acid, such as permanganate of potassa or
acetate of soda, so as to obtain an absolutely pure
article.—Dingler’s Polytech. Journal.

FIELD KITCHENS.

We illustrate the field kitchens of Captain J.C. Baxter, R.E.,
in the Inventions Exhibition. Figs. 1 to 3 represent Captain
Baxter’s Telescopic Kitchen, both open for use and packed up for
traveling. These kitchens, which are on an entirely new principle,
consist of from three to five annular kettles, either circular or
elliptical, which are placed one on another, and the fire lighted
inside the central tube. The kettles are built up on the top of the
outer case in which they are carried, the central tube being placed
over the grate in the lid. A small iron stand, supporting an
ordinary pot, is placed on the top. When packed up, the annular
kettles fit or nest into each other, and into the outer case; the
iron stand packs inside the innermost kettle, and the top pot is
placed on the outer case, being secured by a strap. This form of
kitchen is intended for the use of officers, both regular and
volunteer, and for officers’ and sergeants’ messes on active
service or in camp. They are also suited for travelers, explorers,
colonists, boating, shooting, and fishing parties, and in fact for
all who may require to cook in the open air. Figs. 4 to 6 represent
the kitchen of the field service pattern with conical kettles,
while Figs. 7 and 8 represent the same pattern with elliptical
kettles. These kitchens consist of five annular vessels, either
circular or elliptical, which are placed one upon another, and the
fire lighted in the central tube or flue. A small iron stand,
supporting an ordinary pot or kettle, may be placed on the top as
in the other set. A small hole, 18 inches long, 6 inches deep, and
of the same width as the central tube of the annular kettles, may
be made for an ashpit, or the kitchen may be raised a few inches
from the ground on stones or turf. The annular vessels may be made
cylindrical or conical; in the latter case they will fit or nest
into one another, and save space when not in use. They may be made
circular or elliptical. Those intended for cavalry are provided
with straps to attach them to the saddle. This form of kitchen is
intended for the use of troops on active service, or in camp or
barracks, workhouses prisons, schools, and soup kitchens; also for
cooking food for cattle and hounds; and for all who may require to
cook and distribute quickly large quantities of food, soup, or tea,
or to heat water rapidly at a small cost. The manufacturers are M.
Adams & Son, London.—Iron.

FIG. 1.-FIG. 3. FIELD KITCHENS.

FIG. 4.-FIG. 6. FIELD KITCHENS.

FIG. 7.-FIG. 8. FIELD KITCHENS.

A NEW COP-WINDER.

In Germany extensive use is made of a cop-winding machine in
which the wooden spindle consists of a cone moved by a screw, and
the position of which is horizontal. Fig. 1 shows the primitive
type of the German apparatus, in which the cone that forms the cop
is set in motion by a horizontal screw. It is at first the greater
diameter of the cone that moves the tube, and permits the thread to
accumulate beneath the narrow extremity. But, as soon as a core of
thread has been formed, it is in contact with the entire surface of
the cone, and thus revolves with a mean velocity until it is
finished.

In the new model (Fig. 2) the arrangement is different. Here A
is the paper tube, with wooden base, to which it is freely
attached, and C is the cone that moves over the screw, D. The
thread passes into a groove which makes one revolution of the cone,
and from thence over the paper tube, where it receives the form of
a cop by reason of the transverse motion of the cone upon the
screw. This transverse motion is at first prevented by the click,
F, which falls into the teeth of the ratchet-wheel fixed behind the
cone. The shaft revolves continuously, but has, at the same time, a
to and fro motion in the direction of its axis, so as to cause the
thread to move forward constantly and form a cop. This to and fro
motion is obtained by means of a lever and a sleeve, I, the wheel,
H, of the shaft being set in motion by the pinion, J, actuated by
the transmission of the machine. As the spindle advances, a core is
formed; the click, F, is then pushed backward, and the cone is kept
in motion by the thread until the cop is finished.

A NEW COP-WINDING MACHINE.

Preference is usually given to the horizontal model; but the
system may likewise be applied to a vertical spindle, and the
arrangement in this case is simpler, as shown in Fig. 3. A rotary
motion of the shaft is useless here, as the click, F, acts in an
oblique position upon the ratchet-wheel, O, and pushes it by reason
of the to and fro motion of the screw.

[Continued from SUPPLEMENT, No. 513, page 8191.]

THE PRESERVATION OF TIMBER.²

REPORT OF THE COMMITTEE OF THE AMERICAN SOCIETY OF CIVIL
ENGINEERS ON THE PRESERVATION OF TIMBER, PRESENTED AND ACCEPTED AT
THE ANNUAL CONVENTION, JUNE 25, 1885.

BOUCHERIE, OR SULPHATE OF COPPER.

The name of Dr. Boucherie is generally applied to the
process, which he invented and extensively applied, of
preparing wood by forcing a solution longitudinally through the
pores of the wood by means of hydraulic pressure. As, however, he
also patented the use of sulphate of copper, and his name became
attached to the use of that antiseptic, it will be convenient here
to classify experiments made with that substance under this
head.

Dr. Boucherie was a distinguished French chemist, who between
1836 and 1846 made many elaborate researches and experiments upon
the preservation of timber. He tried many substances, and at first
recommended the use of pyrolignite of iron, but subsequently used
sulphate of copper, which he considered more effective.

His first experiments were conducted by vital suction, that is,
by tapping the living tree, and allowing the ascending sap to carry
up a preserving solution. This was not found to give uniform or
satisfactory results, and Dr. Boucherie then invented the process
which bears his name. This was practiced either by applying a cap
to the end of a freshly cut log, through which the solution was
allowed to flow by pressure, or by sawing a log nearly through in
the middle, raising it at the center slightly, so as to open the
joint, placing a strip of tarred rope or a rubber band just inside
the periphery of the cut log, and letting it spring back, so as to
form a tight joint by pressing upon the rope or band. An auger hole
bored diagonally into the cavity so formed then served to admit the
solution under pressure.

This process, applied with a solution of about one pound of
sulphate of copper to one hundred pounds of water, has been
extensively applied in France for many years, with satisfactory
results. It was found, however, that to be successful it must be
applied to freshly cut trees in the log only, and that this
involved so much delay, moving about, waste, and annoyance, that it
has now been abandoned. These difficulties would be still greater
in this country, and in the Northern States the process could not
be applied at all during the winter (or season for cutting down
trees), as the solution would freeze.

On this page is a list of the experiments which your committee
have been able to learn about, as having been made with sulphate of
copper in this country.

RECORD OF AMERICAN EXPERIMENTS.

SULPHATE OF COPPER, OR BOUCHERIE.

COMMENTS ON SULPHATE OF COPPER EXPERIMENTS.

The first experiment was carried out by Mr. W.W. Evans, on the
Southern Railway of Chili, in 1857, and he informs your committee
that in 1860, when he left that country, the ties were still good
and in serviceable condition.

We give herewith, in Appendix No. 16, an interesting letter from
Mr. E. Pontzen to Mr. Evans, on the subject of the Boucherie
process.

Experiments Nos. 2 to 16, inclusive, were all tried with various
modifications of the sulphate of copper process as introduced by
Mr. W. Thilmany in this country. They date back to 1870 (experiment
No. 2), when Mr. Thilmany was working and recommending the methods
of vital suction and of the Boucherie hydraulic pressure system.
After describing the foreign methods of injection with sulphate of
copper, he states in his first pamphlet (1870): “This process
resulted very satisfactorily, but it was found that the sulphate of
copper became very much diluted by the sap, and when the same
liquid was used several times, the decaying substance of the sap,
viz., the albumen, was reintroduced into the wood, and left it
nearly in its primitive condition.”

He accordingly proposed a double injection, first by muriate of
barytes, and, secondly, by sulphate of copper, forced through by
the Boucherie process, and it is presumed that the ties of 1870, in
experiment No. 2, which showed favorable results when examined in
1875, were prepared by that process.

Subsequently Mr. Thilmany changed his mode of application to the
Bethell process of injecting solutions under pressure in closed
cylinders, and probably the paving blocks for experiment No. 3 were
prepared in that way. The chemical examination of them by Mr.
Tilden, however, showed the “saturation very uneven; absorptive
power, high; block contains soluble salts of copper, removable by
washing.”

It was expected that the double solution, by forming an
insoluble compound, would prove an effective protection against the
teredo. Experiments Nos. 4, 5, 6, and 8, however, proved the
contrary to be the fact.

The process, when well done, gave moderately satisfactory
results against decay. A pavement laid in the yard of the Schlitz
Brewing Company, in Milwaukee (experiment No. 7), was sound in
1882, after some six years’ exposure. A report by Mr. J.F. Babcock,
a chemist of Boston (experiment No. 9), indicated favorable
results, and the planks in a ropewalk at Charlestown (experiment
No. 15), laid in 1879, were yet sound in 1882.

The experiments on railroad ties (Nos. 10, 11, 12, 13, 14, and
16), however, did not result satisfactorily. They seemed favorable
at first, and great things were expected of them; but late
examinations made on the Wabash Railroad, on the New York,
Pennsylvania, and Ohio, and on the Cleveland and Pittsburg
Railroad, have shown the ties to be decaying, and the results to be
unfavorable.

This applies to the sulphate of copper and barium process. Mr.
Thilmany has patented still another combination, in which he uses
sulphate of zinc and chloride of barium, which has been noticed
under the head of burnettizing.

Experiment No. 17 was tried on the Hudson River Railroad. It
consisted of 1,000 sap pine ties, which had been impregnated in the
South, by the Boucherie process, with a mixture of sulphate of iron
and sulphate of copper, under Hamar’s patent. These ties were laid
in the tunnel at New Hamburg, a trying exposure, and when examined,
in 1882, several of them were still in the track. The process,
however, was found to be so tedious that it was abandoned after a
year’s trial, and has not since been resumed.

In 1882 Mr. H. Fladd, of St. Louis, patented a method which is
the inverse of the Boucherie process (experiment No. 18). To the
cap fastened to the end of a freshly cut log he applies a suction
pump, and placing the other end into a vat, filled with the desired
solution, he sucks up the preserving fluid through the pores or sap
cells of the wood.

Quite a number of experimental ties have been prepared in this
way, with various chemical solutions, chief of which was sulphate
of copper, and there is probably no question but that the life of
the wood will be materially increased thereby.

Whether the process will prove more convenient and economical
than the original Boucherie process can only be determined by
practical application upon an extensive scale.

A considerable number of modifications and appliances for
working the Boucherie process have been patented in this country;
but none of them seems to have come into practical use, probably
because of the necessity for operating upon freshly cut logs, and
the inconvenience of such applications.

The table on this page gives a record of various experiments
with miscellaneous substances.

RECORD OF AMERICAN EXPERIMENTS—MISCELLANEOUS.

COMMENTS ON MISCELLANEOUS EXPERIMENTS.

Experiments Nos. 1, 2, and 3 relate to the Earle process, from
which great results were expected from 1839 to 1844. It consisted
in immersing timber, rope, canvas, etc., in a hot solution of one
pound of sulphate of copper and three pounds of sulphate of iron
mixed in twenty gallons of water. It was first tested on some
hemlock paving blocks on Chestnut Street, Philadelphia, and for a
time seemed to promise good results. Experiments with prepared
rope, exposed in a fungus pit, by Mr. James Archbald, Chief
Engineer of the Delaware and Hudson Canal, seemed also
favorable.

The process was, therefore, thoroughly tried at the Watervliet
Arsenal, where it was applied to some 63,000 cubic ft. of timber,
at a cost of about seven cents per cubic foot. The timber was used
for various ordnance purposes, and while it was found to have its
life extended, as would naturally be expected from the known
character of the antiseptics used, its strength was so far
impaired, and it checked and warped so badly, that the process was
abandoned in 1844.

The committee is indebted to General S.V. Benet, Chief of
Ordnance, for a full copy of the reports upon these
experiments.

Experiments Nos. 4 and 7 represent the lime process, which has
been applied to a considerable extent in France. The fact that
platforms and boxes used for mixing lime mortar seem to resist
decay has repeatedly suggested the use of lime for preserving
timber. In 1840 Mr. W.R. Huffnagle, Engineer of the Philadelphia
and Columbia Railroad, laid a portion of its track on white pine
sills, which had been soaked for three months in a vat of
lime-water as strong as could be maintained. Similar experiments
were tried on the Baltimore and Ohio in 1850. The result was not
satisfactory, as might be expected from the fact that lime is a
comparatively weak antiseptic (52.5 by atomic weight, while
creosote is 216), and from the extreme tediousness of three months’
soaking.

Experiments Nos. 5 and 8 were tried with sulphate of iron,
sometimes known as payenizing, and the particulars of the former
have been furnished by Mr. I. Hinckley, President of the
Philadelphia, Wilmington, and Baltimore Railroad, to whom your
committee is much indebted for a large mass of information on the
subject of timber preservation.

Mr. Hinckley has had longer and more varied experience on this
subject than any other person in this country. Beginning with
sulphate of copper in 1846, following with chloride of mercury in
1847, and chloride of zinc in 1852, going back to chloride of
mercury, and again to chloride of zinc, using the latter until
1865, then using creosote to protect the piles against the
teredo at Taunton Great River (experiment No. 2.
creosoting), he has had millions of feet of timber and lumber
prepared by the various processes, and has kindly placed at our
disposal many original reports in manuscript and pamphlets which
are now very rare.

Experiment No. 6 was made by Mr. Ashbel Welch, former President
of this Society, and consisted in boring hemlock track sills 6
× 12 with a 1-1/8 inch auger-hole 10 inches deep every 15
inches. These were filled with common salt and plugged up, as is
not infrequently done in ship-building, but while the life of the
timber was somewhat lengthened, it was concluded that the process
did not pay.

Salt has been experimented with numberless times. It is cheap,
but is a comparatively weak antiseptic, its atomic weight being
58.8 in the hydrogen scale, as against 135.5 for chloride of
mercury.

Experiment No. 9 is included in order to notice the well-known
and most ancient process of charring the outside of timber. In this
particular case, the fence posts after charring were dipped for
about three feet into a hot mixture of raw linseed oil and
pulverized charcoal, which probably acted by closing the sap cells
against the intrusion of moisture, which, as is well known, much
hastens decay. The posts, which had been set butt-end upward, were
mostly sound in 1879, after 24 years’ exposure.

Experiments Nos. 41, 42, 43, and 44 did not, however, result as
well, and numberless failures throughout the country attest that
charring is uncertain and disappointing in its results.

Much ingenuity has been wasted in devising and patenting
machinery for charring wood on a large scale to preserve it against
decay. The process, however, is so tedious in comparison with the
benefits which it confers, and the charred surface is so
objectionable for many uses, that nothing is to be expected from
the process upon a large commercial scale.

In 1857-58 Mr. H.K. Nichols tried sundry experiments (No. 10),
at Pottsville, Pa., upon timber which he endeavored to impregnate
with pyrolignite of iron by means of capillary action. Similar
experiments had previously been thoroughly tried in France by Dr.
Boucherie, but the result has not been found satisfactory.

In 1858 the Erie Railway purchased the right of using the
Nichols patent, and erected machinery at its Owego Bridge shop for
boring a 2 inch hole longitudinally through the center of bridge
timbers. This continued till 1870, when the works were burned, and
in rebuilding them the boring machinery was not replaced. The
longitudinal hole allowed a portion of the sap to evaporate without
checking the outside of the timber, and undoubtedly lengthened its
life. It is believed there are yet (1885) some sticks of timber in
the bridges of the road that were so prepared in 1868 or 1869.

In 1867 Mr. W.H. Smith patented a method of preserving timber,
by incasing it in vitrified earthenware pipes, and filling the
space between the timber and the pipe with a grouting of hydraulic
cement. This was applied to the railroad bridge connecting the
mainland with Galveston Island (experiment No. 12), and so well did
it seem to succeed at first that it was proposed to extend the
process to railroad trestlework, to fencing, to supports for
houses, and to telegraph poles. But after a while the earthenware
pipes were displaced and broken, the process was given up, and
Galveston bridge is now creosoted.

In 1868 Mr. S. Beer patented a process for preserving wood by
simply washing out the sap from its cells. Having ascertained that
borax is a solvent for sap, he prepared a number of specimens by
boiling them in a solution of borax. For small specimens, this
answered well, and a signboard treated in that way (experiment No.
13) was preserved a long time; but when applied to large timber,
the process was found very tedious and slow, and no headway has
been made in introducing it.

Experiment No. 14 was brought about by accident. Some years age
it was discovered that there was a strip of road in the track of
the Union Pacific Railroad, in Wyoming Territory, about ten miles
in length, where the ties do not decay at all. The Chief Engineer,
Mr. Blinkinsderfer, kindly took up a cotton wood tie in 1882, which
had been laid in 1868, and sent a, piece of it to the committee. It
is as sound and a good deal harder than when first laid, 14 years
before, while on some other parts of the road cottonwood ties
perish in two or five years.

The character of the soil where these results have been observed
is light and soapy, and Mr. E. Dickinson, Superintendent of the
Laramie Division, furnishes the following analysis:

The following remarks made by the chemists who made the analysis
may be of interest:

“The decay of wood arises from the presence in the wood of
substances which are foreign to the woody fiber, but are present in
the juices of the wood while growing, and consist of albuminous
matter, which, when beginning to decay, causes also the destruction
of the other constituents of the wood.”

“One of the means adopted to prevent the destruction of wood by
decay is by the chemical alteration of the constituents of the
sap.”

“This is brought about by impregnating the wood with some
substance which either enters into combination with the
constitutents of the sap or so alters their properties as to
prevent the setting up of decomposition.”

“The analysis of this soil shows that it contains large
quantities of the substances (sodium, potassium chloride, calcium,
and iron) most used in the different processes of preserving or
kyanizing wood. It also contains much inorganic matter, which also
acts as a preserving agent.”

Some of the ties so preserved have been transferred to other
portions of the track, and some of the soil has also been
transported to other localities, so that it is hoped that in the
discussion that may be expected to follow this report, some further
light will be thrown on the subject by an account of the results of
these experiments.

Experiments Nos. 15, 16, 17, and 18 are most instructive, and
convey a useful lesson.

In 1865 Mr. B.S. Foreman patented the application of a dry
powder for preserving wood, which was composed of certain
proportions of salt, arsenic, and corrosive sublimate. This action
was based upon an experience which he had had when, as a working
mechanic of Ellisburg, Jefferson County, N.Y., in 1838, he had
preserved a water-wheel shaft by inserting such a compound in
powder in the body of the wood, and ascertained that it was still
sound some 14 years later.

His theory of the action of his compound upon timber was briefly
this:

“That all wood before it can decay must ferment; that
fermentation cannot exist without heat and moisture; that the
chemical property or nature of his compound, when inserted dry into
wood, is to attract moisture, and this moisture, aided by
fermentation, liquefies the compound; that capillary attraction
must inevitably convey it through the sap ducts and medullary rays
to every fiber of the stick…. Were these crystallizations salt
alone, they would soon dissolve, but the arsenic and corrosive
sublimate have rendered them insoluble; hence they remain intact
while any fiber of the wood is left.”

“The antiseptic qualities of arsenic are also well known, and
have been known for centuries. Chemical analysis of the mummies
of Egypt to-day shows the presence of arsenic in large
quantities in every portion of their substance. Whatever other
ingredients may have entered into the compound that has been so
potent in preserving from decay the bodies of the old kings of
Egypt, and even the linen vestments of their tombs, arsenic was
most certainly one.”

The mode of application used by Mr. Foreman was to bore holes
two inches in diameter three-fourths of the way through sticks of
square timber, four feet apart, to fill them with the dry powder,
and to plug them up with a bung. For railroad ties he bored two
holes two inches in diameter, six inches inside of the rails, and
filled and plugged them. Fresh cut lumber and shingles were
prepared by piling layers upon each other with the dry powder
sprinkled between in the ratio of twenty pounds to the thousand
feet of lumber. This was allowed to remain at a temperature of at
least 458° F. until fermentation took place, when the lumber
was considered fully “foremanized.”

The process was first applied to the timber and lumber for a
steamboat, and in 1879 the result was reported to be favorable. It
was then applied to some ties on the Illinois Central Railroad,
where it did not succeed, and to some on the Chicago and
Northwestern, where they seem to have been lost sight of, being few
in number, so that your committee has not been able to learn the
result.

Great expectations were, however, entertained, and a conditional
sale was made to various parties of the right of using the process,
notably, it is said, to the Memphis and Charleston Railroad for
$50,000; and some ten miles of ties were prepared on that road,
when the poisonous nature of the ingredients used brought about
disaster.

Some shingles were prepared for a railroad freight house at East
St. Louis, but all the carpenters who put them on were taken very
ill, and one of them died.

The arsenic and corrosive sublimate effloresced from the ties
along the Memphis and Charleston Railroad. Cattle came and licked
them for the sake of the salt, and they died, so that the track for
ten miles was strewed with dead cattle. The farmers rose up in
arms, and made the railroad take up and burn the ties. The company
promoting foremanizing was sued and cast in heavy damages, and it
went out of business.

In 1870 Mr. A.B. Tripler patented a mixture of arsenic and salt,
and the succeeding year a specimen of wood prepared under that
patent was submitted to the Board of Public Works of Washington,
D.C., and examined by its chemist, Mr. W.C. Tilden (experiment 19).
He found the impregnation uneven, and the absorptive power high,
but he did not find any arsenic, though its use was claimed.

The Samuel process (experiment 20) consisted in the injection,
first, of a solution of sulphate of iron, and afterward of common
burnt lime. Mr. Tilden reported the wood to be brittle, and the
water used to test the absorptive power to have been filled with
threads of fungi in forty-eight hours.

The Taylor process (experiment No. 21) used a solution of
sulphide of calcium in pyroligneous acid. It was condemned by Mr.
Tilden.

The Waterbury process (experiment 22) consisted in forcing in a
solution of common salt, followed by dead oil or creosote. It was
also condemned by Mr. Tilden.

The examinations of Mr. Tilden extended to some fourteen
different processes, most of which have already been noticed in
this report, and their practical results given.

The Board of Public Works, however, laid down a considerable
amount of prepared wood pavement in Washington, all of which is
understood to have proved a dismal failure. After a good deal of
inquiry, your committee has been enabled to obtain information of
the results of three of these experiments.

The pine paving blocks upon Pennsylvania Avenue (experiment 23)
were first kiln-dried, and then immersed in a hot solution of
sulphate of iron.

The spruce blocks on E Street (experiment 24) were treated with
chloride of zinc, or, in other words, burnettized; but the mode of
application is not stated.

The pine blocks upon Sixteenth Street (experiment 25) were
treated with the residual products of petroleum distillation. It is
stated that this was the only process in which pressure was
used.

In from three and a half to four and a half years the blocks
were badly decayed, and large portions of the streets were almost
impassable, while other streets paved in the same year with
untreated woods remained in fair condition.

It has been stated to your committee that this result, which did
much toward bringing all wood preserving processes into contempt,
was chiefly owing to the very dishonest way in which the
preparation was done; that in fact there was a combination between
the officials and the contractors by which the latter were chiefly
interested “how not to do it,” and that the above results,
therefore, prove very little on the subject of wood
preservation.

Through the kindness of the United States Navy Department your
committee is enabled to give the results of a series of experiments
(Nos. 26 to 41 inclusive) which have been carried on at the
Norfolk, Va., Navy Yard, for a series of years, by Mr. P.C.
Asserson, Civil Engineer, U.S.N., to test the effect of various
substances as a protection against the Teredo navalis. It
will be noticed that the application of two coats of white zinc
paint, of two coats of red lead, of coal tar and plaster of Paris
mixed, of kerosene oil, of rosin and tallow mixed, of fish oil and
tallow mixed and put on hot, of verdigris, of carbolic acid, of
coal tar and hydraulic cement, of Davis’ patent insulating
compound, of compressed carbolized paper, of anti-fouling paint, of
the Thilmany process, and of “vulcanized fiber,” have proved
failures.

The only favorable results have been that oak piles cut in the
month of January and driven with the bark on have resisted four or
five years, or till the bark chafed or rubbed off, and that cypress
piles, well charred, have resisted for nine years.

This merely confirms the general conclusion which has been
stated under the head of creosoting, that nothing but the
impregnation with creosote, and plenty of it, is an effectual
protection against the teredo. Numberless experiments have
been tried abroad and in this country, and always with the same
result.

There are quite a number of other experiments which your
committee has learned about which are here passed in silence. The
accounts of them are vague, or the promised results of such slight
importance as not to warrant cumbering with them this already too
voluminous report.

The committee also forbears from discussing the merits of the
many patents which have been taken out for wood preservation. It
had prepared a list of them, and investigated the probable success
of many of them, but has concluded that it is better to confine
itself to the results of actual tests, and to stick to ascertained
facts.

Neither does the committee feel called upon to point out the
great importance of the subject, and the economical advantages
which will result from the artificial preparation of wood as its
price advances. They hope, however, that the members of this
Society, in discussing this report, will dwell upon this point.

We shall instead give as briefly as possible the general
conclusions which we have reached as the result of our protracted
investigation.

DECAY OF TIMBER.

Pure woody fiber is said by chemists to be composed of 52.4
parts of carbon, 41.9 parts of oxygen, and 5.7 parts of hydrogen,
and to be the same in all the different varieties. If it can be
entirely deprived of the sap and of moisture, it undergoes change
very slowly, if at all.

Decay originates with the sap. This varies from 35 to 55 per
cent. of the whole, when the tree is felled, and contains a great
many substances, such as albuminous matter, sugar, starch, resin,
etc., etc., with a large portion of water.

Woody fiber alone will not decay, but when associated with the
sap, fermentation takes place in the latter (with such energy as
may depend upon its constituent elements), which acts upon the
woody fiber, and produces decay. In order that this may take place,
it is believed that there must be a concurrence of four separate
conditions:

1st. The wood must contain the elements or germs of fermentation
when exposed to air and water.

2d. There must be water or moisture to promote the
fermentation.

3d. There must be air present to oxidize the resulting
products.

4th. The temperature must be approximately between 50° and
100° F. Below 32° F. and above 150° F., no decay
occurs.

When, therefore, wood is exposed to the weather (air, moisture,
and ordinary temperatures), fermentation and decay will take place,
unless the germs can be removed or rendered inoperative.

Experience has proved that the coagulation of the sap retards,
but does not prevent, the decay of wood permanently.³ It is
therefore necessary to poison the germs of decay which may exist,
or may subsequently enter the wood, or to prevent their intrusion,
and this is the office performed by the various antiseptics.

We need not here discuss the mooted question between chemists,
whether fermentation and decay result from slow combustion
(eremacausis) or from the presence of living organisms (bacteria,
etc.); but having in the preceding pages detailed the results of
the application of various antiseptics, we may now indicate under
what circumstances they can economically be applied.

(To be continued).

[2]

THE SPAN OF CABIN JOHN BRIDGE.

To the Editor of the Scientific American Supplement:

Your issue of 17th October contains the fifth or sixth imprint
of Mr. B. Baker’s, C.E., recent address at the British Association
of Aberdeen which has come into my hands.

In speaking of stone bridges, he alludes to the bridge over the
Adda as 500 years old. It was never more than 39 years old as
stated in the same address, and he belittles the American Cabin
John Bridge by making its span “after all only 215 ft.” As
the builder of this greatest American stone arch, I regret that on
so important and public an occasion the writer was not
accurate.

The clear span of Cabin John Bridge is 220 ft. The difference is
not great, but in the length of a bridge span it is the last foot
that counts, as in an international yacht race to be beaten by one
minute is to fail to capture the cup.

M.C. MEIGS.

Washington, D.C., Oct. 16, 1885.

THE GERMAN CORVETTE AUGUSTA.

On the 3d of June of this year, the German cruising corvette
Augusta left the island of Perrin, in the Straits of Bab el Mandeb,
for Australia; and as nothing has been heard of her since that day,
the report that she was destroyed in the typhoon on June 3 is
probably correct. The vessel left Kiel on April 28, with the crews
for the cruisers of the Australian squadron; 283 men were on board,
including the commander, Corvette Captain Von Gloeden. There is
still a possibility that the Augusta was dismasted, and is drifting
somewhere in the Indian Ocean, or has stranded on an island; but
this is not very probable, as the Augusta was not well adapted to
weather a typhoon. During her cruise of 1876 to 1878, all the upper
masts, spars, etc, had to be removed, that she might be better
adapted to weather a cyclone or like storm. If the Augusta had not
met with an accident, she would have arrived at Port Albany in
Australia by the 30th of June or beginning of July. She was due
June 17.

The Augusta was built at Armands’ ship yards at Bordeaux, and
was bought in 1864 by Prussia. She was a screw steamer with ship’s
rigging, 237½ feet long, 35½ feet beam, 16 feet
draught, and 1,543 tons burden. Her engines had 400 horse-power,
and her armament consisted of 14 pieces.

THE GERMAN CORVETTE AUGUSTA.

During the Franco-German war of 1870-71, she was commanded by
Captain Weikhmann, and captured numerous vessels on the French
coast. January 4, 1871, she captured the French brig St. Marc, in
the mouth of the Gironde; the brig was sailing from Dunkirken to
Bordeaux with flour and bread for the Third French Division. The
Augusta then captured the Pierre Adolph, loaded with wheat, which
was being carried from Havre to Bordeaux. Then the French transport
steamer Max was captured and burned. The French men of war finally
forced the Augusta to retreat into the Spanish port of Vigo, from
which she sailed Jan. 28, and arrived March 28 at Kiel, with the
captured brig St. Marc in tow.—Illustrirte
Zeitung.

IMPROVEMENT IN METAL WHEELS.

In the Inventions Exhibitions may be seen a good form of metal
wheel, the invention of Mr. H.J. Barrett, of Hull, Eng., and which
we illustrate.

FIG. 1. FIG. 2. FIG. 3.

Fig. 1 is a perspective view of the wheel, Fig. 2 a transverse
section, and Fig. 3 a longitudinal section of the boss. These
wheels are made in two classes, A and B. Our engraving illustrates
a wheel of the former class, these wheels being designed for use on
rough and uneven roads, and when very great jolting strains may be
met with, being stronger than those of class B design. The wheels
are made with mild steel spokes, which are secured by metal straps
in the recesses cut in the annular flanges on the boss, and by a
taper bolt or rivet through the tire and rim. These spokes can be
easily taken out and renewed when necessary by any unskilled person
in a few minutes. The spokes being twisted midway of their length
give greater strength to the wheel and power to resist side strains
in pulling out of deep ruts or holes, without increasing the
weight. The bosses and straps are made of malleable iron, in which
the metal bushes are secured by means of a key with a washer
screwed up on the front end. They are also fitted with steel oil
caps to the end of the bushes, which are provided with a small set
screw, so that the cap need not be taken off when it is necessary
to lubricate the wheel, as by simply taking out the set screw oil
may be poured through the hole into the cap. The set screw also
forms a fulcrum for a key, so that the cap can be taken off or put
on when required, as well as a means of preventing the cap being
lost by shaking loose on rough roads. In all hot and dry climates,
the continued shrinking of wood wheels and loosening of the tires
is a constant source of expense and inconvenience. This wheel
having a tire and rim entirely of metal does away with the
difficulty, as the expansion and contraction are equal,
consequently the tires need only be removed when worn out, and
others can be supplied, drilled complete, ready for putting on,
which can be done by any unskilled person. The wheels of class B
design are the same in principle of construction as those of class
A, but they have cast metal bosses or naves, without loose bushes,
and are suitable for general work and ordinary roads where the
strains are not so severe. The bosses or naves are readily removed
in case of breakage, and they can be fitted with steel oil caps for
lubricating.—Iron.

APPARATUS FOR THE PRODUCTION OF WATER GAS.

The apparatus shown in the accompanying engraving is designed
for the manufacture of water gas for heating purposes, and is
described in a communication, by Mr. W.A. Goodyear, to the American
Institute of Mining Engineers.

The generator, A, is lined with refractory bricks and is filled
with fuel, which may be coal, coke, or any suitable carbonaceous
material. B and B’ are two series of regenerating chambers lined
with refractory brick, and, besides, filled with refractory bricks
piled up as shown in the figure. The partitions, C and C’, are
likewise of refractory brick, and are rendered as air-proof as
possible. Apertures, D and D’, are formed alternately at the base
of one partition and the top of the adjacent one, in order to
oblige the gases that traverse the series of chambers to descend in
one of them and to rise in the following, whatever be the number of
chambers in use.

The two flues, E and E’, lead from the bottom of the two nearest
regenerator on each side to the bottom of the generator A, and
serve to bring the current of air or steam into contact with the
fuel. Valves, F and F’, placed in these flues, permit of regulating
the current in the two directions. Pipes, M and M’, provided with
valves, G and G’, put the upper part of the generator in
communication with the contiguous chambers, T and T’. Other pipes,
N and N’, with valves, H and H’, permit of the introduction of a
current of air from the outside into the chambers, T and T’. The
pipes, O and O’, and the valves, I and I’, connected with a blower,
serve for the same purpose. The pipes, P and P’, and their valves,
J and J’, lead a current of steam. The conduits, Q and Q’, and
their valves, K and K’, direct the gases toward the purifiers and
the gasometer. Finally, the pipes, R and R’, provided with valves,
L and L’, are connected with a chimney.

The generator, A, is provided at its upper part with a feed
hopper. The doors, S and S’, of the ash box close the apertures
through which the ashes are removed.

When it is desired to use the apparatus, the pipes, P, Q, and R,
are closed by means of their valves, J, K, and L, and the valve, I,
of the pipe, O, is opened. The pipes, M and N, are likewise closed,
while the flue, E, is opened. On the other side of the generator
the reverse order is followed, that is to say, the flue, E’, is
closed, the pipes, M’ and N’, are opened, the pipes, O’, P’, and
Q’, are closed, and R’ is opened.

A current of air is introduced through the pipe, O, and this
traverses the regenerators, B, enters the chamber, T, and the
generator, A, through the flue, E. As this air rises through the
mass of incandescent fuel, its oxygen combines with an atom of
carbon and forms carbonic oxide. This gas that is disengaged from
the upper part of the fuel consists chiefly of nitrogen and
carbonic oxide, mixed with volatile hydrocarburets derived from the
fuel used. This gas, through the action of the air upon the fuel,
is called “air gas,” in order to distinguish it from the “water
gas” formed in the second period of the process.

The air gas, on issuing from the generator through the pipe, M’,
in order to pass into the chamber, F’, meets in the latter a second
current of air coming in through the pipe, N’, and which burns it
and produces, in doing so, considerable heat. The strongly heated
gases resulting from the combustion traverse the regenerators, B’,
and give up to the bricks therein the greater part of their heat,
and finally make their exit, relatively cool, through the pipe, R’,
which leads them to the chimney. When the operation has been
continued for a sufficient length of time to give the refractory
bricks in the chamber, B’, next the regenerator a high temperature,
the valve, I, is closed, thus shutting off the entrance of air
through the pipe, Q. The valve, F, of the flue, E, is also closed,
and that of the pipe, M, is opened. The valves, G’, H’, L’, of the
pipes, M’, N’, R’, are closed, and that, F’, of the flue, E’, is
opened. The valve, J’, of the pipe, P’, is then opened, and a jet
of steam is introduced through the latter.

The steam becomes superheated in traversing the regenerators,
B’, and in this state enters the bottom of the generator through
the flue, E’. In passing into the incandescent fuel that fills the
generator, the steam is decomposed, and there forms carbonic oxide,
while hydrogen is liberated. The mixture of these two gases with
the hydrocarburets furnished by the fuel constitutes water gas.
This gas on making its exit from the generator through the pipe,
M’, passes through the chambers, B, and abandons therein the
greater part of its heat, and enters the pipe, R, whence it passes
through Q into the purifiers, and then into the gasometer.

As the production of water gas implies the absorption of a large
quantity of sensible heat, it is accompanied with a rapid fall of
temperature in the chambers, B’, and eventually also in the
generator, A, while at the same time the chambers, B, are but
moderately heated by the sensible heat of the current of gas
produced. When this cooling has continued so long that the
temperature in the generator, A, is no longer high enough to allow
the fuel to decompose the steam with ease, the valve, J’, of the
pipe, P’, that leads the steam is closed, as is also the valve, K,
of the pipe, Q, while the valves, L and H, of the pipes, R and N,
are opened. After this the valve, I’, is opened, and a current of
air is let in through the pipe, O’. This air, upon traversing the
chambers, B’ and T’, is raised to a high temperature through the
heat remaining in these chambers, and then enters at the bottom of
the generator, through the flue, E’. The air gas that now makes its
exit from the pipe, M, in the chamber, T, meets another current of
air coming from the pipe, N, and is thus burned. The products
resulting from such combustion pass into the chambers, B, and then
into the chimney, through the pipe, R. The temperature then rapidly
lowers in the chambers, B’, and rises no less rapidly in the
generator, A, while the chambers, B, are soon heated to the same
temperature that first existed in the chambers, B’. As soon as the
desired temperature is obtained in the generator, A, and the
chambers, B, the air is shut off by closing the valve, I’, of the
pipe, O’; the valve, F’, of the flue, E’, is also closed, the
valves, G’ and K’, of the pipes, M’ and Q’, are opened, the valves,
G, H, and L, of the pipes, M, N, and R, are closed, and the valve,
F, of the flue, E, and the valve, J, of the pipe, P, are opened. A
current of steam enters the apparatus through the pipe, P,
traverses the chambers, B, and enters the generator through the
flue, E. The gas produced makes its exit from the generator, passes
through the pipe, M’, and the chambers, T’ and B’, and the pipe, R,
and enters the gasometer through the pipe, Q’.

WATER-GAS APPARATUS.

When the chamber, B, and the generator, A, are again in so cool
a state that the fuel no longer decomposes the steam easily, the
valves are so maneuvered as to stop the entrance of the latter, and
to send a current of air into the apparatus in the same direction
that the steam had just been taking. The temperature thereupon
quickly rises in the generator, A, while, at the same time, the
combustion of the air gas produced soon reheats the chambers, B’.
The cooled products of combustion go, as before, to the chimney.
The position of the valves is then changed again so as to send a
current of steam into the apparatus in a direction contrary to that
which the air took in the last place, and the water gas obtained
again is sent to the gasometer.

As will be seen, the process is entirely continuous, each
current of air following the same direction in the apparatus (from
left to right, or right to left) that the current of steam did
which preceded it, while each current of steam follows a direction
opposite that of the current of air which preceded it.

The inventor estimates that the cost of the coal necessary for
his process will not exceed a tenth of a cent per cubic foot of
gas.

One important advantage of the apparatus is that it can be made
of any dimensions. Instead of giving the generator the limited size
and form shown in the engraving, with doors at the bottom for the
removal of the ashes by hand from time to time, it may be
constructed after the general model of the shaft of blast furnaces,
with a hearth at the base. Upon adding to the fuel a small quantity
of flux, all the mineral parts thereof can be melted into a liquid
slag, which may be carried off just like that of blast furnaces.
There is no difficulty in constructing regenerators of refractory
bricks of sufficient capacity, however large the generators be; and
a single apparatus might, if need be, convert one thousand tons of
anthracite per day into more than five million cubic feet of
gas.

LIGHTING AND VENTILATING BY GAS.⁴

By WILLIAM SUGG, of London.

Ever since the introduction of electric lighting, the public
have been assured, by those interested in the different kinds of
lamps—arc, glow or otherwise—that henceforth, by means
of such lamps, rooms are to be lighted without heat or baneful
products such as they assert attend the use of gas, lamps, or
candles. But I think it must not be implied, from what any one has
said in favor of the electric light as a means of lighting our
dwellings, that gas is unsuitable for the purpose, or that the glow
lamp is a perfect substitute for gas, or that there is a very large
difference throughout the year on the points of health,
convenience, or comfort, or that the balance in favor rests with
electric light upon all or any of these points. The fact is, the
glow lamp is only one more means (not without certain
disadvantages) of producing light added to those which already
exist, and of which the public have the choice. Now, looking to
best means of lighting rooms, and particularly the principal rooms
of a small dwelling-house, I beg to say that the arguments which
can be adduced in favor of gas lighting in preference to any other
means greatly preponderate, and that it can be substantiated that,
light for light, under the heads of convenience, health, comfort,
reliability, readiness, and cheapness, gas is superior to all.

As a scientific means for the purposes mentioned, gas is
comparatively untried. This assertion may sound somewhat
astounding; but I think it is a true one. More than that, even in
the crude and unscientific way in which it has most frequently been
used up to the present, it has been far from unsuccessful in
comparison with electricity or other means of lighting; and in the
future it will prove the best and cheapest practical means,
although, for effect, glow lamps may be used in palatial dwellings
in conjunction with it.

It must be remembered that, in laying down a system of
artificial lighting, we have to imitate, as well as we can, that
most beautiful and perfect natural light which, without our aid,
and without even a thought from us, shines regularly every day upon
all, in such an immense volume, so perfectly diffused, and in such
wonderful chemical combination, that it may safely be said that not
one atom of the whole economy of Nature is unaffected by it, and
that we and all the animal kingdom, in common with trees and
plants, derive health and vigor therefrom. This glorious natural
light leaves our best gas, electricity, oil lamp, and all our
multiplicity of candles, immeasurably behind. But although we
cannot hope to equal, in all its beneficent results, the effects of
daylight, or to perfectly replace it, we can more perfectly make
the lighting of our homes comfortable (and as little destructive to
the eyes and to the general health) by the aid of gas than by any
other means. It must also be borne in mind that, in this country at
least, we have to fulfill the conditions of artificial lighting
under frequent differences of temperature and barometric influence,
exaggerated by the manner in which our homes are built; and that
for at least nine months of the year we require heat as well as
light in our dwellings, and that for the other three months
(excepting in some few favored localities) the nights are often
chilly, even though the days may be hot. Therefore, independently
of any effect produced by the lighting arrangements, there must be
widely different effects produced in the temperature and conditions
of the air in rooms by influences entirely beyond our control.

As an example of what I mean, a short time ago I had to preside
over a meeting which was held in a large room—one of two
built exactly alike, and in communication with each other by means
of folding doors. These rooms formed part of one of the best hotels
in London—let us call it the “Magnificent.” Of course, it was
lighted by electric glow lamps, in accordance with the latest
fashion in that department of artificial lighting, viz., suspension
lamps, in which the glow lamps grew out of leaves and scrolls,
twisted and twirled in and out, very much after the pattern of our
most æsthetic gas lamps, which, of course, are in the style
of the most artistic (late eighteenth century) oil lamps, which
were in imitation of the most classic Roman lamps, which followed
the Persian, and so on back to the time of Tubal Cain, the great
arch-artificer in metals, who most likely copied in metal some
lamps he had seen in shells or flints. Both rooms were heated by
means of the good old blazing coal fire so dear to a Briton’s
heart; and they were ventilated with all due regard to the latest
state of knowledge on the subject among architects and builders. In
fact, no pains had been spared to make these rooms comfortable in
the highest acceptation of the word.

There were, some of our members remarked, no gas burners to heat
and deteriorate the atmosphere, or to blacken the ceilings; and
therefore, under the brilliant sparkle of glow lamps, the summit of
such human felicity as is expected by a body of eighteen or twenty
business men, intent on dispatching business and restoring the lost
tissue by means of a nice little dinner afterward, ought, according
to the calculations of the architect of the building, to have been
reached. I instance this case because it is a typical one, which,
under most aspects, does not materially differ from the conditions
of home life in such residences as those whose occupiers are likely
to use electric lighting. The rooms were spacious (about 20 feet by
35 feet, and about 15 feet high); and they were lighted during the
day by means of large lantern ceiling-lights, with double glass
windows. The evening in question was chilly, not to say cold.

Upon commencing our business, we all admired the comfort of the
room; but as time went on, most of the company began to complain of
a little draught on the head and back of the neck. The draught,
which at first was only a suspicion, became a certainty, and in
another hour or so, by the time our business was over,
notwithstanding a screen placed before the door, and a blazing
fire, we were delighted to make a change to the comfortable
dining-room, which communicated with the room we had just left by
means of folding doors, closed with the exception of just
sufficient space left at one end of the room to allow a waiter to
pass in and out. Very curiously, before the soup was finished, we
became aware that the candles which assisted the electric glow
lamps (merely for artistic effect) began to flare in a most
uncandlelike manner—the flames turning down, as if some one
were blowing downward on the wicks; and at the same time the
complaints of “Draughts, horrid draughts!” became general, and from
every quarter. Finding that, as the dinner went on, the discomfort
became unbearable, even although the doors were shut and screens
put before them, I gave up dining, and took to scientific
discovery. The result of a few moments’ observation induced me to
order “those gas jets,” which I saw peeping out from among the
foliage of the electroliers, to be lighted up. In two or three
minutes the flames of the candles burned upright and steadily, and
in less than ten minutes the draughts were no longer felt; in fact,
the room became really comfortable.

The reason of the change was simple. The stratum of air lying up
at the ceiling was comparatively cold. The column of heated air
from the bodies of the twenty guests, joined to the heat produced
by the movements of themselves and the waiters, together with the
steam from the viands and respiration, displaced the colder air at
the ceiling, and notably that coldest air lying against the surface
of the glass. This cold air simply dropped straight down, after the
manner of a douche, on candles and heads below. The remedy I
advised was the setting up of a current of hotter steam and air
from the gas burners, which stopped the cooling effect of the
glass, and created a stratum of heated steam and air in slow
movement all over the ceiling. The effect was a comfortable
sensation of warmth and entire absence of draught all round the
table. Later on, to avoid the possibility of overheating the room,
the gas was put out, and the electric lights left to themselves.
But before we left, the chilliness and draughts began to be again
felt.

The incident here narrated occurred at the end of the month of
April last, when we might reasonably have hoped to have tolerably
warm nights. It is therefore clear that in this instance neither
electricity nor candles could effectually replace gas for lighting
purposes. They both did the lighting, but they utterly failed to
keep the currents of air steady. I have always remarked draughts
whenever I have remained any length of time in rooms where the
electric light is used. On a warm evening the electric light and
candles would undoubtedly have kept the room cooler than gas, with
the same kind of ventilation; I do not think they would have put an
end to cold draughts. This the steam from the gas does in all
fairly built rooms.

It is a well-known fact that dry air parts with its relatively
small amount of specific heat, in an almost incredibly rapid
manner, to anything against which it impinges. Steam, on the
contrary, from its great specific heat, remains in a heated state
for a much longer time than air. It is not so suddenly reduced to a
low temperature, and in parting with its own heat it communicates a
considerable amount of warmth to those bodies with which it comes
in contact. Thus the products of the combustion of gas (which are
principally steam) serve a useful purpose in lighting, by keeping
at the ceiling level a certain stratum of heated vapor, which holds
up, as it were, the carbonic acid and exhalation from the lungs
given off by those using the room. The obvious inference,
therefore, is that if we take off these products from the level of
the ceiling, we shall take off at the same time the impure and
vitiated air. On the other hand, if we make use of a system of
artificial lighting, which does not produce any steam, then we
shall have to adopt means to keep the air at the ceiling level
warm, in order to prevent the heated impure air from descending in
comparatively rapid currents, after having parted with its heat to
the ceiling. It may very frequently be observed on chilly days that
a number of currents of cold air seem to travel about our rooms,
although there may be no crevices in the doors and windows
sufficient to account for them; and, further, that these currents
of cold air are not noticed when the curtains are drawn and the gas
is lighted. The reason is that there is generally not enough heat
at the ceiling level in a room unlighted with gas to keep these
currents steady. Hence the complaints of chilliness which we
constantly hear when electric lights are used for the illumination
of public buildings. For example, at the annual dinner of the
Institution of Civil Engineers, held at the end of April last in
the Conservatory of the Horticultural Gardens, the heat from the
five hundred guests, and from an almost equal number of waiters and
attendants, displaced the cold air from the dome of the roof, and
literally poured down on the assembly (who were in evening dress)
in a manner to compel many of them to put on overcoats. If the
Conservatory had been lighted with gas suspended below the roof,
this would not have been the case, because sufficient steam would
have been generated to stop these cold douches, and keep them up in
the roof. In fact, if electric lights are to be used in such a
building, it will be necessary to lay hot-water pipes in the roof,
to keep warm the upper as well as the lower stratum of air, and
thus steady the currents.

Having pointed out difficulties which arise under certain
conditions of the atmosphere in rooms built with care, to make them
comfortable when electric lighting is substituted for gas, I will
lay before you some few particulars relative to the condition of
small rooms of about 12 ft. by 15 ft. by 10 ft., or any ordinary
room such as may be found in the usual run of houses in this
country. The cubical contents of such a room equals 1,700 cubic
feet. If the room is heated by means of a coal fire, we shall for
the greatest part of the year have a quantity of air taken out of
it at about 2 feet from the floor by the chimney draught, varying
(according to atmospheric conditions and the state of the fire)
from 600 to 2,000 or more cubic feet. This quantity of air must,
therefore, be admitted by some means or other into the room, or the
chimney will, in ordinary parlance, “smoke;” that is, the products
of combustion, very largely diluted with fresh air, will not all
find their way up the flue with sufficient velocity to overcome the
pressure of the heavy cold air at the top of the chimney. If no
proper inlets for air are made, this supply to the fire must be
kept up from the crevices of the doors and windows. In the line of
these currents of cold air, or “draughts” as they are usually
called, it is impossible to experience any comfort—quite the
contrary; and colds, rheumatism, and many other serious maladies
are brought on through this abundant supply of fresh air in the
wrong way and place.

According to General Morin (one of the best authorities on
ventilation), 300 cubic feet of air per hour are required for every
adult person in ordinary living rooms. Peclet says 250 cubic feet
are sufficient; less than this renders the atmosphere stuffy and
unhealthy. It is generally admitted that an average adult breathes
out from 20 to 30 cubic inches of steam and vitiated air per
minute, or, as Dr. Arnott says, a quantity equal in bulk to that of
a full-sized orange. This vitiated air and steam is respired at a
temperature of 90° Fahr.; and therefore, by reason of this
heat, it immediately ascends to the ceiling, together with the heat
and carbonic acid given off from the pores of the skin. This fact,
by the bye, can be clearly demonstrated by placing a person in the
direct rays from a powerful limelight or electric lamp, and thus
projecting his shadow sharply on a smooth white surface. It will be
observed that from every hair of the head and beard, and every
fiber of his clothing, a current of heated air in rapid movement is
passing upward toward the ceiling. These currents appear as white
lines on the surface of the wall; the cause probably being that the
extreme rarefaction of the air by the heat of the body enables the
rays of light to pass through them with less refraction than
through the denser and more moist surrounding cold air. An adult
makes, on an average, about 15 respirations per minute, and
therefore he in every hour renders to the atmosphere of the room in
which he is staying from 10 to 15 cubic feet of poisonous air. This
rises to the ceiling line, if it is not prevented; and thus
vitiates from 100 to 150 cubic feet of air to the extent of 1 per
cent, in an hour. General Morin thought that air was not good which
contained more than ½ per cent, of air which had been
exhaled from the lungs; and when we consider how dangerous to
health these exhalations are, we must admit that he was right in
his view. Therefore in one hour the 15 foot by 12 foot room is
vitiated to more than 2 feet from the ceiling by one person to the
extent of ½ per cent., and it will be vitiated by two
persons to the extent of 1 per cent, in the same time.

It must be remembered here that the degree of diffusion of the
vitiated air into the lower fresh air contained in the remaining 8
feet of the height of the room depends very materially on the
difference of temperature between these upper and lower strata and
the movements of air in the room. The heavy poisonous vapors and
gases fall into and diffuse themselves among the fresh air of the
lower strata—very readily if they are nearly the same
temperature as the upper, but scarcely at all if the air at the
ceiling line is much hotter. Hence it occurs that, in warmed rooms
of such size as I have mentioned, where one or two petroleum lamps
are used for lighting them, after two or three hours of occupation
by a family of three or four persons in winter weather, the air at
the ceiling line has become so poisonous that a bird dies if
allowed to breathe it for a very short time—sometimes,
indeed, for only a few minutes. With candles, if the illumination
of the room is maintained at the same degree as in the case of
lamps, the contamination of the air is very much worse. It is
doubtless the case that poisonous germs are rapidly developed in
atmospheres which are called “stuffy;” and although, in a healthy
state of the body, we are able to breathe them without perceptible
harm, yet even then the slight headache and uneasiness we feel is a
symptom which does not suffer itself to be lightly regarded,
whenever, from some cause or other, the general condition is
weak.

The products of combustion from coal gas (which are steam and
carbonic acid mixed with an infinitesimal quantity of sulphur) are,
proportionately, far less injurious to animal life than the
products from an equal illuminating power derived from either oil
or candles. They are, however, it is certain, destructive to germ
life; and therefore, if taken off from the ceiling level, where
they always collect if allowed to do so, no possible inconvenience
or danger to health can be felt by any one in the room. But in our
endeavors to take off the foul air at the ceiling, we encounter our
first serious check in all schemes of ventilation. We draw the
elevation and section of the room, and put in our flues with pretty
little black arrows flying out of the outlets for vitiated air, and
other pretty little red arrows flying in at the inlets; but when we
see our scheme in practice, the black arrows will persist in
putting their wings where their points ought to be; in other words,
flying into instead of out of the room.

One of the best ways of finding the true course of all the hot
and cold currents in a room is to make use of a small balloon, such
as used to be employed for ascertaining the specific gravity of
gases; and, having filled it with ordinary coal gas, balance it by
weights tied on to the car till it will rest without going up or
down in a part of the room where the air can be felt to be at about
the mean temperature, and free from draught. Then leave it to
itself, to go where it will.

As soon as it arrives in a current of heated air, it will
ascend, passing along with the current, and descending or rising as
the current is either warm or cold. The effect of the cold fresh
air from windows or doors, as well as the effect of the radiant
heat from the fire, can be thus thoroughly studied. Some of our pet
theories may receive a cruel shock from this experiment; but, in
the end, the ventilation of the room will doubtless be benefited,
if we apply the information obtained. It will be discovered that
the wide-throated chimney is the cause of the little black arrows
turning their backs on the right path and our theoretical outlets
for vitiated air becoming inlets. The chimney flue must have an
enormous supply of air, and it simply draws it from the most easily
accessible places. From 1,000 to 2,000 cubic feet of air per hour
is a large “order” for a small room. Therefore, until we have made
ample provision for the air supply to the fire, it is quite useless
to attempt to ventilate the upper part of the room, either by
ventilating gas lights or one of the cheap ventilators with little
talc flappers, opening into the chimney when there is an up
draught, and shutting themselves up when there is any tendency to
down draught. The success of these and all other ventilators
depends upon there being a good supply of air from under the door
or through the spaces round the window frames. These fresh air
supplies are, of course, unendurable; but if one of the spaces
between the joists of the floor is utilized to serve as an air
conduit, and made to discharge itself under the fender (raised
about two inches for the purpose), quite another state of things
will be set up. Then the supply of air thus arranged for will
satisfy the fire, without drawing from the doors and windows, and
at the same time supply a small quantity of fresh air into the
room. But the important fact that the radiant heat from the fire
will pass through the cold air without warming it all must not be
lost sight of. In reality, radiant heat only warms the furniture
and walls of the room or whatever intercepts its rays. The air of
the room is warmed by passing over these more or less heated
surfaces; and as it is warmed, it rises away to the ceiling.
Therefore, if we desire to warm any of this fresh air supplied to
the fire, it must be made to pass over a heated surface. The fender
may be used for this purpose by filling up the two inch space along
the front, as shown in the drawing, with coarse perforated metal.
This will also prevent cinders from getting under it. It will be
found that for the greater part of the year the chimney ventilator
and the supply to the fire will materially prevent “stuffiness,”
and keep those disagreeable draughts under control, even although
the room be lighted with a 3 light chandelier burning a large
quantity of gas.

With improvements in gas burners, we may expect to light rooms
perfectly with a less expenditure of gas than we now do. But we
cannot light a room without in some measure creating heat; and I
think I have shown that we want this heat at the ceiling line for
the greater part of the year.

In summer we do not use gas for many hours; but, on the other
hand, it is more difficult, with an outside temperature at 65°
to 70° Fahr., to keep the air in proper movement in small
rooms. There are also times in the fall of the year, and also in
spring, when the nights are unusually warm; and, with a few friends
in our rooms, the lighting becomes a “hot” question, not to say a
“burning” one. On these occasions we have to resort to exceptional
ventilation, which for ordinary every-day life would be too much.
It is then, and on summer nights, that the system of ventilation by
diffusion is most useful. To explain it, when two volumes of air of
different temperatures or specific gravities find themselves on
opposite sides of a screen or other medium, of muslin, cloth, or
some more or less porous substance, they diffuse themselves through
this medium with varying rapidity, until they become of equal
density or temperature. Therefore, if we fill the upper part of a
window (which can be opened, downward) with a strained piece of
fine muslin or washed common calico, the air in the room, if hotter
than the external air, will, when the window is more or less
opened, pass out readily into the cooler air, and the cooler air
will pass in through the pores of the medium. The hotter air
passing out faster than the cooler air will come in, no draught
will be experienced; and the window may be opened very widely
without any discomfort from it.

It is, of course, quite impossible, in the limits of a paper, to
do more than indicate a means of ventilation which will be
effective under most circumstances of lighting with those gas
burners and fittings usually employed, and which will lend itself
readily to modifications which will be necessitated by the use of
some of the newest forms of burners and ventilating gas lights.

In conclusion, I wish to draw attention to an important
discovery I have made in reference to blackened ceilings, for
which, up to the present time, gas has been chiefly blamed. I have
long entertained the belief that with a proper burner it is
possible to obtain perfect combustion, without any smoke; and a
series of experiments with white porcelain plates hung over some
burners used in my own house proved conclusively that the
discoloration which spread itself all over my whitewashed ceilings
arose from the state of the atmosphere, which in all large towns is
largely mixed with heavy smoky particles, and from the dust or dirt
created in rooms by the use of coal fires as well as from the smoke
which, more frequently than one is at first supposed to imagine,
escapes from the fire-place into the room. I therefore, in two of
my best rooms, which required to have the ceilings whitened every
year, substituted varnished paper ceilings (light oak paper, simply
put on in the usual way, and varnished) instead of whitewash. I
also changed the coal fires for gas fires. These alterations have
gone through the test of two winters, and the ceilings are now as
clean as when they were first done. The burners have been used
every night, and the gas fires every day, during the two winters.
No alteration has been made in the burners employed, and no
“consumers” have been used over them. If the varnished paper
ceilings are tried, I am sure that every one will like them better
than the time honored dirty whitewash, which is simply a fine
sieve. This fact is clearly shown by the appearance of the rafters,
which, after a short time, invariably show themselves whiter than
the spaces between.

[4]

ANDERS’ TELEPHONE.

Mr. G.L. Anders’ telephone, shown in the accompanying cut,
combines in a single apparatus a transmitter, A, a receiver, B, and
a pile, C. The transmitter consists of a felt disk, a, containing
several large apertures, and fixed by an insulating ring, c, to a
metallic disk, d, situated within the box, D. The apertures, b, are
filled with powdered carbon, e, and are covered by a thin metal
plate, f, which is fixed to the insulating ring, c, by means of a
metallic washer, g. Back of the transmitter is arranged the
receiver, B, which consists of an ordinary electro-magnet with a
disk in front of its poles. The pile, C, placed behind the
receiver, consists of a piece of carbon, h, held by a partition, i,
and covered with a salt of mercury, and of a plate of zinc, l,
which is held at a distance from the mercurial salt by a spring, m,
fixed to the insulating piece, n.

ANDERS TELEPHONE

When the button, o, which is a poor conductor, is pressed, the
zinc plate, l, comes into contact with the mercurial salt, and the
circuit is closed through the line wire 1, the pile, the receiver,
the transmitter, and the line wire 2, while when the button is
freed the current no longer passes. The apparatus, then, can serve
as a receiver or transmitter only when the button is
pressed.—Bull. de la Musee de l’Industrie.

BROWN’S ELECTRIC SPEED REGULATOR.

When the sea is rough, and the screw leaves the water as a
consequence of the ship’s motions, the rotary velocity of the screw
and engine increases to a dangerous degree, because the resistance
that the screw was meeting in the water suddenly disappears. When
the screw enters the water again, the resistance makes itself
abruptly felt, and causes powerful shocks, which put both the screw
and engine in danger. Ordinary regulators are powerless to overcome
this trouble, since their construction is such that they act upon
the engine only when the excess of velocity has already been
reached.

Several remedies have been proposed for this danger. For
example, use has been made of a float placed in a channel at the
side of the screw, and which closes the moderator valve by
mechanical means or by electricity when the screw descends too low
or rises too high.

BROWN’S ELECTRIC SPEED REGULATOR.

Mr. Brown’s system is based upon a new idea. The apparatus (see
figure) consists of two contacts connected by an electric circuit.
One of them, b, is fixed to the ship in such a way as to be
constantly in the water, while the other, a, corresponds to the
position above which the screw cannot rise without taking on a
dangerous velocity. In the normal situation of the ship, the
electric circuit, c (in which circulates a current produced by a
dynamo, d), is closed through the intermedium of the water, which
establishes a connection between the two contacts. When the
contact, a, rises out of the water, the current is interrupted. The
electro, d, then frees its armature, f, and the latter is pulled
back by a spring—a motion that sets in action a small steam
engine that closes the moderator valve. When the contact, a, is
again immersed, the electro, e, attracts its armature, and thus
brings the moderator valve back to its normal position. It is clear
that the contact, a, must be insulated from the ship’s side.

Several contacts, a, might be advantageously arranged one above
another, in order to close the moderator valve more or less,
according to the extent of the screw’s rise or fall.

MAGNETO-ELECTRIC CROSSING SIGNAL.

We illustrate to-day a new application of electricity to
railroad crossing signaling which the Pennsylvania Steel Company,
of Steelton, Pa., has just perfected. By its operation an isolated
highway crossing in the woods or any lonely place can be made
perfectly safe, and that, too, without the expense of gates and a
man to work them or of a flagman. It is surely a great improvement
over the old methods, and it is likely to have a large sale. In
addition to considerations of safety, possible saving in salaries
to railroad companies by its use will be great. This device is more
reliable than a human being, and can make any crossing safe to
which it is applied. Its operation is described as follows:

FIG. 2.—MAGNETO-ELECTRIC CROSSING SIGNAL

The illustration shows the device as used on a single track
railroad, where it is so arranged as to be operated only by trains
approaching the crossing (i.e., in the form illustrated, from the
right). A similar box on the other side of the crossing is used for
trains approaching in the other direction. Two plates connected by
a link, and pivoted, are placed alongside of one rail, close enough
to it to be depressed by the treads of the wheels. By another link,
one of the plates called the rock plate (the one to the right) is
connected to a rock shaft which extends through a strong bearing
into the heavy iron case or box shown, at a suitable distance from
the rail, within which an electric generator is placed; the whole
being mounted and secured upon the ends of two long ties framed to
receive it.

The action of this rock plate is peculiar. It is pivoted at the
rear end, not to a fixed point, but to a short crank arm, the
bearing for which is inclosed in the small box shown. As the first
wheel of a train which is approaching in the desired direction
(from the right in the engraving) touches it, it will be seen that
it must not only depress it, but produce a slight forward motion,
causing a corresponding rotary motion in the rock shaft which
actuates the apparatus. On the other hand, when a train is
approaching from the other direction, or has already passed the
crossing, its wheels strike first the curved plate to the left of
the illustration, and by means of the peculiar link connections
shown, depress the rock plate so as to clear the wheels before the
wheels touch it, but the depression is directly vertical, so that
it does not give any horizontal motion to it, which would have the
effect of actuating the rock shaft. Consequently, trains pass over
the apparatus in one direction without having any effect upon it
whatever, the different point at which the same force is applied to
the rock plate giving the latter an entirely different motion.

FIG. 2.—MAGNETO-ELECTRIC CROSSING SIGNAL

The slight rotary motion which is in this way communicated to
the rock shaft, when a train is approaching in the right direction,
compresses a spring inside the case. As each wheel passes off the
rock plate, the reaction of the spring throws it up again to its
former position, giving additional speed to the gearing within,
which is set in motion at the passage of the first wheel, and
operates the electric “generator.” The spring is really the motive
power of the alarm. A small but heavy fly-wheel is connected with
the apparatus, the top of which is just visible in the engraving,
which serves to store up power to run the “generator,” which is
nothing more than a small dynamo, for the necessary number of
seconds after the rear of the train has passed. The dynamo
dispenses with all need for batteries, and reduces the work of
maintenance to occasionally refilling the oil-cups and noticing if
any part has been broken.

A suitable wire circuit is provided, commencing at the generator
with insulated and protected wire, and continued with ordinary
telegraph wire, which can be strung on telegraph poles or trees
leading to the electric gong, Fig. 2, which rings as long as the
armature revolves. It is a simple matter so to proportion the
mechanism for the required distance and speed that the revolutions
of the armature and the ringing of the gong shall continue until
the train reaches the crossing; and as each wheel acts upon the
apparatus, the more wheels there are in the train the longer the
bell will ring, a very convenient property, since the slowest
trains have nearly always the most wheels. The practical limits to
the ringing of the gong are that it will stop sounding after the
head of the train has passed the crossing and before or very soon
after the rear has passed. A “wild” engine running very slowly
might not actuate the signal as long as was desirable, but even
then it is not unreasonably claimed the warning would probably last
long enough for all practical requirements, as a team approaching a
crossing at eight miles per hour takes 42 seconds to go 500 feet.
All the bearings of any importance are self-lubricated by oil cups,
the whole apparatus being designed to require inspection not more
than once a month. The iron case when shut is water-tight, and when
duly locked cannot be maliciously tampered with without breaking
open the case; so that, the manufacturers claim, it will not be
essential to examine it more than once a month. The parts outside
the case are all strong and heavy, and not likely to get out of
order, while easily inspected.

The apparatus can be used for announcing trains as well as
sounding alarms, as the gongs can be placed upon any post or
building. The gong has a heavy striker, and makes a great deal of
noise, so that no one should fail to hear it.—Railway
Review.

THE SIZES OF BLOOD CORPUSCLES.

Professor Theodore G. Wormley, in the new edition of his work,
gives the following sizes of blood corpuscles, as measured by
himself and Professor Gulliver. We have only copied the sizes for
mammals and birds. It will be seen that, with three or four
exceptions, the sizes obtained by the two observers are practically
the same:

The subject of minute measurements was discussed in an
interesting manner in an address before the Microscopical Section
of the A.A.A.S. last year, an abstract of which was published in
this journal, vol. v., p. 181.

The slight differences in size accurately given in this table
are not always appreciable under modern amplification, but under a
power of 1,150 diameters “corpuscles differing by the 1-100000 of
an inch are readily discriminated.” For the conclusions of Prof.
Wormley as regards the possibility of identifying blood of
different animals, the reader is referred to his book on
Micro-Chemistry of Poisons.—Amer. Micro. Jour.

THE ABSORPTION OF PETROLEUM OINTMENT AND LARD BY THE SKIN.⁵

E. Joerss has investigated the question whether ointments made
with vaseline or other petroleum ointments are really as difficult
of resorption by the skin, or of yielding their medicinal
ingredients to the latter, as has been asserted. In solving this
question, he considered himself justified in drawing conclusions
from the manner in which such compounds behaved toward dead
animal membrane. If any kind of osmosis could take place, he
argued, from ointments prepared with vaseline, etc., through dead
membranes, such osmosis would most probably also take place through
living membranes. At all events, the endosmotic or exosmotic action
of the skin of a living body must necessarily play an important
role in the absorption of medicinal agents; and, on the
other hand, it is plain that fats, which render the living skin
impermeable, necessarily also diminish or entirely neutralize its
osmotic action. To test this, the author made the following
experiments:

Bladder was tied over the necks of three wide-mouthed vials,
with bottoms cut off, and each was filled with iodide of potassium
ointment.

No. 1 contained an ointment made with lard.

No. 2, one made with unguentum paraffini (Germ. Pharm.),
and

No. 3, one made with unguentum paraffini mixed with 3 per cent.
of lard.

All three vials were then suspended in beakers filled with
water. After standing twenty-four hours at the ordinary
temperature, the contents of none of the beakers gave any iodine
reaction. After having been placed into a warm temperature, between
25-37° C., all three showed iodine reactions after three hours,
Nos. 2 and 3 very strongly, No. 1 (with lard alone) very
faintly.

The same experiment was now repeated, with the precaution that
the bladder was previously washed completely free from chlorine.
Each vial was suspended, at a temperature of 25-27° C., in 50
grammes of distilled water. After three hours, the contents of No.
1 (containing the ointment made with lard) gave no
iodine reaction; the contents of the other two, however, gave
traces. After eight hours no further change had taken place. The
temperature was now raised to 30-35° C., and kept so for eight
hours. All three beakers now gave a strong iodine reaction, 0.2
c.c. of normal silver solution being required for each 15 grammes
of the contents of the beakers.

In addition to the iodide, some of the fatty base had osmosed
through the membrane in each case.

The next experiment was made by substituting a piece of the skin
(freed from chlorine by washing) of a freshly killed sheep for the
bladder. The ointment in No. 3 in this case was made with 10 per
cent. of lard. No reaction was obtained, at the ordinary
temperature, after twelve hours, nor after eight more hours, at a
temperature of 25-30° C. After letting them stand for eight
hours longer at 30-37° C., a faint reaction was obtained in the
case of the ointment made with unguentum paraffini; a still fainter
with No. 3; but no reaction at all with No. 1 (that made with
lard). None of the fats passed through by osmosis. After eight
hours more, the iodine reaction was quite decisive in all cases,
but no fat had passed through even now. On titrating 20 grammes of
the contents of each beaker,

showing that the most iodine had osmosed in the case of the
ointment made with unguentum paraffini (equivalent to
vaseline).

[5]

THE TAILS OF COMETS.

I.—If we throw a stone into the water, a wave will be
produced that will extend in a circle. The size of this wave and
the velocity with which it extends depend upon the size of the
stone, that is to say, upon the intensity of the mechanical action
that created it. The extent and depth of the water are likewise
factors.

If we cause a cord to vibrate in the water, we shall obtain a
succession of waves, the velocity and size of which will be derived
from the cord’s size and the intensity of its action. These waves,
which are visible upon the surface, constitute what I shall call
mechanical waves. But there will be created at the same time
other waves, whose velocity of propagation will be much greater
than that of the mechanical ones, and apparently independent of
mechanical intensity. These are acoustic waves. Finally,
there will doubtless be created optical waves, whose
velocity will exceed that of the acoustic ones. That is to say, if
a person fell into water from a great height, and all his senses
were sufficiently acute, he would first perceive a luminous
sensation when the first optical wave reached him, then he would
perceive the sound produced, and later still he would feel, through
a slight tremor, the mechanical wave.⁶

I

Under the action of the same mechanical energy there form, then,
in a mass of fluid, waves that vary in nature, intensity, and
velocity of propagation; and although but three modes appreciable
to our senses have been cited, it does not follow that these are
the only ones possible.

We may remark, again, that if we produce a single wave upon
water, it will be propagated in a uniform motion, and will form in
front of it successive waves whose velocity of propagation is
accelerated.

This may explain why sounds perceived at great distances are
briefer than at small ones. A detonation that gives a quick dead
sound at a few yards is of much longer duration, and softer at a
great distance.

The laws that govern the system of wave propagation are, then,
very complex.

II

II.—If an obstacle be in the way of the waves, there will
occur in each of them an alteration, a break, which it will
carry along with it to a greater or less distance. This succession
of alterations forms a trace behind the obstacle, and in opposition
to the line of the centers. Finally, if the obstacle itself emits
waves in space that are of less intensity then those which meet it,
these little waves will extend in the wake of the large ones, and
will form a trace of parabolic form situated upon the line of the
centers.

III

III.—Let us admit, then, that the sun, through the
peculiar energy that develops upon its surface or in its
atmosphere, engenders in ethereal space successive waves of varying
nature and intensity, as has been said above, and let us admit that
its mechanical waves are traversed obliquely (Fig. 1) by any
spherical body—by a comet, for example; then, under the
excitation of the waves that it is traversing, and through its
velocity, the comet will itself enter into action, and produce
mechanical waves in its turn. As the trace produced in the solar
waves consists of an agitation of the ether on such trace, it will
become apparent, if we admit that every luminous effect is produced
by an excitation—a setting of the ether in vibration. The
mechanical waves engender of themselves, then, an emission of
optical waves that render perceptible the alteration which they
create in each other.

Let a be the position of the comet. The altered wave, a, will
carry along the mark of such alteration in the direction a b, while
at the same time extending transversely the waves emitted by the
comet. During this time the comet will advance to a’, and the wave
will be altered in its turn, and carry such alteration in the
direction, a’ b’.

The succession of all these alterations will be found, then,
upon a curve a” d’ d, whose first elements, on coming from the
comet, will be upon the resultant of the comet’s velocity, and of
the propagation of the solar waves. Consequently, the slower the
motion of the comet, with respect to the velocity of the solar
waves, the closer will such resultant approach the line of centers,
and the more rectilinear will appear the trace or tail of the
comet.

IV

IV.—If the comet have satellites, we shall see, according
to the relative position of these, several tails appear, and these
will seem to form at different epochs. If c and s be the positions
of a comet and a satellite, it will be seen that if, while the
comet is proceeding to c’, the satellite, through its revolution
around it, goes to s’, the traces formed at c and s will be
extended to d and d’, and that we shall have two tails, c’ d and s’
d’, which will be separated at d and d’ and seem to be confounded
toward c’ s’.

V.—When the comet recedes from the sun, the same effect
will occur—the tail will precede it, and will be so much the
more in a line with the sun in proportion as the velocity of the
solar waves exceeds that of the comet.

If we draw a complete diagram (Fig. 4), and admit that the
alteration of the solar waves persists indefinitely, we shall see
(supposing the phenomenon to begin at a) that when the comet is at
a 1, the tail will and be at a 1 b; when it is a 2 the tail will be
at a 2 b’; and when it is at a 4, the tail will have become an
immense spiral, a 4 b”’. As in reality the trace is extinguished
in space, we never see but the origin of it, which is the part of
it that is constantly new—that is to say, the part
represented in the spirals of Fig. 4.

The comet of 1843 crossed the perihelion with a velocity of 50
leagues per second; it would have only required the velocity of the
solar waves’ propagation to have been 500 leagues per second to
have put the tail in a sensibly direct opposition with the sun.

Knowing the angle γ (Fig. 5) that the tangent to the orbit
makes with the sun at a given point, and the angle δ of the
track upon such tangent, as well as the velocity v of the comet, we
can deduce therefrom the velocity V of the solar waves by the
simple expression:

t” being the time taken to pass over aa”.

V

VI.—The tail, then, is not a special matter which is
transported in space with the comet, but a disturbance in the solar
waves, just as sound is an atmospheric disturbance which is
propagated with the velocity of the sonorous wave, although the air
is not transported. The tail which we see in one position, then, is
not that which we see in another; it is constantly renewed.
Consequently, it is easy to conceive how, in as brief a time as it
took the comet of 1843 to make a half revolution round the sun, the
tail which extended to so great a distance appeared to sweep the
180° of space, while at the same time remaining in opposition
to the great luminary.

VI

The spiral under consideration may be represented practically.
If to a vertical pipe we adapt a horizontal one that revolves with
a certain velocity, and throws out water horizontally, it will be
understood that, from a bird’s eye view, the jet will form a
spiral. Each drop of water will recede radially in space, the
spiral will keep forming at the jet, and if, through any reason,
the latter alone be visible, we shall see a nearly rectilinear jet
that will seem to revolve with the pipe.

Finally, if the jet be made to describe a curve, m n (Fig. 4),
while it is kept directed toward the opposite of a point, c, the
projected water will mark the spiral indicated, and this will
continue to widen, and each drop will recede in the direction shown
by the arrows.

VII

VII.—It seems to result from this explanation that all the
planets and their satellites ought to produce identical effects,
and have the appearance of comets. In order to change the
conditions, it suffices to admit that the ethereal mass revolves in
space around the sun with a velocity which is in each place that of
the planets there; and this is very reasonable if, admitting the
nebular hypothesis, we draw the deduction that the cause that has
communicated the velocity to the successive rings has communicated
it to the ethereal mass.

The planets, then, have no appreciable, relative velocity in
space, and for this reason do not produce mechanical waves; and, if
they become capable of doing so through a peculiar energy developed
at their surface, as in the case of the sun, they are still too
weak to give very perceptible effects. The satellites, likewise,
have relatively too feeble velocities.

The comet, on the contrary, directly penetrates the solar waves,
and sometimes has a relatively great velocity in space. If its
proper velocity be of directly opposite direction to that of the
ethereal mass’s rotation, it will then be capable of producing
sufficiently intense mechanical effects to affect our vision.

VIII.—Finally, seeing the slight distances at which these
stars pass the sun, the attraction upon the comet and its
satellites may be very different, and the velocity of rotation of
the latter, being added to or deducted from that of the forward
motion, there may occur (as in the case shown in Fig. 6) a
separation of a satellite from the principal star. The comet then
appears to separate into two, and each part follows different
routes in space; or, as in Fig. 7, one of the satellites may either
fall into the sun or pursue an elliptical orbit and become
periodical, while the principal star may preserve a parabolic
orbit, and make but one appearance.—A. Goupil.

[6]

THE DOUBLE ROLE OF THE STING OF THE HONEY BEE.⁷

Very important and highly interesting discoveries have recently
been made in regard to a double role played by the sting of the
honey bee. These discoveries explain some hitherto inexplicable
phenomena in the domestic economy of the ants. It is already known
that the honey of our honey bees, when mixed with a tincture of
litmus, shows a distinct red color, or, in other words, has an acid
reaction. It manifests this peculiarity because of the volatile
formic acid which it contains. This admixed acid confers upon crude
honey its preservative power. Honey which is purified by treatment
with water under heat, or the so-called honey-sirup, spoils sooner,
because the formic acid is volatilized. The honey of vicious swarms
of bees is characterized by a tart taste and a pungent odor. This
effect is produced by the formic acid, which is present in excess
in the honey. Hitherto it has been entirely unknown in what way the
substratum of this peculiarity of honey, the formic acid in the
honey, could enter into this vomit from the honey stomach of the
workers. Only the most recent investigations have furnished us an
explanation of this process. The sting of the bees is used not only
for defense, but quite principally serves the important purpose of
contributing to the stored honey an antizymotic and antiseptic
substance.

The observation has recently been made that the bees in the
hive, even when they are undisturbed, wipe off on the combs the
minute drops of bee poison (formic acid) which from time to time
exude from the tip of their sting. And this excellent preservative
medium is thus sooner or later contributed to the stored honey. The
more excitable and the more ready to sting the bees are, the
greater will be the quantity of formic acid which is added to the
honey, and the admixture of which good honey needs. The praise
which is so commonly lavished upon the Ligurian race of our honey
bees, which is indisposed to sting—and such praise is still
expressed at the peripatetic gatherings of German
bee-masters—is therefore from a practical point of view a
false praise. Now we understand also why the stingless honey bees
of South America collect little honey. It is well known that never
more than a very small store of honey is found in felled trees
inhabited by stingless Melipona. What should induce the
Melipona to accumulate stores which they could not preserve?
They lack formic acid. Only three of the eighteen different known
species of honey bees of northern Brazil have a sting. A peculiar
phenomenon in the life of certain ants has always been
problematical, but now it finds also its least forced explanation.
It is well known that there are different grain-gathering species
of ants. The seeds of grasses and other plants are often preserved
for years in their little magazines, without germinating. A very
small red ant, which drags grains of wheat and oats into its
dwellings, lives in India. These ants are so small that eight or
twelve of them have to drag on one grain with the greatest
exertion. They travel in two separate ranks over smooth or rough
ground, just as it comes, and even up and down steps, at the same
regular pace. They have often to travel with their booty more than
a thousand meters, to reach their communal storehouse. The renowned
investigator Moggridge repeatedly observed that when the ants were
prevented from reaching their magazines of grain, the seeds begun
to sprout. The same was the case in abandoned magazines of grain.
Hence the ants know how to prevent the sprouting of the grains, but
the capacity for sprouting is not destroyed. The renowned English
investigator John Lubbock, who communicates this and similar facts
in his work entitled “Ants, Bees, and Wasps,” adds that it is not
yet known in what way the ants prevent the sprouting of the
collected grains. But now it is demonstrated that here also it is
only the formic acid, whose preservative influence goes so far that
it can make seed incapable of germination for a determinate time or
continuously.

It may be mentioned that we have also among us a species of ant
which lives on seeds, and stores these up. This is our Lasius
niger, which carries seeds of Viola into its nests, and,
as Wittmack has communicated recently to the Sitzungsberichte der
gesellschaft naturforschender freunde zu Berlin, does the same with
the seeds of Veronica hederaefolia.

Syke states in his account of an Indian ant, Pheidole
providens, that this species collects a great store of
grass-seeds. But he observed that the ants brought their store of
grain into the open air to dry it after the monsoon storms. From
this it appears that the preservative effect of the formic acid is
destroyed by great moisture, and hence this drying process. So that
among the bees the honey which is stored for winter use, and among
the ants the stores of grain which serve for food, are preserved by
one and the same fluid, formic acid.

EDITORIAL NOTE.

This same theory has been suggested many times by our most
advanced American bee-keepers. It has been hinted that this same
formic acid was what made honey a poison to many people, and that
the sharp sting of some honey, notably that from bass wood or
linden, originated in this acid from the poison sac. If this is the
correct explanation, it seems strange that the same kind of honey
is always peculiar for greater or less acidity as the case may be.
We often see bees with sting extended and tipped with a tiny drop
of poison; but how do we know that this poison is certainly mingled
with the honey? Is this any more than a guess?—A.J. Cook,
in Psyche.

[7]

CHLORIDES IN RAINFALL OF 1884.

We are apt to regard the rain solely as a product of
distillation, and, as such, very pure. A little reflection and a
very slight amount of experimental examination will quickly
disabuse those who have this mistaken and popular impression of
their error. A great number of bodies which arise from industrial
processes, domestic combustion of coal, natural changes in
vegetable and animal matter, terrestrial disturbances as tornadoes
and volcanic eruptions, vital exhalations, etc., are discharged
into the atmosphere, and, whether by solution or mechanical
contact, descend to the surface of the earth in the rain, leaving
upon its evaporation in many instances the most incontestable
evidences of their presence. The acid precipitation around alkali
and sulphuric acid works is well known; the acid character of rains
collected near and in cities, and the remarkable ammoniacal
strength of some local rainfalls, have been fully discussed. The
exhaustive experiments of Dr. Angus Smith in Scotland, and the
interesting reports of French examiners, have made the scientific
world familiar, not only qualitatively but quantitatively, with the
chemical nature of some rains, as well as with their solid
sedimentary contents.

Some years ago my attention was unpleasantly drawn to the fact
that the rain water in our use reacted for chlorine; and on finding
this due solely to the washing out from the atmosphere of suspended
particles of chloride of sodium or other chlorides or free
chlorine, it appeared interesting to determine the average amount
of these salts in the rain water of the sea coast. The results
given in this paper refer to a district on Staten Island, New York
harbor, at a point four miles from the ocean, slightly sheltered
from the ocean’s immediate influence by the intervention of low
ranges of hills. They were communicated to the Natural Science
Association of Staten Island, but the details of the observations
may prove of interest to the readers of the Quarterly, and
may there serve as a record more widely accessible.

It has long been recognized that the source of chlorine in
rainfalls near the sea was the sea itself, the amount of chlorides,
putting aside local exceptions arising from cities or
manufactories, increasing with the proximity of the point of
observation to the ocean, and also showing a marked relation to the
exposure of the position chosen to violent storms. Thus the west
coast rainfalls of Ireland contain larger quantities of chlorides
than those of the east, and the table given by Dr. Smith shows the
variations in neighboring localities on the same seafront. The
chlorides of the English rains diminish as the observer leaves the
sea coast. In the following observations the waters of thirty-two
rains were collected, the chlorine determined by nitrate of silver
in amounts of the water varying from one liter to one-half a liter,
and in some instances less. While it is likely that some of the
chlorine was due to the presence of chlorides other than common
salt, as the position of the point of observation is not removed
more than a mile from oil distilleries and smelting and sulphuric
acid works in New Jersey, yet this could not even generally have
been so, as the rain storms came, for the greater number of
instances, from the east, in an opposite direction to the position
of the factories alluded to. It has also been noticed by Mr. A.
Hollick, to whom these observations were of interest, that in heavy
storms a salt film often forms upon fruit exposed to the easterly
gales upon the shores of the island.

The yearly average for chlorine is 0.228 grain per gallon; for
sodic chloride, 0.376 grain. The total rainfall in our region for
1884, as reported by Dr. Draper at Central Park, was 52.25 inches,
somewhat higher than usual, as the average for a series of years
before gives 46 inches; but taking these former figures, we find
that for that year (1884) each acre of ground received, accepting
the results obtained by my examination, 76.24 avoirdupois pounds of
common salt, if we regard the entire chlorine contents of the rains
as due to that body, or 46.23 pounds of chlorine alone.

In comparison with this result, we find that at Caen, in France,
an examination of the saline ingredients of the rain gave for one
year about 85 pounds of mineral matter per acre, of which 40 pounds
were regarded as common salt.

Although chlorine is almost constantly present in plant tissues,
it is not indispensable for most plants, and for those assimilating
it in small amounts, our rainfall would seem to offer an ample
supply. These facts open our eyes to the possible fertilizing
influence of rains, and they also suggest to what extent rains may
exert a corrosive action when they descend charged with acid
vapors.—L.P. Gratacap, in School of Mines
Quarterly.

THE CHROMATOSCOPE.

Some time ago Mr. J.D. Hardy devised an instrument, which he has
named a chromatoscope, so easily made by any one who has a spot
lens that we take the following description from the Journal
of the Royal Microscopical Society: “Its chief purpose is that of
illuminating and defining objects which are nonpolarizable, in a
similar manner to that in which the polariscope defines polarizable
objects. It can also be applied to many polarizable objects. This
quality, combined with the transmission of a greater amount of
light than is obtainable by the polariscope, renders objects thus
seen much more effective. It is constructed as follows: Into the
tube of the spot lens a short tube is made to move freely and
easily. This inner tube has a double flange, the outer one, which
is milled, for rotating, and the inner one for carrying a glass
plate. This plate is made of flat, clear glass, and upon it are
cemented by a very small quantity of balsam three pieces of colored
(stained) glass, blue, red, and green, in the proportion of about
8, 5, and 3. The light from the lamp is allowed to pass to some
extent through the interspaces, and is by comparison a strong
yellow, thus giving four principal colors. Secondary colors are
formed by a combination of the rays in passing through the spot
lens.

“The stained glass should be as rich in color and as good in
quality as possible, and a better effect is obtained by three
pieces of stained glass than by a number of small pieces. The
application of the chromatoscope is almost unlimited, as it can be
used with all objectives up to the 1/8. Transparent objects,
particularly crystals which will not polarize, diatoms, infusoria,
palates of mollusks, etc., can not only be seen to greater
advantage, but their parts can be more easily studied. As its cost
is merely nominal, it can be applied to every instrument, large or
small; and when its merits and its utility by practice are known, I
am confident that it will be considered a valuable accessory to the
microscope.”

Prof. W.O. Atwater, as the results of a series of experiments,
finds, contrary to the general opinion of chemists, that plants
assimilate nitrogen from the atmosphere. They take up the greatest
quantity when supplied with abundant nourishment from the soil.
Well fed plants acquired fully one-half their total nitrogen from
the air. It seems probable that the free nitrogen of the air is in
some way assimilated by the plants.

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