Scientific American Supplement, No. 362, December 9, 1882

V >> Various >> Scientific American Supplement, No. 362, December 9, 1882

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A six-celled destructor kiln burns about 42 tons of refuse in
twenty-four hours, leaving about one-fourth of its bulk of clinkers and
ashes. The clinkers are withdrawn from the furnaces five times each day
and night, or about every two-and-a-half hours, into iron barrows, and
wheeled outside the shed which covers the destructor, and when cold are
wheeled back to the mortar mills, of which there are two at each depot,
each having a revolving pan 8 feet in diameter, with 27-cwt. rollers,
the pan making twenty two revolutions a minute. Forty shovelfuls of
clinkers and twelve of slaked lime make 7 cwt. of mortar in thirty-five
minutes in each pan, which is sold at 5s. 6d. per ton. The engine
driving the two mortar mills has a 14 inch cylinder, 30 inches length
of stroke, and makes sixty revolutions per minute with 45 pounds steam
pressure per square inch in the boiler, when both mortar mills are
running. The boiler is 11 feet long, 8 feet in diameter, and has 132
tubes 4 inches in external diameter, which, together with the external
flues, are cleaned out once a month.

At first sight it would probably appear that no good mortar could be
made from such refuse as has been described, but having passed through
the furnace, the clinkers are, of course, perfectly clean, and with good
lime make a really strong and excellent mortar. They are also largely
used for the foundation of roadways.

The number of men employed is as follows: Two furnace men in the daytime
and two at night. They work from midnight on Sundays to 2 P.M. on
Saturdays, the fires being fully charged and left to burn through the
Sundays. One foreman, who attends also to the running of the engine, and
one mortar man. A watchman attends while the workmen are off.

In addition to a destructor, there is at the Burmautofts depot a
"carbonizer" kiln, in which the sweepings of the vegetable markets are
burned into charcoal. The carbonizer consists of eight vertical cells,
in two sets or stacks of four, separated by a space containing two
double furnaces, back to back, there being a double furnace also at each
end of the eight cells. Each of the stacks of four cells is 15 feet
6 inches high; the ends and middle parts, forming the tops of the
furnaces, being 6 feet high. The block of brick work containing the
eight cells and furnaces is 26 feet 6 inches long and 12 feet 4 inches
wide at the floor level. Each cell is 3 feet 6 inches by 2 feet, and
about 10 feet deep, with a chamber below about 3 feet deep, into which
the charred material falls and is completely burned. The top of the
cells is level with the upper platform, and they are fed through a loose
cover, which is immediately replaced. Inside the cells cast-iron sloping
shelves are hung upon the walls so that their upper edges touch the
walls, but the lower edges are some inches off, so that the hot air of
the furnaces passes upward behind the shelves round the four sides of
the cell in a spiral manner, and out near the top into a vertical flue,
which conducts it down to the horizontal flue at the bottom, which leads
to the chimney. The charcoal is withdrawn from the bottom of the heating
chamber through a sliding plate 2 feet above the floor, and is wheeled
red hot to the charcoal cooler, which is a revolving cylinder, nearly
horizontal, kept cool by water falling upon it, and delivers the
charcoal in two degrees of fineness at the end. It is worked by a small
attached engine, supplied with steam from the boiler before mentioned.
Each cell of the carbonizer can reduce to charcoal 50 cwt. of vegetable
refuse in twenty four hours, but at Leeds not quite so much is put
through. The quantity of market refuse passed through six cells of the
carbonizer varies from 3 to 10 tons a day, and averages about 41/2 tons,
from which 15 cwt. of charcoal is obtained. The fuel for burning the
charcoal is derived from the ash pit refuse, some selected loads being
for that purpose passed over a sloping screen fixed between the upper
platform and the furnace floor, the fine ashes which pass through the
screen being taken away to the manure heaps, and the combustible parts
to the furnaces of the carbonizer. In this way a good deal of the ash
pit refuse is got rid of; it is often one-twelfth part of the whole
quantity.

The carbonizer and the destructor are set 33 feet apart, to allow room
for drawing the furnaces and for the mortar mills, but the space is
hardly sufficient. One man is employed in attending to the carbonizer.

Besides the openings at the top of the destructor through which the ash
pit refuse is fed into the cells, there is a larger opening in each
cell, kept covered usually, through which bed mattresses ordered by the
medical sanitary office to be destroyed can be put into the cells. These
openings are midway between the central openings and the furnace doors,
and whatever is put into the cells through these comes into immediate
contact with the fire. Advantage is taken of these openings for the
destruction of dead animals and diseased meat, and as much as 20 tons in
a year have been passed through the destructor.

The whole works are roofed over. The lower floor is open on two sides,
but the upper one is closed in, with weather boarding at Burmantofts and
with corrugated iron at Armley Road. At the former place the works
were in some measure experimental, and the platform was constructed
of timber, but at Armley Road it is of plate-iron girders, with brick
arching, weight being considered advantageous in reducing the vibration
of carting heavy loads over it.

The cost of each depot has been L4,500, exclusive of land, of which
about an acre is required for the destructor, carbonizer, inclined road,
weigh office, and space. A supply of water is necessary, a good deal
being required for cooling the clinkers. The population of the two
districts belonging to these works is about 160,000.

The author has no longer any connection with the works described, and
for the recent experience of their working he is indebted to Mr.
John Newhouse, the superintendent of the sanitary department of the
corporation.

* * * * *

GREEN WOOD.

The specific volume of the different constituents of green woods has
been estimated by M. Hartig to be as follows, per 1,000 parts: Hard
green wood, fiber stuff, 441; water, 247; air, 312. Soft green wood,
fiber stuff, 279; water, 317, air, 404. Evergreen wood, fiber stuff,
270; water, 335; air, 395. A certain amount of water--7 or 8 per cent in
all--is included with the fiber stuff, showing that about one-third only
of the mass of the wood is solid stuff; the remainder is either water or
air space.

* * * * *

THE ARMITAGE HOUSE.

This house is now in course of erection under the superintendence
of Messrs. Salomons and Ely, in the Claremont road, Pendleton, near
Manchester. The walls are faced in the lower part with red bricks,
and red stone, from the neighborhood of Liverpool, is used for the
window-dressings, etc. The upper part of walls will be faced with
red tiles and half-timber work, and the roof will be covered with
Staffordshire tiles. Lead lights will be largely used in the windows.
Internally, the finish will be almost entirely in real woods, including
walnut for the dining-room and vestibule, pitch-pine for the large hall,
staircase, and billiard-room, ash for the morning-room, and oak for Mr.
Armitage's own room. In all these the ceilings and dados are to be in
wood. The contract for the whole of the above work, amounting to L6,507,
is let to Mr. James Herd, of Manchester.--_Building News_.

[Illustration: SUGGESTIONS IN ARCHITECTURE.--AN ENGLISH COUNTRY
RESIDENCE.]

* * * * *

THE COLLOTYPE PROCESS IN PRACTICE.

That theory and practice are two very different things holds good in
photography especially, and perhaps in no other branch of our art have
so many theoretical formulae been promulgated as in the collotype or
Lichtdruck process. As our readers are aware, we have had an opportunity
of seeing collotype printing in operation in several European
establishments of note, and have, from time to time, published in these
columns our experiences. But requests still come to us so frequently
for information on the process that we have deemed it well to make a
practical summary for the benefit of those who are working--or desire to
work--the method.

The formulae and manipulations here set down are those of Loewy, Albert,
Allgeyer, and Obernetter, four of the best authorities on the subject,
and we can assure our readers there is nothing described but what is
actually practiced.

_Glass Plate for the Printing Block_.--Herr Albert, of Munich, uses
patent plate of nearly half an inch in thickness, as most of his work
is printed upon the Schnell press (machine press). Herr Obernetter, of
Vienna, since he only employs the slower and more careful hand
press, prefers plate glass of ordinary thickness as being handier in
manipulation and better adapted to the common printing-frame.

Herr Loewy, of Vienna, again, uses plate glass a quarter of an inch
thick, as his productions range from the finest to the roughest.

_Preliminary Coating of the Glass Plate_.--Herr Albert's original plan
was to apply a preliminary coating of bichromated gelatine to the thick
glass plate, the film being exposed to light through the back of the
glass, and thus rendered insoluble and tightly cemented to the surface;
this film serving as a basis for the second sensitive coating, that
was afterward impressed by the negative. This double treatment is now
definitely abandoned in most Lichtdruck establishments, and, instead, a
preliminary coating of soluble silicate and albumen dissolved in water
is used.

Herr Loewy's method and formula are as follows: The glass plate is
cleaned, and coated with--

Soluble glass. 3 parts.
White of egg. 7 "
Water. 9 to 10 "

The soluble glass must be free from caustic potash. The mixture, which
must be used fresh, is carefully filtered, and spread evenly over the
previously cleaned glass plate. The superfluous liquid is flowed off,
and the film dried either spontaneously or by slightly warming. The film
is generally dry in a few minutes, when it is rinsed with water, and
again dried; at this stage the plate bears an open, porous film,
slightly opalescent--so slight, however, as only to be observed by an
experienced eye.

_Application of the Sensitive Film_.--We now come to the second stage of
the process, the application of a film of bichromated gelatine to the
plate.

Herr Loewy's formula is as follows:

Bichromate of potash. 16 grammes.
Gelatine. 21/2 ounces.
Water. 20 to 22 "

According to the weather, the amount of water must be varied; but in any
case the solution is a very fluid one. An ounce is about 35 grammes, as
most of our readers know. A practical collotypist sees at a glance the
quality of the prepared plate, without any preliminary testing. A good
preliminary film is a glass that is transparent, yet slightly dull; the
film is so thin, you can scarcely believe it is there. The plate is
slightly warmed upon a slate slab, underneath which is a water bath; it
is then flooded with the above mixture of bichromated gelatine, leaving
only sufficient to make a very thin film. When coated, the plate is
placed in the drying chamber.

_Drying the Sensitive Film_.--Much depends upon the drying. A water
bath with gas burner underneath is used for heating, and a slate slab,
perfectly level, receives the glass plate. The drying chamber is kept at
an even temperature of 50 deg. C.

The object to be attained is a fine grain throughout the surface of the
gelatine, and unless this grain is satisfactory the finished printing
block never will be. If the gelatine film be too thick, then the grain
will be coarse; or, again, if the temperature in drying be too high,
there will be no grain at all. The drying is complete in two or three
hours, and should not take longer.

_The Negative to be Printed from_.--The sensitive film being upon the
surface of a thick glass plate, it is necessary that the cliche or
negative employed should be upon patent plate, or not upon glass at all,
so as to insure perfect contact. Best of all, is to employ a stripped
negative, in which case absolute contact is insured in printing. It is
only in these circumstances that the most perfect impression can be
secured. If the negative is otherwise satisfactory, and only requires
stripping, it must be upon a leveling stand, and fluid gelatine of a
tolerable consistence is poured over it. When dry, a pen-knife is run
around the margin, and the film leaves the glass without any trouble.

Herr Obernetter says that many of the negatives he receives have to be
reproduced before they can be transformed into Lichtdruck plates, and
he employs either the wet collodion process or the graphite method,
according to circumstances. If the copy is desired to be softer than the
original, collodion is employed; if vigor be desired, graphite is used,
and here is his formula:

Dextrine. 62 grains.
Ordinary white sugar. 77 "
Bichromate of ammonia. 30.8 "
Water. 3.21 ounces.
Glycerine. 2 to 8 drops.

The film is dried at a temperature of 130 deg. to 140 deg. F. in about ten
minutes, and while still warm is printed under a negative in diffused
light for a period of five to fifteen minutes. In a well-timed print
the image is slightly visible; the plate is again warmed a little above
atmospheric temperature in a darkened room, and then fine levigated
graphite is applied with a fine dusting brush, a sheet of white paper
being held underneath to judge of the effect. Breathing upon the film
renders it more capable of attracting the powder. When the desired vigor
has been attained, the superfluous powder is dusted off, and the plate
coated with normal collodion. Afterward the film is cut through at the
margins of the plate by means of a sharp knife, and put into water. In a
little while--from two to five minutes--the collodion, with the image,
will be detached from the glass; the film is at once turned over in the
water, and brought out upon the glass plate. Under a soft jet of water
any air-bubbles that may exist between the collodion and the glass are
removed, and then a solution of gum arabic (two grammes of gum dissolved
in one hundred grammes of water) is poured over, and the film is allowed
to dry spontaneously.

_Exposure of the Printing Block under the Negative_.--The exposure
is very rapid. Any one conversant with photolithographic work will
understand this. At any rate, every photographer knows that bichromated
gelatine is much more rapid than the chloride of silver he generally has
to do with.

There is no other way of measuring the exposure than by the photometer
or personal experience, and the latter is by far the best.

After leaving the printing frame, the plate is immersed in cold water.
Here it remains at discretion for half an hour, or an hour; the purpose,
of course, being to wash out the soluble bichromate. It is when the
print comes out of this bath that judgment is passed upon it. An
experienced eye tells at once what it is fit for. If it is yellow, the
yellowness must be of the slightest; indeed, Herr Furkl (the manager of
Herr Loewy's Lichtdruck department) will not admit that a good plate is
yellow at all. A yellow tint means that it will take up too much ink
when the roller is passed over it. The plates of Herr Obernetter,
however, are rather more yellow than Herr Loewy's--certainly only a
tinge, but still yellow; and Herr Obernetter's work proves, at any rate,
that the yellowish tinge is by no means inseparable from good results.

The washed and dried plate should appear like a design of ground and
polished glass. The ground glass appearance is given by the grain. If
there are pure high-lights (almost transparent) and opalescent shadows,
the plate is a good one.

_Printing from the Block_.--We have now a printing-block ready for the
press. If it is to be printed by machinery--that is to say, upon a
Schnell press--the surface is etched; if it has to be more carefully
handled in a hand press, etching is rarely resorted to; it is moistened
only with glycerine and water. To etch a plate for a Schnell press, it
is placed upon a leveling stand, and the following solution is poured
upon it:

Glycerine............................. 150 parts.
Ammonia................................ 50 "
Nitrate of potash (saltpeter).......... 5 "
Water.................................. 25 "

Another equally good formula, recommended by Allgeyer, who managed Herr
Albert's Lichtdruck printing for some years, is:

Glycerine............................. 500 parts.
Water................................. 500 "
Chloride of sodium (common salt)...... 15 "

In lieu of common salt, 15 parts of hyposulphite of soda, or other
hygroscopic salt, such as chloride of calcium, may be employed.

The etching fluid is permitted to remain upon the image for half an
hour. During this time, by gently moving the finger to and fro over the
surface, the swelling or relief of the image can be distinctly felt. The
plate is not washed, but the etching fluid simply poured off, so that
the film remains impregnated with the glycerine and water; at the most,
a piece of bibulous paper is used to absorb any superfluous quantity of
the etching fluid. After etching, the plate is taken straight to the
printing press. The inking up and printing are done very much as
in lithography. If it requires a practiced hand to produce a good
lithographic print, it stands to reason that in dealing with a gelatine
printing block, instead of a stone, skill and practice are more
necessary still. Therefore at this point the photographer should hand
over the work to the lithographer, or rather the Lichtdruck printer.
It is only by coaxing judiciously, with roller and sponge, that a good
printing block can be obtained, and no amount of teaching theoretically
can beget a good printer. To appreciate how skillful a printer must be,
it is only necessary to see the imperfect proofs that first result, and
to watch how these are gradually improved by dint of rolling, rubbing,
etching, cleaning, etc. In all Lichldruck establishments, two kinds of
rollers are used, viz., of leather and glue. In some establishments,
too, they employ two kinds of ink; but Herr Loewy manages to secure
delicacy and vigor at the same time by using one ink, but rolling up
with two kinds of roller.

Collotype printing is not merely done by hand presses, but is also
done by machinery. At Herr Albert's a gas engine of six-horse power is
employed to drive the machines, and each machine requires the
attention of a skilled mechanic and a girl. The press is very like the
lithographic quick press. Upon a big steel bed lies the little collotype
block. The glass printing block, with its brownish film of gelatine,
moves horizontally to and fro, and, as it does so, passes under half a
dozen rollers, which not only supply ink, but disperse it. Some of the
rollers are of leather and others of glue, and, whenever the printing
block retires from underneath them, an ink slab takes the place of the
block, and imparts more ink to the rollers; sometimes as many as eight
rollers are used, for the difficulty of machine printing is to apply the
ink as delicately and equally as possible. It is necessary at intervals
to damp the block, and when the printer in charge finds this to be the
case, he stops the press, and applies a little glycerine and water
with a cloth or sponge; then a leather roller is passed over to remove
superfluous moisture, and the press is again started.

Herr Obernetter relies upon the Star or Stern press--a small
lithographic press--one man sufficing to manage it, who turns a wheel
with large spokes, reminding one of the steering wheel of a ship. The
Lichtdruck plate, gelatine film upward, is laid upon a sheet of plate
glass by way of a bed, the plate having first been treated with a
solution of glycerine and water; it is then inked up as previously
described, except that Herr Obernetter uses two kinds of ink--a thick
one and a thin--applied by two rollers of glue. In the first place, a
moist sponge is rubbed over the surface; then a soft roller covered with
wash-leather, and of the appearance of crepe, is passed over two or
three times to remove surplus moisture; then a roller charged with thick
ink is put on, and then another with thin is applied. It takes fully
five minutes to sponge and roll up a plate, the rolling being done
gently and firmly. A sheet of paper is now laid upon the plate, the
tympan is lowered, and the scraper adjusted with due pressure; a
revolution of the wheel completes the printing, the well-known scraping
action of the lithographic press being used in the operation.

[Illustration: FIG. 1.--ORDINARY NAPHTHA LIGHTER OF MR. LOISEAU.]

Some Lichtdruck prints are printed upon thick plate-paper, and are ready
for binding without further ado, these being for book illustrations.
Other pictures, that are to pass muster among silver photographs, are,
on the other hand, printed upon fine thin paper, and then sized by
dipping in a thin solution of gelatine; after drying, they are further
dipped in a solution of shellac and spirit.--_Photo. News_.

* * * * *

DOMESTIC ELECTRICITY.

Among the most valuable, and, up to the present time, the least
generally appreciated services that electricity can render for domestic
purposes is that of its application in lighters. At the present epoch
of indifferent matches, to have, instantaneously, a light by pulling
a cord, pressing on a button, or turning a cock, is a thing worthy of
being taken into serious consideration; and our own personal experience
permits us to assert that, regarded from this point of view, electricity
is capable of daily rendering inappreciable services.

According to the nature of the application that is to be made of them,
the places in which they are to be put, and the combustible that they
are to inflame, etc., electric lighters vary greatly in form and
arrangement.

We shall limit ourselves here to pointing out the simplest and most
practical of the numerous models of such apparatus that have been
constructed up to the present time. All those that we shall describe
are based on the incandescence of a platinum wire. A few have been
constructed based on the induction spark, but they are more complicated
and expensive, and have not entered into practical use. Before
commencing to describe these apparatus, we shall make a remark in regard
to the piles for working them, and that is that we prefer for this
purpose Leclanche elements with agglomerated plates and a large surface
of zinc. In order to bring about combustion in any given substance, it
is necessary to bring near it an incandescent body raised to a certain
temperature, which varies with the nature of the said substance, and
which is quite low for illuminating gas, higher for petroleum, and a
white heat for a wax taper or a candle. We have said that we make use
exclusively of a platinum wire raised momentarily to incandescence by
the passage of an electric current. The temperature of such wire will
depend especially upon the intensity of the current traversing it;
and, if this is too great, the platinum (chosen because of its
inoxidizability and its elevated melting point) will rapidly melt;
while, if the intensity is too little, the temperature reached by the
wire will itself be too low, and no inflammation will be brought about.
Practice soon indicates a means of obviating these two inconveniences,
and teaches how each apparatus may be placed under such conditions that
the wire will hardly ever melt, and that the lighting will always be
effected. For the same intensity of current that traverses the wire,
the temperature of the latter might be made to vary by diminishing or
increasing its diameter. A very fine wire will attain a red heat through
a very weak current, but it would be very brittle, and subject to break
at the least accident. For this reason it becomes necessary to employ
wires a little stronger, and varying generally from one to two-tenths
of a millimeter in diameter. The current then requires to be a little
intenser. The requisite intensity is easily obtained with elements
of large surface, which have a much feebler internal resistance than
porous-cup elements; and since, for a given number of elements, the
intensity of the current decreases in measure as the internal resistance
of the elements increases, it becomes of interest to diminish such
internal resistance as much as possible. The platinum wires are usually
rolled spirally, with the object in view of concentrating the heat into
a small space, in order to raise the temperature of the wire as much as
possible. There is thus need of a less intense current to produce the
inflammation than with a wire simply stretched out. In fact, the same
wire traversed by a current of constant intensity scarcely reaches a
_red_ heat when it is straight, while it attains a _white_ heat when it
is wound spirally, because, in the latter case, the cooling surface is
less.

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