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SCIENTIFIC AMERICAN SUPPLEMENT NO. 446




NEW YORK, JULY 19, 1884

Scientific American Supplement. Vol. XVIII, No. 446.

Scientific American established 1845

Scientific American Supplement, $5 a year.

Scientific American and Supplement, $7 a year.


* * * * *

TABLE OF CONTENTS

I. CHEMISTRY. - Tin in Canned Foods. - By Prof. ATTFIELU. - Small
amount of tin found. - Whence come these small particles. - No
cause for alarm.

II. ENGINEERING AND MECHANICS. - The Windmill. - By JAMES
W. HILL. - The Eclipse wind. - Other wind mills. - Their operation,
use, etc.

The Pneumatic Dynamite Gun. - With engraving of pneumatic
dynamite gun torpedo vessel.

Rope Pulley Friction Brake. - 3 figures.

Wire Rope Towage. - Treating of the system of towage by hauling
in a submerged wire rope as used on the River Rhine, boats
employed, etc. - With engraving of wire rope tug boat.

Improved Hay Rope Machine. - With engraving.

The Anglesea Bridge, Cork. - With engraving.

Portable Railways. - By M DECAUVILLE. - Narrow gauge roads
in Great Britain. - M. Decauvilie's system. - Railways used at the
Panama Canal, in Tunis, etc.

III. TECHNOLOGY. - Improved Pneumatic Filtering Presses, and the
Processes in which they are employed. - 2 engravings.

Pneumatic Malting.

A New Form of Gas Washer. - Manner in which it is used. - By
A. BANDSEPT. - 2 figures.

IV. ELECTRICITY, HEAT, ETC. - Gerard's Alternating Current
Machine. - 2 engravings.

Automatic Fast Speed Telegraphy. - By THEO. F. TAYLOR. - Speed
determined by resistance and static capacity. - Experiments
Taylor's system. - With diagram.

Theory of the Action of the Carbon Microphone. - What is it?
- 2 figures.

The Dembinski Telephone Transmitter. - 3 figures.

New Gas Lighters. - Electric lighters. - 3 engravings.

Distribution of Heat which is developed by Forging.

V. ARCHITECTURE, ART. ETC. - Villa at Dorking. - An engraving.

Arm Chair in the Louvre Collection.

VI. GEOLOGY. - The Deposition of Ores. - By J.S. NEWBERRY. - Mineral
Veins. - Bedded veins. - Theories of ore deposit. - Leaching
of igneous rocks.

VII. NATURAL HISTORY, ETC. - Habits of Burrowing Crayfishes
in the U.S. - Form and size of the burrows and mounds. - Obtaining
food. - Other species of crayfish. - 3 figures.

Our Servants, the Microbes. - What is a microbe? - Multiplication.
- Formation of spores. - How they live. - Different groups
of bacteria. - Their services.

VIII. HORTICULTURE. - A New Stove Climber. - _(Ipomæa thomsoniana)_

Sprouting of Palm Seeds.

History of Wheat.

IX. MISCELLANEOUS. - Technical Education in America. - Branches
of study most prominent in schools of different States.

The Anæsthetics of Jugglers. - Fakirs of the Indies. - Processes
employed by them. - Anæsthetic plants.

Epitaphium Chymicum. - An epitaph written by Dr. GODFREY.

* * * * *




IMPROVED FILTER PRESSES.


Hitherto it has been found that of all the appliances and methods for
separating the liquid from the solid matters, whether it is in the case
of effluents from tanneries and other manufactories, or the ocherous and
muddy sludges taken from the settling tanks in mines, some of which
contain from 90 to 95 per cent. of water, the filter press is the best
and the most economical, and it is to this particular process that
Messrs. Johnson's exhibits at the Health Exhibition, London, chiefly
relate. Our engravings are from _The Engineer_. A filter press consists
of a number of narrow cells of cast iron, shown in Figs. 3 and 4, held
together in a suitable frame, the interior frames being provided with
drainage surfaces communicating with outlets at the bottom, and covered
with a filtering medium, which is generally cloth or paper. The interior
of the cells so built up are in direct communication with each other, or
with a common channel for the introduction of the matter to be filtered,
and as the only exit is through the cloth or paper, the solid portion is
kept back while the liquid passes through and escapes by the drainage
surfaces to the outlets. The cells are subjected to pressure, which
increases as the operation goes on, from the growing resistance offered
by the increasing deposit of solid matter on the cloths; and it is
therefore necessary that they should be provided with a jointing strip
around the outside, and be pressed together sufficiently to prevent any
escape of liquid. In ordinary working both sides of the cell are exposed
to the same pressure, but in some cases the feed passages become choked,
and destroy the equilibrium. This, in the earlier machines, gave rise to
considerable annoyance, as the diaphragms, being thin, readily collapsed
at even moderate pressures; but recently all trouble on this head has
been obviated by introducing the three projections near the center, as
shown in the cuts, which bear upon each other and form a series of stays
from one end of the cells to the other, supporting the plates until the
obstruction is forced away. We give an illustration below showing the
arrangement of a pair of filter presses with pneumatic pressure
apparatus, which has been successfully applied for dealing with sludge
containing a large amount of fibrous matter and rubbish, which could not
be conveniently treated with by pumps in the ordinary way. The sludge is
allowed to gravitate into wrought iron receivers placed below the floor,
and of sufficient size to receive one charge. From these vessels it is
forced into the presses by means of air compressed to from 100 lb. to
120 lb. per square inch, the air being supplied by the horizontal pump
shown in the engraving. The press is thus almost instantaneously filled,
and the whole operation is completed in about an hour, the result being
a hard pressed cake containing about 45 per cent. of water, which can be
easily handled and disposed of as required. The same arrangement is in
use for dealing with sewage sludge, and the advantages of the compressed
air system over the ordinary pumps, as well as the ready and cleanly
method of separating the liquid, will probably commend itself to many of
our readers. We understand that from careful experiments on a large
scale, extending over a period of two years, the cost of filtration,
including all expenses, has been found to be not more than about 6d. per
ton of wet sludge. A number of specimens of waste liquors from factories
with the residual matters pressed into cakes, and also of the purified
effluents, are exhibited. These will prove of interest to many, all the
more so since in some instances the waste products are converted into
materials of value, which, it is stated, will more than repay for the
outlay incurred.

[Illustration: Fig. 3. Fig 4.]

Another application of the filter press is in the Porter-Clark process
of softening water, which is shown in operation. We may briefly state
that the chief object is to precipitate the bicarbonates of lime and
magnesia held in solution by the water, and so get rid of what is known
as the temporary hardness. To accomplish this, strong lime water is
introduced in a clear state to the water to be softened, the quantity
being regulated according to the amount of bicarbonates in solution. The
immediate effect of this is that a proportion of the carbonic acid of
the latter combines with the invisible lime of the clear lime water,
forming a chalky precipitate, while the loss of this proportion of
carbonic acid also reduces the invisible bicarbonates into visible
carbonates. The precipitates thus formed are in the state of an
impalpable powder, and in the original Clark process many hours were
required for their subsidence in large settling tanks, which had to be
in duplicate in order to permit of continuous working. By Mr. Porter's
process, however, this is obviated by the use of filter presses, through
which the chalky water is passed, the precipitate being left behind,
while, by means of a special arrangement of cells, the softened and
purified water is discharged under pressure to the service tanks. Large
quantities can thus be dealt with, within small space, and in many cases
no pumping is required, as the resistance of the filtering medium being
small, the ordinary pressure in the main is but little reduced. One of
the apparatus exhibited is designed for use in private mansions, and
will soften and filter 750 gallons a day. In such a case, where it would
probably be inconvenient to apply the usual agitating machinery, special
arrangements have been made by which all the milk of lime for a day's
working is made at one time in a special vessel agitated by hand, on the
evening previous to the day on which it is to be used. Time is thus
given for the particles of lime to settle during the night. The clear
lime water is introduced into the mixing vessel by means of a charge of
air compressed in the top of a receiver, by the action of water from the
main, the air being admitted to the milk of lime vessel through a
suitable regulating valve. A very small filter suffices for removing the
precipitate, and the clear, softened water can either be used at once,
or stored in the usual way. The advantages which would accrue to the
community at large from the general adoption of some cheap method of
reducing the hardness of water are too well known to need much comment
from us.

* * * * *




PNEUMATIC MALTING.


According to K. Lintner, the worst features of the present system of
malting are the inequalities of water and temperature in the heaps and
the irregular supplies of oxygen to, and removal of carbonic acid from,
the germinating grain. The importance of the last two points is
demonstrated by the facts that, when oxygen is cut off, alcoholic
fermentation - giving rise to the well-known odor of apples - sets in in
the cells, and that in an atmosphere with 20 per cent. of carbonic acid,
germination ceases. The open pneumatic system, which consists in drawing
warm air through the heaps spread on a perforated floor, should yield
better results. All the processes are thoroughly controlled by the eye
and by the thermometer, great cleanliness is possible, and the space
requisite is only one-third of that required on the old plan. Since May,
1882, this method has been successfully worked at Puntigam, where plant
has been established sufficient for an annual output of 7,000 qrs. of
malt. The closed pneumatic system labors under the disadvantages that
from the form of the apparatus germination cannot be thoroughly
controlled, and cleanliness is very difficult to maintain, while the
supply of oxygen is, as a rule, more irregular than with the open
floors.

[Illustration: IMPROVED PNEUMATIC FILTERING PRESSES.]

* * * * *




A NEW FORM OF GAS WASHER.

By A. BANDSEPT, of Brussels.


The washer is an appliance intended to condense and clean gas, which, on
leaving the hydraulic main, holds in suspension a great many properties
that are injurious to its illuminating power, and cannot, if retained,
be turned to profitable account. This cleaning process is not difficult
to carry out effectually; and most of the appliances invented for the
purpose would be highly efficacious if they did not in other respects
present certain very serious inconveniences. The passage of the gas
through a column of cold water is, of course, sufficient to condense it,
and clear it of these injurious properties; but this operation has for
its immediate effect the presentation of an obstacle to the flow of the
gas, and consequently augmentation of pressure in the retorts. In order
to obviate this inconvenience (which exists notwithstanding the use of
the best washers), exhausters are employed to draw the gas from the
retorts and force it into the washers. There is, however, another
inconvenience which can only be remedied by the use of a second
exhauster, viz., the loss of pressure after the passage of the gas
through the washer - a loss resulting from the obstacle presented by this
appliance to the steady flow of the gas. Now as, in the course of its
passage through the remaining apparatus, on its way to the holder, the
gas will have to suffer a considerable loss of pressure, it is of the
greatest importance that the washer should deprive it of as little as
possible. It will be obvious, therefore, that a washer which fulfills
the best conditions as far as regards the cleaning of the gas will be
absolutely perfect if it does not present any impediment to its flow.
Such an appliance is that which is shown in the illustration on next
page. Its object is, while allowing for the washing being as vigorous
and as long-continued as may be desired, to draw the gas out of the
retorts, and, having cleansed it perfectly from its deleterious
properties, to force it onward. The apparatus consequently supplies the
place of the exhauster and the scrubber.

The new washer consists of a rectangular box of cast iron, having a
half-cylindrical cover, in the upper part of which is fixed a pipe to
carry off the gas. In the box there is placed horizontally a turbine,
the hollow axis of which serves for the conveyance of the gas into the
vessel. For this purpose the axis is perforated with a number of small
holes, some of which are tapped, so as to allow of there being screwed
on to the axis, and perpendicularly thereto, a series of brooms made of
dog grass, and having their handles threaded for the purpose. These
brooms are arranged in such a way as not to encounter too great
resistance from contact with the water contained in the vessel, and so
that the water cast up by them shall not be all thrown in the same
direction. To obviate these inconveniences they are fixed obliquely to
the axis of the central pipe, and are differently arranged in regard to
each other. A more symmetrical disposition of them could, however, be
adopted by placing them zigzag, or in such a way as to form two helices,
one of which would move in a particular direction, and the other in a
different way. The central pipe, furnished with its brooms, being set in
motion by means of a pulley fixed upon its axis (which also carries a
flywheel), the gas, drawn in at the center, and escaping by the holes
made in the pipe, is forced to the circumference of the vessel, where it
passes out.

The effect of this washer is first, to break up the current of gas, and
then force it violently into the water; at the same time sending into it
the spray of water thrown up by the brooms. This double operation is
constantly going on, so that the gas, having been saturated by the
transfusion into it of a vigorous shower of water (into the bulk of
which it is subsequently immersed), is forced, on leaving the water, to
again undergo similar treatment. The same quantity of gas is therefore
several times submitted to the washing process, till at length it finds
its way to the outlet, and makes its escape. The extent to which the
washing of the gas is carried is, consequently, only limited by the
speed of the apparatus, or rather by the ratio of the speed to the
initial pressure of the gas. This limit being determined, the operation
may be continued indefinitely, by making the gas pass into several
washers in succession. There is, therefore, no reason why the gas should
not, after undergoing this treatment, be absolutely freed of all those
properties which are susceptible of removal by water. In fact, all that
is requisite is to increase the dimensions of the vessel, so as to
compel the gas to remain longer therein, and thus cause it to undergo
more frequently the operation of washing. These dimensions being fixed
within reasonable limits, if the gas is not sufficiently washed, the
speed of the apparatus may be increased; and the degree of washing will
be thereby augmented. If this does not suffice, the number of turbines
may be increased, and the gas passed from one to the other until the gas
is perfectly clean. This series of operations would, however, with any
kind of washer, result in thoroughly cleansing the gas. The only thing
that makes such a process practically impossible is the very
considerable or it may be even total loss of pressure which it entails.
By the new system, the loss of pressure is _nil_, inasmuch as each
turbine becomes in reality an exhauster. The gas, entering the washer at
the axis, is drawn to the circumference by the rotatory motion of the
brooms, which thus form a ventilator. It follows, therefore, that on
leaving the vessel the gas will have a greater pressure than it had on
entering it; and this increase of pressure may be augmented to any
desired extent by altering the speed of rotation of the axis, precisely
as in the case of an exhauster.

Forcing the gas violently into water, and at the same time dividing the
current, is evidently the most simple, rational, and efficient method of
washing, especially when this operation is effected by brooms fixed on a
shaft and rotated with great speed. Therefore, if there had not been
this loss of pressure to deal with - a fatal consequence of every violent
operation - the question of perfect washing would probably have been
solved long ago. The invention which I have now submitted consists of an
arrangement which enables all loss of pressure to be avoided, inasmuch
as it furnishes the apparatus with the greatest number of valuable
qualities, whether regarded from the point of view of washing or that of
condensation.

[Illustration: Longitudinal Section. Elevation. Transverse Section.]

Referring to the illustration, the gas enters the washer by the pipe, A,
which terminates in the form of a [Symbol: inverted T]. One end (a) of
this pipe is bolted to the center of one of the sides of the cylindrical
portion of the case, in which there is a hole of similar diameter to the
pipe; the other (a') being formed by the face-plate of a stuffing-box,
B, through which passes the central shaft, C, supported by the
plummer-block, D, as shown. This shaft has upon its opposite end a plate
perforated with holes, E, which is fixed upon the flange of a horizontal
pipe, F. This pipe is closed at the other end by means of a plate, E',
furnished with a spindle, supported by a stuffing-box, B', and carrying
a fly-wheel, G. The central pipe, F, is perforated with a number of
small holes. The gas entering by the pipe, A, makes its way into the
central pipe through the openings in the plate, E, and passes into the
cylindrical case through the small holes in the central pipe, which
carries the brooms, H. These are caused to rotate rapidly by means of
the pulley, I; and thus a constant shower of water is projected into the
cylindrical case. When the gas has been several times subjected to the
washing process, it passes off by the pipe, K. Fresh cold water is
supplied to the vessel by the pipe, L; and M is the outlet for the
tar. - _Journal of Gas Lighting_.

* * * * *




THE WIND MILL.

[Footnote: A paper read before the Engineers' Club of St. Louis, 1884.]

By JAMES W. HILL.


In the history of the world the utilization of the wind as a motive
power antedates the use of both water and steam for the same purpose.

The advent of steam caused a cessation in the progress of wind power,
and it was comparatively neglected for many years. But more recently
attention has been again drawn to it, with the result of developing
improvements, so that it is now utilized in many ways.

The need in the West of a motive power where water power is rare and
fuel expensive has done much to develop and perfect wind mills.

Wind mills, as at present constructed in this country, are of recent
date.

The mill known as the "Eclipse" was the first mill of its class built.
It is known as the "solid-wheel, self-regulating pattern," and was
invented about seventeen years ago. The wind wheel is of the rosette
type, built without any joints, which gives it the name "solid wheel,"
in contradistinction to wheels made with loose sections or fans hinged
to the arms or spokes, and known as "section wheel mills."

The regulation of the Eclipse mill is accomplished by the use of a small
adjustable side vane, flexible or hinged rudder vane, and weighted
lever, as shown in Plate 1 (on the larger sizes of mills iron balls
attached to a chain are used in place of the weighted lever). The side
vane and weight on lever being adjustable, can be set to run the mill at
any desired speed.

Now you will observe from the model that the action of the governing
mechanism is automatic. As the velocity of the wind increases, the
pressure on the side vane tends to carry the wind wheel around edgewise
to the wind and parallel to the rudder vane, thereby changing the angle
and reducing the area exposed to the wind; at the same time the lever,
with adjustable weight attached, swings from a vertical toward a
horizontal position, the resistance increasing as it moves toward the
latter position. This acts as a counterbalance of varying resistance
against the pressure of the wind on the side vane, and holds the mill at
an angle to the plane of the wind, insuring thereby the number of
revolutions per minute required, according to the position to which the
governing mechanism has been set or adjusted.

If the velocity of the wind is such that the pressure on the side vane
overcomes the resistance of the counter weight, then the side vane is
carried around parallel with the rudder vane, presenting only the edge
of the wind wheel or ends of the fans to the wind, when the mill stops
running.

This type of mill presents more effective wind receiving or working
surface when in the wind, and less surface exposed to storms when out of
the wind, than any other type of mill. It is at all times under the
control of an operator on the ground.

A 22-foot Eclipse mill presents 352 square feet of wind receiving and
working surface in the wind, and only 9½ square feet of wind resisting
surface when out of the wind.

Solid-wheel mills are superseding all others in this country, and are
being exported largely to all parts of the world, in sizes from 10 to 30
feet in diameter. Many of these mills have withstood storms without
injury, where substantial buildings in the immediate vicinity have been
badly damaged. I will refer to some results accomplished with pumping
mills:

In the spring of 1881 there was erected for Arkansas City, Kansas, a
14-foot diameter pumping wind mill; a 32,000-gallon water tank, resting
on a stone substructure 15 feet high, the ground on which it stands
being 4 feet higher than the main street of the town. One thousand four
hundred feet of 4-inch wood pipe was used for mains, with 1,200 feet of
1½-inch wrought iron pipe. Three 3-inch fire hydrants were placed on the
main street. The wind mill was located 1,100 feet from the tank, and
forced the water this distance, elevating it 50 feet. We estimate that
this mill is pumping from 18,000 to 20,000 gallons of water every
twenty-four hours. We learned that these works have saved two buildings
from burning, and that the water is being used for sprinkling the
streets, and being furnished to consumers at the following rates per
annum: Private houses, $5; stores, $5; hotels, $10; livery stables, $15.
At these very low rates, the city has an income of $300 per annum. The
approximate cost of the works was $2,000. This gives 15 per cent.
interest on the investment, not deducting anything for repairs or
maintenance, which has not cost $5 per annum so far.

[Illustration: Plate 2. THE ECLIPSE WIND MILL.]

In June, 1883, a wind water works system was erected for the city of
McPherson, Kansas, consisting of a 22-foot diameter wind mill on a
75-foot tower, which pumps the water out of a well 80 feet deep, and
delivers it into a 60,000-gallon tank resting on a substructure 43 feet
above the ground. Sixteen hundred feet of 6-inch and 300 feet of 4-inch
cast iron pipe furnish the means of distribution; eight 2½-inch double
discharge fire hydrants were located on the principal streets. A gate
valve was placed in the 6-inch main close to the elbow on lower end of
the down pipe from the tank. This pipe is attached to the bottom of the
tank; another pipe was run up through the bottom of tank 9 feet (the


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Online LibraryVariousScientific American Supplement, No. 446, July 19, 1884 → online text (page 1 of 10)