Scientific American Supplement, No. 446, July 19, 1884
by
Various
Part 1 out of 3
Produced by Jon Niehof, Don Kretz, Juliet Sutherland, Charles Franks
and the DP Team
[Illustration]
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.--_(Ipomaea 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 Anaesthetics of Jugglers.--Fakirs of the Indies.--Processes
employed by them.--Anaesthetic 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 91/2 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
11/2-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 21/2-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
tank being 18 feet deep), and carried down to a connection with the main
pipe just outside the gate valve. The operation of this arrangement is
as follows:
The gate valve being closed, the water cannot be drawn below the 9-foot
level in tank, which leaves about 35,000 gallons in store for fire
protection, and is at once available by opening the gate valve referred
to. The tank rests on ground about 5 feet above the main streets, which
gives a head of 57 feet when the tank is half full. The distance from
tank to the farthest hydrant being so short, they get the pressure due
to this head at the hydrant, when playing 2-inch, or 1-1/8-inch streams,
with short lines of 21/2-inch hose; this gives fair fire streams for a
town with few if any buildings over two stories high. It is estimated
that this mill is pumping from 30,000 to 38,000 gallons on an average
every twenty-four hours. There is an automatic device attached to this
mill, which stops it when the tank is full, but as soon as the water in
the tank is lowered, it goes to pumping again. The cost of these works
complete to the city was a trifle over $6,000.
In November last a wind mill 18 feet in diameter was erected over a coal
mine at Richmond, in this State. The conditions were as follows:
The mine produces 11,000 gallons of water every twenty-four hours. The
sump holds 11,000 gallons. Two entries that can be dammed up give a
storage of 16,500 gallons, making a total storage capacity of 27,500
gallons. It takes sixty hours for the mine to produce this quantity of
water, which allows for days that the wind does not blow. The average
elevation that the water has to be raised is 65 feet, measuring from
center of sump to point of delivery. A record of ninety days shows that
this mill has kept the mine free from water with the exception of 6,000
gallons, which was raised in the boxes that the coal is raised in. The
location is not good for a wind mill, as it stands in a narrow ravine or
valley a short distance from its mouth, which terminates at the bottom
lands of the Missouri River. This, taken in connection with the fact
that the grit in the water cuts the pump plunger packing so fast that in
a short time the pump will not work up to its capacity, accounts for the
apparent small amount of power developed by this mill.
There has been some discussion of late in regard to the horse power of
wind mills, one party claiming that they were capable of doing large
amounts of grinding and showing a development of power that was
surprising to the average person unacquainted with wind mills, while the
other party has maintained that they were not capable of developing any
great amount of power, and has cited their performance in pumping water
to sustain his argument. My experience has has led me to the conclusion
that pumping water with a wind mill is not a fair test of the power that
it is capable of developing, for the following reasons:
A pumping wind mill is ordinarily attached to a pump of suitable size to
allow the mill to run at a mean speed in an 8 to 10 mile wind. Now, if
the wind increases to a velocity of 16 to 20 miles per hour, the mill
will run up to its maximum speed and the governor will begin to act,
shortening sail before the wind attains this velocity. Therefore, by a
very liberal estimate, the pump will not throw more than double the
quantity that it did in the 8 to 10 mile wind, while the power of the
mill has quadrupled, and is capable of running at least two pumps as
large as the one to which it is attached. As the velocity of the wind
increases, this same proportion of difference in power developed to work
done holds good.
St. Louis is not considered a very windy place, therefore the following
table may be a surprise to some. This table was compiled from the
complete record of the year 1881, as recorded by the anemometer of the
United States Signal Office on the Mutual Life Insurance Building,
corner of Sixth and Locust streets, this city. It gives the number of
hours each month that the wind blew at each velocity, from 6 to 20 miles
per hour during the year; also the maximum velocity attained each month.
_Complete Wind Record at St. Louis for the Year 1881._
_______________________________________________________________________________
|No. |No. |No. |No. |No. |No. |No. |No. |
|hours |hours |hours |hours |hours |hours |hours |hours |Maximum
|wind |wind |wind |wind |wind |wind |wind |wind |velocity
YEAR |blew 6 |blew 8 |blew 10|blew 12|blew 14|blew 16|blew 18|blew 20|during
1881. |miles |miles |miles |miles |miles |miles |miles |miles |each
MONTHS|or over|or over|or over|or over|or over|or over|or over|or over|month.
______|_______|_______|_______|_______|_______|_______|_______|_______|____
|H. M.|H. M.|H. M.|H. M.|H. M.|H. M.| H. M.| H. M.|
Jan. | 545 45| 429 45| 289 00| 198 15| 131 30| 87 15| 56 00| 38 45| 31
Feb. | 619 30| 533 15| 449 15| 374 15| 287 00| 207 15| 151 15| 110 30| 32
March.| 604 15| 534 30| 449 45| 368 45| 296 30| 243 45| 191 00| 158 45| 37
April.| 577 15| 468 45| 342 45| 359 30| 175 00| 121 00| 62 45| 36 00| 28
May. | 553 00| 375 00| 226 15| 138 00| 74 45| 42 30| 23 45| 11 30| 31
June. | 614 15| 463 45| 303 30| 215 15| 123 45| 76 30| 29 45| 17 45| 32
July. | 556 45| 378 00| 228 15| 136 15| 55 30| 22 30| 6 00| 2 30| 22
Aug. | 536 30| 345 00| 176 00| 80 30| 35 45| 22 15| 17 15| 15 00| 34
Sept. | 564 15| 445 45| 326 45| 224 45| 145 30| 96 45| 70 00| 46 45| 30
Oct. | 617 30| 501 45| 368 45| 363 00| 170 00| 93 45| 40 30| 27 45| 27
Nov. | 642 45| 537 30| 428 45| 328 30| 226 00| 151 45| 100 30| 74 00| 30
Dec. | 592 15| 516 30| 390 00| 308 45| 224 45| 167 45| 110 45| 67 00| 30
------+-------+-------+-------+-------+-------+-------+-------+-------+-----
Totals|7,024 |5,529 |3,981 |2,995 |1,946 |1,335 | 868 | 606 | --
| 00| 30| 00| 45| 00| 00| 30| 15|
Max. | | | | | | | | |
for | ----- | ----- | ----- | ----- | ----- | ----- | ----- | ----- | 37
year | | | | | | | | |
______|_______|_______|_______|_______|_______|_______|_______|_______|____
The location of a mill has a great deal to do with the results attained.
Having had charge of the erection of a large number of these mills for
power purposes, I will refer to a few of them in different States,
giving the actual results accomplished, and leaving you to form your own
opinion as to the power developed.
In 1877 a 25-foot diameter mill was erected at Dover, Kansas, a few
miles southwest of Topeka. It was built to do custom flour and feed
grinding, also corn shelling, and is in successful operation at the
present time. We have letters frequently from the owner; one of recent
date states that it has stood all of the "Kansas zephyrs," never having
been damaged as yet. On an average it shells and grinds from 6 to 10
bushels of corn per hour, and runs a 14 inch burr stone, grinding wheat
at the same time. During strong winds it has shelled and ground as high
as 30 bushels of corn per hour. Plate 2 is from a photograph of this
mill and building as it stands. One bevel pinion is all the repairs this
mill has required.
In the spring of 1880 there was erected a 25-foot diameter mill at
Harvard, Clay County, Neb. After this mill had been running nineteen
months, we received the following report from the owner:
"During the nineteen months we have been running the wind mill, it has
cost us nothing for repairs. We run it with a two-hole corn sheller, a
set of 16-inch burr stones, and an elevator. We grind all kinds of feed,
also corn meal and Graham flour. We have ground 8,340 bushels, and would
have ground much more if corn had not been a very poor crop here for the
past two seasons; besides, we have our farm to attend to, and cannot
keep it running all the time that we have wind. We have not run a full
day at any time, but have ground 125 bushels in a day. When the burr is
in good shape we can grind 20 bushels an hour, and shell at the same
time in the average winds that we have. The mill has withstood storms
without number, even one that blew down a house near it, and another
that blew down many smaller mills. It is one of the best investments any
one can make."
The writer saw this mill about sixty days ago, and it is in good shape,
and doing the work as stated. The only repairs that it has required
during four years was one bevel pinion put on this spring.
The owner of a 16-foot diameter mill, erected at Blue Springs. Neb.,
says that "with a fair wind it grinds easily 15 bushels of corn per hour
with a No. 3 grinder, also runs a corn-sheller and pump at the same
time, and that it works smoothly and is entirely self-regulating."
The No. 3 grinder referred to has chilled iron burrs, and requires from
3 to 4 horse-power to grind 15 bushels of corn per hour. Of one of these
16-foot mills that has been running since 1875 in Northern Illinois, the
owner writes: "In windy days I saw cord-wood as fast as the wood can be
handled, doing more work than I used to accomplish with five horses."
The owner of one of these mills, 20 feet in diameter, running in the
southwestern part of this State, writes that he has a corn-sheller and
two iron grinding mills with 8-inch burrs attached to it; also a bolting
device; that this mill is more profitable to him than 80 acres of good
corn land, and that it is easily handled and has never been out of
order. The following report on one of these 16-foot mills, running in
northern Illinois, may be of interest: This mill stands between the
house and barn. A connection is made to a pump in a well-house 25 feet
distant, and is also arranged to operate a churn and washing machine. By
means of sheaves and wire cable, power is transmitted to a circular saw
35 feet distant. In this same manner power is transmitted to the barn
200 feet distant, where connection is made to a thrasher, corn-sheller,
feed-cutter, and fanning-mill. The corn-sheller is a three horse-power,
with fan and sacker attached. Three hundred bushels per day has been
shelled, cleaned, and sacked. The thrashing machine is a two horsepower
with vibrating attachment for separating straw from grain. One man has
thrashed 300 bushels of oats per day, and on windy days says the mill
would run a thrasher of double this capacity. The saw used is 18 inches
diameter, and on windy days saws as much wood as can be done by six
horses working on a sweep power. The owner furnishes the following
approximate cost of mill with the machinery attached and now in use on
his place:
1 16-foot power wind mill, shafting, and tower. $385
1 Two horse thrasher. 70
1 Three horse sheller. 38
1 Feed grinder. 50
1 18-inch saw, frame and arbor. 40
1 Fanning mill. 25
1 Force pump. 27
1 Churn. 5
1 Washing machine. 15
Belting, cables, and pulleys. 45
----
Total. $700
The following facts and figures furnished by the owner will give a fair
idea of the economic value of this system, as compared with the usual
methods of doing the same work. On the farm where it is used, there are
raised annually an average of sixty acres of oats, fifty acres of corn,
twenty acres of rye, ten acres of buckwheat.
Bushels.
The oats average, say 30 bushels per acre. 1,800
Corn " 30 " " 1,500
Rye " 20 " " 400
Buckwheat " 20 " " 200
Grinding for self and others. 1,000
It will cost to thrash this grain, shell the corn, and
grind the feed with steam power. $285
And sawing wood, 121/2 cords. 18
Pumping, one hour per day, 365 days. 36
Churning, half hour per day, 200 days. 10
Washing, half day per week, 26 days. 26
----
Total. $375
This amount is saved, and more too, as one man, by the aid of the wind
mill, will do this work in connection with the chores of the farm, and
save enough in utilizing foul weather to more than offset his extra
labor, cost of oil, etc., for the machinery. The amount saved each year
is just about equal to the cost of a good man. Cost of outfit,
$700--just about equal to the cost of a good man for two years,
consequently, it will pay for itself in two years. Fifteen years is a
fair estimate for the lifetime of mill with ordinary repairs.
The solid-wheel wind mill has never been built larger than 30 feet in
diameter. For mills larger than this, the latest improved American mill
is the "Warwick" pattern.
A 30-foot mill of this pattern, erected in 1880, in northwestern Iowa,
gave the following results, as reported by the owner:
"Attachments as follows: One 22-inch burr; one No. 4 iron feed-mill; one
26-inch circular saw; one two-hole corn-sheller; one grain elevater; a
bolting apparatus for fine meal, buckwheat and graham, all of which are
run at the same time in good winds, except the saw or the iron mill;
they being run from the same pulley can run but one at a time. With all
attached and working up to their full capacity, the sails are often
thrown out of the wind by the governors, which shows an immense power.
The machines are so arranged that I can attach all or separately,
according to the wind. With the burr alone I have ground 500 bushels in
48 consecutive hours, 100 bushels of it being fine meal. I have also
ground 24 full bushels of fine meal for table use in two hours. This
last was my own, consequently was not tolled. This was before I bought
the iron mill, and now I can nearly double that amount. I saw my fire
wood for three fires; all my fence posts, etc. My wood is taken to the
mill from 12 to 15 feet long, and as large as the saw will cut by
turning the stick, consequently the saw requires about the same power as
the burrs. With a good sailing breeze I have all the power I need, and
can run all the machinery with ease. Last winter I ground double the
amount of any water mill in this vicinity. I have no better property
than the mill."
A 40-foot mill, erected at Fowler, Indiana, in 1881, is running the
following machinery:
"I have a universal wood worker, four side, one 34-inch planer, jig saw,
and lathe, also a No. 4 American grinder, and with a good, fair wind I
can run all the machines at one time. I can work about four days and
nights each week. It is easy to control in high winds."
A 60-foot diameter mill of similar pattern was erected in Steel County,
Minnesota, in 1867. The owner gives the following history of this mill:
"I have run this wind flouring mill since 1867 with excellent success.
It runs 3 sets of burrs, one 4 feet, one 31/2 feet, and one 33 inches.
Also 2 smutters, 2 bolts, and all the necessary machinery to make the
mill complete. A 15-mile wind runs everything in good shape. One wind
wheel was broken by a tornado in 1870, and another in 1881 from same
cause. Aside from these two, which cost $250 each, and a month's lost
time, the power did not cost over $10 a year for repairs. In July, 1833,
a cyclone passed over this section, wrecking my will as well as
everything else in its track, and having (out of the profits of the wind
mill) purchased a large water and steam flouring mill here, I last fall
moved the wind mill out to Dakota, where I have it running in
first-class shape and doing a good business. The few tornado wrecks make
me think none the less of wind mills, as my water power has cost me four
times as much in 6 years as the wind power has in 16 years."
There are very few of these large mills in use in this country, but
there are a great many from 14 to 30 feet in diameter in use, and their
numbers are rapidly increasing as their merits become known. The field
for the use of wind mills is almost unlimited, and embraces pumping
water, drainage, irrigation, elevating, grinding, shelling, and cleaning
grain, ginning cotton, sawing wood, churning, running stamp mills, and
charging electrical accumulators. This last may be the solution of the
St. Louis gas question.
In the writer's opinion the settlement of the great tableland lying
between the Mississippi Valley and the Rocky Mountains, and extending
from the Gulf of Mexico to the Red River of the North, would be greatly
retarded, if not entirely impracticable, in large sections where no
water is found at less than 100 to 500 feet below the surface, if it
were not for the American wind mill; large cattle ranges without any
surface water have been made available by the use of wind mills. Water
pumped out of the ground remains about the same temperature during the
year, and is much better for cattle than surface water. It yet remains
in the future to determine what the wind mill will not do with the
improvements that are being made from to time.
* * * * *
THE PNEUMATIC DYNAMITE GUN.
It is here shown as mounted on a torpedo launch and ready for action.
The shell or projectile is fired by compressed air, admitted from an air
reservoir underneath by a simple pressure of the gunner's finger over
the valve. The air passes up through the center of the base, the pipe
connecting with one of the hollow trunnions. The valve is a continuation
of the breech of the gun. The smaller cuts illustrate Lieutenant
Zalinski's plan for mounting the gun on each side of the launch, by
which plan the gun after being charged may have the breech containing
the dynamite depressed, and protected from shots of the enemy by its
complete immersion alongside the launch; and, if necessary, may be
discharged from this protected position. The gun is a seamless brass
tube of about forty feet in length, manipulated by the artillerist in
the manner of an ordinary cannon. Its noiseless discharge sends the
missile with great force, conveying the powerful explosive within it,
which is itself discharged internally upon contact with the deck of a
vessel or other object upon which it strikes, through the explosion of a
percussion fuse in the point of the projectile. A great degree of
accuracy has been obtained by the peculiar form of the projectile.
[Illustration: PNEUMATIC DYNAMITE GUN TORPEDO VESSEL.]
The projectile consists of a thin metal tube, into which the charge is
inserted, and a wooden sabot which closes it at the rear and flares out
until its diameter equals that of the bore of the gun. The forward end
of the tube is pointed with some soft material, in which is embedded the
firing pin, a conical cap closing the end. A cushion of air is
interposed at the rear end of the dynamite charge, to lessen the shock
of the discharge and prevent explosion, until the impact of the
projectile forces the firing pin in upon the dynamite and explodes it.
Many charges have been successfully fired at Fort Hamilton, N.Y. As the
center of gravity is forward of the center of figure in the projectile,
a side wind acting upon the lighter rear part would tend to turn the
head into the wind and thus keep it in the line of its trajectory. A
range of 11/4 miles has been attained with the two inch gun, with a
pressure of 420 lb. to the square inch, and one of three miles is hoped
for with the larger gun and a pressure of 2,000 lb.
* * * * *
ROPE PULLEY FRICTION BRAKE.
A novel device in connection with rope pulley blocks is illustrated in
the annexed engravings, the object of the appliance being to render it
possible to leave a weight suspended from a block without making the
tail of the rope fast to some neighboring object. By this arrangement
the danger of the rope slipping loose is avoided, and absolute security
is attained, without the necessity of lowering the weight to the ground.
The device itself is a friction brake, constructed in the form of a clip
with holes in it for the three ropes to pass through. It is made to span
the block, and is secured partly by the pin or bolt upon which the
sheaves run, and partly by the bottom bolt, which unites the cheeks of
the block. Thus the brake is readily attachable to existing blocks. The
inner half of the clip or brake is fixed solidly to the block, while the
outer half is carried by two screws, geared together by spur-wheels, and
so cut that although rotating in opposite directions, their movements
are equal and similar. One of the screws carries a light rope-wheel, by
which it can be rotated, the motion being communicated to the second
screw by the toothed wheels. When the wheel is rotated in the right
direction the loose half of the clip is forced toward the other half,
and grips the ropes passing between the two so powerfully that any
weight the blocks are capable of lifting is instantly made secure, and
is held until the brake is released.
A light spiral spring is placed on each of the screws, in order to free
the brake from the rope the moment the pressure is released. The hand
rope has a turn and a half round the pulley, and this obviates the need
of holding both ends of it, and thus leaves one hand free to guide the
descending weight, or to hold the rope of the pulley blocks.
_Engineering_ says these brakes are very useful in raising heavy
weights, as the lift can be secured at each pull, allowing the men to
move hands for another pull, and as they are made very light they do not
cause any inconvenience in moving or carrying the blocks about.
Manufactured by Andrew Bell & Co., Manchester.
* * * * *
WIRE ROPE TOWAGE.
We have from time to time given accounts in this journal of the system
of towage by hauling on a submerged wire rope, first experimented upon
by Baron O. De Mesnil and Mr. Max Eyth. On the river Rhine the system
has been for many years in successful operation; it has also been used
for several years on the Erie Canal in this State. We publish from
_Engineering_ a view of one of the wire rope tug boats of the latest
pattern adopted for use on the Rhine.
The Cologne Central Towing Company (Central Actien-Gesellschaft fuer
Tauerei und Schleppschifffahrt), by whom the wire rope towage on the
Rhine is now carried on, was formed in 1876, by an amalgamation of the
Ruehrorter und Mulheimer Dampfschleppshifffahrt Gesellschaft and the
Central Actien-Gesellschaft fur Tauerei, and in 1877 it owned eight wire
rope tugs (which it still owns) and seventeen paddle tugs. The company
so arranges its work that the wire rope tugs do the haulage up the rapid
portion of the Rhine, from Bonn to Bingen, while the paddle tugs are
employed on the quieter portion of the river extending from Rotterdam to
Bonn, and from Bingen to Mannheim.
[Illustration: ROPE PULLEY FRICTION BRAKE.]
The leading dimensions of the eight wire rope tugs now worked by the
company are as follows:
Tugs No. I. to Tugs No. V. to
IV. VIII.
Meters. ft. in. Meters. ft. in.
Length between
perpendiculars 39 = 126 0 42 = 137 10
Length over all 42.75 = 140 3 45.75 = 150 1
Extreme breadth 7.2 = 28 8 7.5 = 24 5
Height of sides 2.38 = 7 11 2.38 = 7 11
Depth of keel 0.12 = 0 5 0.15 = 0 6
All the boats are fitted with twin screws, 1.2 meters (3 feet 111/4
inches) in diameter, these being used on the downstream journey, and
also for assisting in steering while passing awkward places during the
journey up stream. They are also provided with water ballast tanks, and
under ordinary circumstances they have a draught of 1.3 to 1.4 meters (4
feet 3 inches to 4 feet 7 inches), this draught being necessary to give
proper immersion to the screws. When the water in the Rhine is very low,
however, the water ballast is pumped out and the tugs are then run with
a draught of 1 meter (3 feet 3 3/8 inches), it being thus possible to
keep them at work when all other towing steamers on the Rhine are
stopped. This happened in the spring of 1882.
Referring to our engraving, it will be seen that the wire rope rising
from the bed of the river passes first over a large guide pulley, the
axis of which is carried by a substantial wrought iron swinging bracket,
this bracket being so pivoted that while the pulley is free to swing
into the line on which the rope is approached by the vessel, yet the
rope on leaving the pulley is delivered in a line which is tangential to
a second guide pulley placed further aft and at a lower level. This last
named guide pulley does not swing, and from it the rope is delivered to
the clip drum, over which it passes. From the clip drum the rope passes
under a third guide pulley; this pulley swings on a bracket having a
vertical axis. This third pulley projects down below the keel of the tug
boat, so that the rope on leaving it can pass under the vessel without
fouling. Suitable recesses are formed in the side of the tug boat to
accommodate the swinging pulleys, while the bow of the boat is sloped
downward nearly to the water line, as shown, so as to allow of the
rising part of the rope swinging over it if necessary.
The hauling gear with which the tug is fitted consists of a pair of
condensing engines with cylinders 14.17 inches in diameter and 23.62
inches stroke, the crankshaft carrying a pinion which gears into a spur
wheel on an intermediate shaft, this shaft again carrying a pinion which
gears into a large spur wheel fixed on the shaft which carries the clip
drum. In the arrangement of hauling gear above described the ratio of
the gear is 1:8.44, in the case of tugs Nos. I. to IV.; while in tugs
Nos. V. to VIII. the proportion has been made 1:11.82. In tugs I. to IV.
the diameter of the clip drum is 2.743 meters (9 feet), while in the
remaining tugs it is 3.056 meters (10 feet).
From some interesting data which have been placed at our disposal by Mr.
Thomas Schwarz, the manager of the Central Actien-Gesellschaft fur
Tauerei und Schleppschifffahrt, we learn that in the tugs Nos. I. to IV.
the hauling machine develops on an average 150 indicated horse, while in
the tugs No. V. to VIII. the power developed averages 180 indicated
horse power. The tugs forming the first named group haul on an average
2,200 tons of cargo, contained in four wooden barges, at a speed of 41/2
kilometers (2.8 miles) per hour, against a stream running at the rate of
61/2 kilometers (4.05 miles) per hour, while the tugs Nos. V. to VIII.
will take a load of 2,600 tons of cargo in the same number of wooden
barges at the same speed and against the same current. In iron barges,
about one and a half times the quantity of useful load can be drawn by a
slightly less expenditure of power.
The average consumption of coal per hour is, for tugs Nos. I. to IV., 5
cwt, and for tugs Nos. V. to VIII., 6 cwt.; and of this fuel a small
fraction (about one-sixth) is consumed by the occasional working of the
screw propellers at sharp bends. The fuel consumption of the wire rope
tugs contrasts most favorably with that of the paddle and screw tugs
employed on the Rhine, the best paddle tugs (with compound engines,
patent wheels, etc.) burning three and a half times as much; the older
paddle tugs (with low pressure non-compound engines), four and a half
times as much; and the latest screw tugs, two and a half times as much
coal as the wire rope tugs when doing the same work under the same
circumstances. The screw tugs just mentioned have a draught of 21/2 meters
(8 feet 21/2 inches), and are fitted with engines of 560 indicated horse
power.
During the years 1879, 1880, and 1881, the company had in use fourteen
paddle tugs and ten eight-wire rope tugs, both classes being--owing to
the state of trade--about equally short of work. The results of the
working during these years were as follows:
================================================================
| | Freight | Cost of | Degree
| | hauled | haulage in | of
Class of tugs. | Year. | in | pence per | occupation.
| | ton-miles. | ton-mile. |
----------------------------------------------------------------
Paddle | 1879 | 31,862,858 | 0.1272 | 0.686
" | 1880 | 31,467,422 | 0.1305 | 0.638
" | 1881 | 28,627,049 | 0.1245 | 0.537
Wire Rope | 1879 | 15,407,935 | 0.1167 | 0.614
" | 1880 | 17,289,706 | 0.1056 | 0.615
" | 1881 | 17,593,181 | 0.0893 | 0.536
================================================================
The last column in the above tabular statement, headed "Degree of
Occupation," may require some explanation. It is calculated on the
assumption that a tug could do 3,000 hours of work per annum, and this
is taken as the unit, the time of actual haulage being counted as full
time, and of stoppages as half time. The expenses included in the
statement of cost of haulage include all working expenses, repairs,
general management, and depreciation. The accounts for 1882, which are
not completely available at the time we are writing, show much better
results than above recorded, there being a considerable reduction of
cost, while the freight hauled amounted to a total of 54,921,965
ton-miles.
[Illustration: WIRE ROPE TUG BOAT, RIVER RHINE.]
As regards the wear of the rope, we may state that the relaying of the
first rope between St. Goar and Bingen was taken in hand in September,
1879, while that between Obercassel and Bingen was partially renewed the
same year, the renewal being completed in May, 1880, after the rope had
been in use since the beginning of 1876. The second rope between Bonn
and Bingen, a length of 743/4 miles, is of galvanized wire, has now been
23/4 years in use, during which time there have been but three fractures.
The first rope laid was not galvanized, and it suffered nine fractures
during the first three years of its use. The first rope, we may mention,
was laid in lengths of about a mile spliced together, while the present
rope was supplied in long lengths of 71/2 miles each, so that the number
of splices is greatly reduced. According to the report of the company
for the year 1880, the old rope when raised realizes about 16 per cent.
of its original value, and allowing for this, it is calculated that an
allowance of 18.7 per cent. per annum will cover the cost of rope
depreciation and renewals. Altogether the results obtained on the Rhine
show that in a rapid stream the economic performances of wire rope tugs
compare most favorably with those of either paddle or screw tug boats,
the more rapid the current to be contended against the greater being the
advantage of the wire rope haulage.
* * * * *
IMPROVED HAY-ROPE MACHINE.
Hay-ropes are used for many purposes, their principal use being in the
foundry for core-making; but they also find a large application for
packing ironmongery and furniture. The inventor is James Pollard, of the
Atlas Foundry, Burnley.
[Illustration: HAY ROPE MACHINE.]
The chief part of the mechanism is carried in an open frame, having
journals attached to its two ends, which revolve in bearings. The frame
is driven by the rope pulley. The journal at the left hand is hollow;
the pinion upon it is stationary, being fixed to the bracket of bearing.
The pinion gearing into it is therefore revolved by the revolution of
the frame, and through the medium of bevel wheels actuates a transverse
shaft, parallel to which rollers, and driven by wheels off it, is a
double screw, which traverses a "builder" to and fro across the width of
frame. The builder is merely the eye through which the band passes, and
its office is to lay the band properly on the bobbin. The latter is
turned to coil on the band by a pitch chain from the builder screw, the
motion being given through a friction clutch, to allow for slip as the
bobbin or coil gets larger, for obviously the bobbin as it gets larger
is not required to turn so fast to coil up the band produced as when it
is smaller. If the action is studied, it will be seen that the twist is
put in between the bobbin and the hollow journal, and every revolution
of the frame puts in one turn for the twist. The hay is fed to the
machine through the hollow journal already mentioned. By suitably
proportioning the speed of feed-rollers and the revolutions of the
frame, which is easily accomplished by varying the wheels on the left
hand of frame, bands of any degree of hardness or softness may be
produced. The machine appears to be simple and not liable to get
deranged. It may be after a little practice attended to by a laborer,
and is claimed by its maker to be able to produce 400 yards of band per
hour. The frame makes about 180 revolutions per minute, that is, this is
the number of turns put into the twist in this time. The machine can
make a bundle about 200 yards long, which can be removed off the bobbin
without unwinding with the greatest facility.--_Mech. World._
* * * * *
THE ANGLESEA BRIDGE, CORK.
The river Lee flows through the city of Cork in two branches, which
diverge just above the city, and are reunited at the Custom House, the
central portion of the city being situated upon an island between the
two arms of the river, both of which are navigable for a short distance
above the Custom House, and are lined with quays on each side for the
accommodation of the shipping of the port.
The Anglesea bridge crosses the south arm of the river about a quarter
of a mile above its junction with the northern branch, and forms the
chief line of communication from the northern and central portions of
the city to the railway termini and deep-water quays on the southern
side of the river.
[Illustration: THE NEW ANGLESEA BRIDGE, CORK.]
The new swing bridge occupies the site of an older structure which had
been found inadequate to the requirements of the heavy and increasing
traffic, and the foundations of the old piers having fallen into an
insecure condition, the construction of a new opening bridge was taken
in hand jointly by the Corporation and Harbor Commissioners of Cork.
The new bridge, which has recently been completed, is of a somewhat
novel design, and the arrangement of the swing-span in particular
presents some original and interesting features, which appear to have
been dictated by a careful consideration of the existing local
conditions and requirements.
On each side of the river, both above and below the bridge, the quays
are ordinarily lined with vessels berthed alongside each of the quays,
and as the river is rather narrow at this point, the line of fairway for
vessels passing through the bridge is confined nearly to the center of
the river. This consideration, together with some others connected with
the proposed future deepening of the fairway, rendered it very desirable
to locate the opening span nearly in the center of the river, as shown
in the general plan of the situation, which we publish herewith. At the
same time it was necessary to avoid any encroachment upon the width of
the existing quays, which form important lines of communication for
vehicular and passenger traffic along each side of the river, and to and
from the railway stations. Again, it was necessary to preserve the full
existing width of waterway in the river itself, which is sometimes
subjected to heavy floods.
These considerations evidently precluded the construction of a central
pier and double-armed swing bridge, and on the other hand they also
precluded the construction of any solid masonry substructure for the
turntable, either upon the quay or projected into the river. To meet
these several conditions the bridge has been designed in the form of a
three-span bridge, that is to say, it is only supported by the two
abutments and two intermediate piers, each consisting of a pair of
cast-iron cylinders or columns, as shown by the dotted circles upon the
general plan.
The central opening is that which serves for the passage of vessels. The
swing bridge extends over two openings, or from the north abutment to
the southern pier, its center of revolution being situated over the
center of the northern span, and revolves upon a turntable, which is
carried upon a lower platform or frame of girders extending across the
northern span of the bridge. The southern opening is spanned by an
ordinary pair of lattice girders in line with the girders and
superstructure of the swing bridge.
We propose at an early date to publish further details of this bridge,
and the hydraulic machinery by which it is worked.
We present a perspective view of the bridge as seen from the entrance to
the exhibition building, which is situated in close proximity to the
southern end of the bridge.--_Engineering_.
* * * * *
PORTABLE RAILWAYS.
[Footnote: Paper read before the Institution of Mechanical Engineers.]
By M. DECAUVILLE, Aine, of Petit-Bourg (Seine and Oise), France.
Narrow gauge railways have been known for a very long time in Great
Britain. The most familiar lines of this description are in Wales, and
it is enough to instance the Festiniog Railway (2 feet gauge), which has
been used for the carriage of passengers and goods for nearly half a
century. The prosperous condition of this railway, which has been so
successfully improved by Mr. James Spooner and his son, Mr. Charles
Spooner, affords sufficient proof that narrow gauge railways are not
only of great utility, but may be also very remunerative.
In Wales the first narrow gauge railway dates from 1832. It was
constructed merely for the carriage of slates from Festiniog to
Port-Madoc, and some years later another was built from the slate
quarries at Penrhyn to the port of Bangor. As the tract of country
traversed by the railways became richer by degrees, the idea was
conceived of substituting locomotives for horses, and of adapting the
line to the carriage of goods of all sorts, and finally of passengers
also.
But these railways, although very economical, are at the same time very
complicated in construction. Their arrangements are based upon the same
principles as railways of the ordinary gauge, and are not by any means
capable of being adapted to agriculture, to public works, or to any
other purpose where the tracks are constantly liable to removal. These
permanent narrow gauge lines, the laying of which demands the service of
engineers, and the maintenance of which entails considerable expense,
suggested to M. Decauville, Aine, farmer and distiller at Petit-Bourg,
near Paris, the idea of forming a system of railways composed entirely
of metal, and capable of being readily laid. Cultivating one of the
largest farms in the neighborhood of Paris, he contemplated at first
nothing further than a farm railroad; and he contrived an extremely
portable plant, adapted for clearing the land of beetroot, for spreading
manure, and for the other needs of his farm.
From the beginning in his first railroads, the use of timber materials
was rigidly rejected by him; and all parts, whether the straight or
curved rails, crossings, turntables, etc., were formed of a single
piece, and did not require any special workman to lay them down. By
degrees he developed his system, and erected special workshops for the
construction of his portable plant; making use of his farm, and some
quarries of which he is possessed in the neighborhood, as experimental
areas. At the present time this system of portable railways serves all
the purposes of agriculture, of commerce, of manufactures, and even
those of war.
Within so limited a space it would be impossible to give a detailed
description of the rails and fastenings used in all these different
modes of application. The object of this paper is rather to direct the
attention of mechanical engineers to the various uses to which narrow
gauge portable railways may be put, to the important saving of labor
which is effected by their adoption, and to the ease with which they are
worked.
The success of the Decauville railway has been so rapid and so great
that many inventors have entered the same field, but they have almost
all formed the idea of constructing the portable track with detachable
sleepers. There are thus, at present, two systems of portable tracks:
those in which the sleepers are capable of being detached, and those in
which they are not so capable.
The portable track of the Decauville system is not capable of so coming
apart. The steel rails and sleepers are riveted together, and form only
one piece. The chief advantage of these railways is their great
firmness; besides this, since the line has only to be laid on the
surface just as it stands, there are not those costs of maintenance
which become unavoidable with lines of which the sleepers are fixed by
means of bolts, clamps, or other adjuncts, only too liable to be lost.
Moreover, tracks which are not capable of separation are lighter and
therefore more portable than those in which the sleepers are detachable.
With regard to sleepers, a distinction must be drawn between those which
project beyond the rails and those which do not so project. M.
Decauville has adopted the latter system, because it offers sufficient
strength, while the lines are lighter and less cumbersome. Where at
first he used flat iron sleepers, he now fits his lines with dished
steel sleepers, in accordance with Figs. 1 and 2.
[Illustration: Fig. 1. Fig. 2.]
This sleeper presents very great stiffness, at the same time preserving
its lightness; and the feature which specially distinguishes this
railway from others of the same class is not only its extreme strength,
but above all its solidity, which results from its bearing equally upon
the ground by means of the rail base and of the sleepers.
In special cases, M. Decauville provides also railroads with projecting
sleepers, whether of flat steel beaten out and rounded, or of channel
iron; but the sleeper and the rail are always inseparable, so as not to
lessen the strength, and also to facilitate the laying of the line. If
the ground is too soft, the railway is supported by bowl sleepers of
dished steel, Figs. 3 and 4, especially at the curves; but the necessity
for using these is but seldom experienced. The sleepers are riveted
cold. The rivets are of soft steel, and the pressure with which this
riveting is effected is so intense that the sleepers cannot be separated
from the rails, even after cutting off both heads of the rivets, unless
by heavy blows of the hammer, the rivets being driven so thoroughly into
the holes made in the rails and sleepers that they fill them up
completely.
The jointing of the rails is excessively simple. The rail to the right
hand is furnished with two fish-plates; that to the left with a small
steel plate riveted underneath the rail and projecting 11/4 in. beyond it.
It is only necessary to lay the lengths end to end with one another,
making the rail which is furnished with the small plate lie between the
two fish-plates, and the junction can at once be effected by fish-bolts.
A single fish-bolt, passing through the holes in the fish-plates, and
through an oval hole in the rail end, is sufficient for the purpose.
With this description of railway it does not matter whether the curves
are to the right or to the left. The pair of rails are curved to a
suitable radius, and can only need turning end for end to form a curve
in the direction required. The rails weigh 9 lb., 14 lb., 19 lb., and 24
lb. per running yard, and are very similar to the rails used on the main
railways of France, except that their base has a proportionally greater
width. As to the strength of the rail, it is much greater in proportion
to the load than would at first sight be thought; all narrow-gauge
railways being formed on the principle of distributing the load over a
large number of axles, and so reducing the amount on each wheel. For
instance, the 9 lb. rail used for the portable railway easily bears a
weight of half a ton for each pair of wheels.
The distance between the rails differs according to the purpose for
which they are intended. The most usual gauges are 16in., 20 in., and
24in. The line of 16 in. gauge, with 9 lb. rails, although extremely
light, is used very successfully in farming, and in the interior of
workshops.
[Illustration: Fig. 3. Fig. 4. Fig. 5.]
A length of 16 ft. 5 in. of 9 lb. steel rail, to 16 in. gauge, with
sleepers, etc., scarcely weighs more than 1 cwt., and may therefore be
readily carried by a man placing himself in the middle and taking a rail
in each hand.
Those members of the Institution who recently visited the new port of
Antwerp will recollect having seen there the portable railway which
Messrs. Couvreux and Hersetit had in use; and as it was these works at
the port of Antwerp that gave rise to the idea of this paper, it will be
well to begin with a description of this style of contractor's plant.
The earth in such works may be shifted by hand, horsepower, or
locomotive. For small works the railway of 16 in. gauge, with the 9 lb.
rails, is commonly used, and the trucks carry double equilibrium
tipping-boxes, containing 9 to 11 cubic feet. These wagons, having
tipping-boxes without any mechanical appliances, are very serviceable;
since the box, having neither door nor hinge, is not liable to need
repairs.
This box keeps perfectly in equilibrium upon the most broken up roads.
To tip it up to the right or the left, it must simply be pushed from the
opposite side, and the contents are at once emptied clean out. In order
that the bodies of the wagons may not touch at the top, when several are
coupled together, each end of the wagon is furnished with a buffer,
composed of a flat iron bar cranked, and furnished with a hanging hook.
Plant of this description is now being used in an important English
undertaking at the port of Newhaven, where it is employed not only on
the earthworks, but also for transporting the concrete manufactured with
Mr. Carey's special concrete machine.
These little wagons, of from 9 to 11 cubic feet capacity, run along with
the greatest ease, and a lad could propel one of them with its load for
300 yards at a cost of 3d. per cube yard. In earthworks the saving over
the wheel-barrow is 80 per cent., for the cost of wagons propelled by
hand comes to 0.1d. per cube yard, carried 10 yards, and to go this
distance with a barrow costs 1/2d. A horse draws without difficulty,
walking by the side of the line, a train of from eight to ten trucks on
the level, or five on an incline of 7 per cent. (1 in 14).
One mile of this railway, 16 in. gauge and 9 lb. steel rail, with
sixteen wagons, each having a double equilibrium tipping box containing
11 cubic feet, and all accessories, represents a weight of 20 tons--a
very light weight, if it is considered that all the materials are
entirely of metal. Its net cost price per mile is 450_l_., the wagons
included.
Large contracts for earthwork with horse haulage are carried on to the
greatest advantage with the railway of 20 in. gauge and 14 lb. rails.
The length of 16 ft. 5 in. of this railway weighs 170 lb., and so can
easily be carried by two men, one placing himself at each end. The
wagons most in use for these works are those with double equilibrium
tipping boxes, holding 18 cubic feet. These are at present employed in
one of the greatest undertakings of the age, namely, the cutting of the
Panama Canal, where there are used upward of 2,700 such wagons, and more
than 35 miles of track.
A mile of these rails of 20 in. gauge with 14 lb. rails, together with
sixteen wagons of 18 cubic feet capacity, with appurtenances, costs
about 660_1_., and represents a total weight of 33 tons.
This description of material is used for all contracts exceeding 20,000
cubic yards.
A very curious and interesting use of the narrow-gauge line, and the
wagons with double equilibrium tipping-box, was made by the Societe des
Chemins de Fer Sous-Marins on the proposed tunnel between France and
England. The line used is that of 16 in. gauge, with 9 lb. rails.
The first level of the tunnel, which was constructed by means of a
special machine by Colonel Beaumont, had only a diameter of 2.13 m. (7
ft.); the tipping boxes have therefore a breadth of only 2 ft., and
contain 71/4 cubic feet. The boxes are perfectly balanced, and are most
easily emptied. The wagons run on two lines, the one being for the
loaded trains, and the other for the empty trains.
The engineers and inspectors, in the discharge of their duties, make use
of the Liliputian carriages. The feet of the travelers go between the
wheels, and are nearly on a level with the rails; nevertheless, they are
tolerably comfortable. They are certainly the smallest carriages for
passengers that have ever been built; and the builder even prophesies
that these will be the first to enter into England through the Channel
Tunnel.
One of the most important uses to which a narrow gauge line can be put
is that of a military railway. The Dutch, Russian, and French
Governments have tried it for the transporting of provisions, of war
material, and of the wounded in their recent campaigns. In Sumatra, in
Turkestan, and in Tunis these military railroads have excited much
interest, and have so fully established their value that this paper may
confine itself to a short description.
The campaign of the Russians against the Turcomans presented two great
difficulties; these were the questions of crossing districts in which
water was extremely scarce or failed entirely, and of victualing the
expeditionary forces. This latter object was completely effected by
means of 67 miles of railway, 20 in. gauge, 14 lb. steel rails, with 500
carriages for food, water, and passengers. The rails were laid simply on
the sand, so that small locomotives could not be used, and were obliged
to be replaced by Kirghiz horses, which drew with ease from 1,800 lb. to
2,200 lb. weight for 25 miles per day.
In the Tunisian war this railroad of 20 in. gauge, 14 lb. rail, was
replaced by that of two ft. gauge, with 14 lb. and 19 lb. rails. There
were quite as great difficulties as in the Turcoman campaign, and the
country to be crossed was entirely unknown. The observations made before
the war spoke of a flat and sandy country. In reality a more uneven
country could not be imagined; alternating slopes of about 1 in 10
continually succeeded each other; and before reaching Kairouan 71/2 miles
of swamp had to be crossed. Nevertheless the horses harnessed to the
railway carriages did on an average twelve to seventeen times the work
of those working ordinary carriages. In that campaign also, on account
of the steep ascents, the use of locomotives had to be given up. The
track served not only for the conveying of victuals, war material, and
cannon, but also of the wounded; and a large number of the survivors of
this campaign owe their lives to this railway, which supplied the means
of their speedy removal without great suffering from the temporary
hospitals, and of carrying the wounded to places where more care could
be bestowed upon them.
The carriages which did duty in this campaign are wagons with a platform
entirely of metal, resting upon eight wheels. The platform is 13 ft. 1
in. in length, and 3 ft. 11 in. in width. The total length with buffers
is 14 ft. 9 in. This carriage may be at will turned into a goods wagon
or a passenger carriage for sixteen persons, with seats back to back, or
an ambulance wagon for eight wounded persons.
For the transport of cannon the French military engineers have adopted
small trucks. A complete equipage, capable of carrying guns weighing
from 3 to 9 tons, is composed of trucks with two or three axles, each
being fitted with a pivot support, by means of which it is made possible
to turn the trucks, with the heaviest pieces of ordnance, on turntables,
and to push them forward without going off the rails at the curves.
The trucks which have been adopted for the service of the new forts in
Paris are drawn by six men, three of whom are stationed at each end of
the gun, and these are capable of moving with the greatest ease guns
weighing 9 tons.
The narrow-gauge railway was tested during the war in Tunis more than in
any preceding campaign, and the military authorities decided, after
peace had been restored in that country, to continue maintaining the
narrow-gauge railways permanently; this is a satisfactory proof of their
having rendered good service. The line from Sousse to Kairouan is still
open to regular traffic. In January, 1883, an express was established,
which leaves Sousse every morning and arrives at Kairouan--a distance of
forty miles--in five hours, by means of regularly organized relays. The
number of carriages and trucks for the transport of passengers and goods
is 118.
The success thus attained by the narrow-gauge line goes far to prove how
unfounded is the judgment pronounced by those who hold that light
railways will never suffice for continuous traffic. These opinions are
based on certain cases in the colonies, where it was thought fit to
adopt a light rail weighing about 18 lb. to 27 lb. per yard, and keeping
the old normal gauge. It is nevertheless evident that it is impossible
to construct cheap railways on the normal gauge system, as the
maintenance of such would-be light railways is in proportion far more
costly than that of standard railways.
The narrow gauge is entirely in its right place in countries where, as
notably in the case of the colonies, the traffic is not sufficiently
extensive to warrant the capitalization of the expenses of construction
of a normal gauge railway.
Quite recently the Eastern Railway Company of the province of Buenos
Ayres have adopted the narrow gauge for connecting two of their
stations, the gauge being 24 in. and the weight of the rails 19 lb. per
yard. This company have constructed altogether six miles of narrow-gauge
road, with a rolling stock of thirty passenger carriages and goods
trucks and two engines, at a net cost price of 7,500l., the engines
included. This line works as regularly as the main line with which it is
connected. The composite carriages in use leave nothing to be desired
with regard to their appearance and the comforts they offer. Third-class
carriages, covered and open, and covered goods wagons, are also
employed.
All these carriages are constructed according to the model of those of
the Festiniog Railway. The engines weigh 4 tons, and run at 121/2 miles
per hour for express trains with a live load of 16 tons; while for goods
trains carrying 35 tons the rate is 71/2 miles an hour.
Another purpose for which the narrow-gauge road is of the highest
importance in colonial commerce is the transport of sugar cane. There
are two systems in use for the service of sugar plantations:
1. Traction by horses, mules, or oxen.
2. Traction by steam-engine.
In the former case, the narrow gauge, 20 in. with 14 lb. rails, is used,
with platform trucks and iron baskets 3 ft. 3 in. long.
The use of these wagons is particularly advantageous for clearing away
the sugar cane from the fields, because, as the crop to be carried off
is followed by another harvest, it is important to prevent the
destructive action of the wheels of heavily laden wagons. The baskets
may be made to contain as much as 1,300 lb. of cane for animal traction,
and 2,000 lb. for steam traction. In those colonies where the cane is
not cut up into pieces, long platform wagons are used entirely made of
metal, and on eight wheels. When the traction is effected by horses or
mules, a chain 141/2 ft. long is used, and the animals are driven
alongside the road. Oxen are harnessed to a yoke, longer by 20 in. to 24
in. than the ordinary yoke, and they are driven along on each side of
the road.
On plantations where it is desirable to have passenger carriages, or
where it is to be foreseen that the narrow-gauge line maybe required for
the regular transport of passengers and goods, the 20 in. line is
replaced by one of 24 in.
The transport of the refuse of sugar cane is effected by means of
tilting basket carts; the lower part of which consists of plate iron as
in earthwork wagons, while the upper part consists of an open grating,
offering thus a very great holding capacity without being excessively
heavy. The content of these wagons is 90 cubic feet (2,500 liters). To
use it for the transport of earth, sand, or rubbish, the grating has
merely to be taken off. In the case of the transport of sugar cane
having to be effected by steam power, the most suitable width of road is
24 in., with 19 lb. rails; and this line should be laid down and
ballasted most carefully. The cost of one mile of the 20 in. gauge road,
with 14 lb. rails, thirty basket wagons, and accessories for the
transport of sugar cane, is 700l., and the total weight of this plant
amounts to 35 tons.
Owing to the great lightness of the portable railways, and the facility
with which they can be worked, the attention of explorers has repeatedly
been attracted by them. The expedition of the Ogowe in October, 1880,
that of the Upper Congo in November, 1881, and the Congo mission under
Savorgnan de Brazza, have all made use of the Decauville narrow-gauge
railway system.
During these expeditions to Central Africa, one of the greatest
obstacles to be surmounted was the transport of boats where the river
ceased to be navigable; for it was then necessary to employ a great
number of negroes for carrying both the boats and the luggage. The
explorers were, more or less, left to the mercy of the natives, and but
very slow progress could be made.
On returning from one of these expeditions in Africa, Dr. Balay and M.
Mizon conceived the idea of applying to M. Decauville for advice as to
whether the narrow-gauge line might not be profitably adapted for the
expedition. M. Decauville proposed to them to transport their boats
without taking them to pieces, or unloading them, by placing them on two
pivot trollies, in the same manner as the guns are transported in
fortifications and in the field. The first experiments were made at
Petit-Bourg with a pleasure yacht. The hull, weighing 4 tons, was placed
on two gun trollies, and was moved about easily across country by means
of a portable line of 20 in. gauge, with 14 lb. rails. The length of the
hull was about 45 ft., depth 6 ft. 7 in., and breadth of beam 8 ft. 2
in., that is to say, five times the width of the narrow-gauge, and
notwithstanding all this the wheels never came off the line. The
sections of line were taken up and replaced as the boat advanced, and a
speed of 1,100 yards per hour was attained. Dr. Balay and M. Mizon
declared that the result obtained exceeded by far their most sanguine
hopes, because during their last voyage, the passage of the rapids had
sometimes required a whole week for 1,100 yards (1 kilometer), and they
considered themselves very lucky indeed if they could attain a speed of
one kilometer per day. The same narrow gauge system has since been three
times adopted by African explorers, on which occasions it was found that
the 20 in. line, with 9 lb. or 14 lb. rails, was the most suitable for
scientific expeditions of this nature.
The trucks used are of the kind usually employed for military purposes,
with wheels, axles, and pivot bearings of steel; on being dismounted the
bodies of the two trucks form a chest, which is bolted together and
contains the wheels, axles, and other accessories. The total weight of
the 135 yards of road used by Dr. Balay and M. Mizon during their first
voyage was 2,900 lb., and the wagons weighed 5,000 lb. Hence the
expedition had to carry a supplementary weight of 31/2 tons; but at any
given moment the material forming this burden became the means of
transporting, in its turn, seven boats, representing a total weight of
20 tons.
It is impossible to enumerate in this paper all the various kinds of
wagons and trucks suitable for the service of iron works, shipyards,
mines, quarries, forests, and many other kinds of works; and we
therefore limit ourselves to mentioning only a few instances which
suffice to show that the narrow gauge can be applied to works of the
most varied nature and under the most adverse circumstances possible.
It therefore only remains to mention the various accessories which have
been invented for the purpose of completing the system. They consist of
off-railers, crossings, turntables, etc.
The off railer is used for establishing a portable line, at any point,
diverging to the right or left of a permanent line, and for transferring
traffic to it without interruption. It consists of a miniature inclined
plane, of the same height at one end as the rail, tapering off regularly
by degrees toward the other end. It is only necessary to place the
off-railer (which, like all the lengths of rail of this system, forms
but one piece with its sleepers and fish-plates) on the fixed line,
adding a curve in the direction it is intended to go, and push the
wagons on to the off-railer, when they will gradually leave the fixed
line and pass on the new track.
The switches consist of a rail-end 49 in. in length, which serves as a
movable tongue, placed in front of a complete crossing, the rails of
which have a radius of 4, 6, or 8 meters; a push with the foot suffices
to alter the switch. There are four different models of crossings
constructed for each radius, viz.:
1. For two tracks with symmetrical divergence.
2. For a curve to the right and a straight track.
3. For a curve to the left and a straight track.
4. For a meeting of three tracks.
When a fixed line is used, it is better to replace the movable switch by
a fixed cast-iron switch, and to let the workmen who drive the wagon
push it in the direction required. Planed switch tongues are also used,
having the shape of those employed on the normal tracks, especially for
the passage of small engines; the switches are, in this case, completed
by the application of a hand lever.
The portable turntable consists of two faced plates laid over the other,
one of thick sheet iron, and the other of cast iron. The sheet-iron
plate is fitted with a pivot, around which the cast iron one is made to
revolve; these plates may either be smooth, or grooved for the wheels.
The former are used chiefly when it is required to turn wagons or trucks
of light burden, or, in the case of earthworks, for trucks of moderate
weight. These plates are quite portable; their weight for the 16 in.
gauge does not exceed 200 lb. For engineering works a turntable plate
with variable width of track has been designed, admitting of different
tracks being used over the same turntable.
When turntables are required for permanent lines, and to sustain heavy
burdens, turntables with a cast iron box are required, constructed on
the principle of the turntables of ordinary railways. The heaviest
wagons may be placed on these box turntables, without any portion
suffering damage or disturbing the level of the ground. In the case of
coal mines, paper mills, cow houses with permanent lines, etc., fixed
plates are employed. Such plates need only be applied where the line is
always wet, or in workshops where the use of turntables is not of
frequent occurrence. This fixed plate is most useful in farmers'
stables, as it does not present any projection which might hurt the feet
of the cattle, and is easy to clean.
The only accident that can happen to the track is the breaking of a
fish-plate. It happens often that the fish-plates get twisted, owing to
rough handling on the part of the workmen, and break in the act of being
straightened. In order to facilitate as much as possible the repairs in
such cases, the fish-plates are not riveted by machinery, but by hand;
and it is only necessary to cut the rivets with which the fish-plate is
fastened, and remove it if broken: A drill passed through the two holes
of the rail removes all burrs that may be in the way of the new rivet.
No vises are required for this operation; the track to be repaired is
held by two workmen at a height of about 28 in. above the ground, care
being taken to let the end under repair rest on a portable anvil, which
is supplied with the necessary appliances. The two fish-plates are put
in their place at the same time, the second rivet being held in place
with one finger, while the first is being riveted with a hammer; if it
is not kept in its place in this manner it may be impossible to put it
in afterward, as the blows of the hammer often cause the fish-plate to
shift, and the holes in the rail are pierced with great precision to
prevent there being too much clearance. No other accident need be feared
with this line, and the breakage described above can easily be repaired
in a few minutes without requiring any skilled workman.
The narrow-gauge system, which has recently received so great a
development on the Continent, since its usefulness has been
demonstrated, and the facility with which it can be applied to the most
varied purposes, has not yet met in England with the same universal
acceptance; and those members of this Institution who crossed the sea to
go to Belgium were, perhaps, surprised to see so large a number of
portable railways employed for agricultural and building purposes and
for contractors' works. But in the hands of so practical a people it may
be expected that the portable narrow gauge railway will soon be applied
even to a larger number of purposes than is the case elsewhere.
* * * * *
GERARD'S ALTERNATING CURRENT MACHINE.
The machine represented in the annexed engravings consists of a movable
inductor, whose alternate poles pass in front of an armature composed of
a double number of oblong and flat bobbins, that are affixed to a circle
firmly connected with the frame. There is a similar circle on each side
of the inductor. The armature is stationary, and the wires that start
from the bobbins are connected with terminals placed upon a wooden
support that surmounts the machine.
[Illustration: GERARD'S ALTERNATING ELECTRIC MACHINE.]
This arrangement allows of every possible grouping of the currents
according to requirements. Thus, the armature may be divided into two
currents, so as to allow of carbons 30 mm. in diameter being burned, or
else so as to have four, eight, twelve, twenty-four, or even forty-eight
distinct circuits capable of being used altogether or in part.
This machine has been studied with a view of rendering the lamps
independent; and there may be produced with it, for example, a voltaic
arc of an intensity of from 250 to 600 carcels for the lighting of a
courtyard, or it may be used for producing arcs of less intensity for
shops, or for supplying incandescent lamps. As each of the circuits is
independent, it becomes easy to light or extinguish any one of the lamps
at will. Since the conductors are formed of ordinary simple wires, the
cost attending the installation of 12 or 24 lamps amounts to just about
the same as it would in the case of a single cable.
[Illustration: GERARD'S 250 H.P. DIRECT CONNECTION ALTERNATING CURRENT
STEAM DYNAMO-ELECTRIC MACHINE.]
One of the annexed cuts represents a Corliss steam engine connected
directly with an alternating current machine of the system under
consideration. According to the inventor, this machine is capable of
supplying 1,000 lamps of a special kind, called "slide lamps," and a
larger number of incandescent ones.--_Revue Industrielle_.
* * * * *
AUTOMATIC FAST SPEED TELEGRAPHY.
By THEO. F. TAYLOR.
Since 1838 much has been done toward increasing the carrying capacity of
a single wire. In response to your invitation I will relate my
experience upon the Postal's large coppered wire, in an effort to
transmit 800 words per minute over a 1,000 mile circuit, and add my mite
to the vast sum of knowledge already possessed by electricians.
As an introduction, I shall mention a few historical facts, but do not
propose to write in this article even a short account of the different
automatic systems, and I must assume that my readers are familiar with
modern automatic machines and appliances.
In 1870, upon the completion of the Automatic Company's 7 ohm wire
between New York and Washington, it happened that Prof. Moses G. Farmer
was in the Washington office when the first message was about to be
sent, and upon being requested, he turned the "crank" and transmitted
the message to New York, at the rate of 217 words per minute.
Upon his return to New York he co-operated with Mr. Prescott in
experiments on W.U. wires, their object being to determine what could be
done on iron wires with the Bain system. A good No. 8 wire running from
New York to Boston was selected, reinsulated, well trimmed, and put in
first-class electrical condition, previous to the test. The "Little"
chemical paper was used.
The maximum speed attained on this wire was 65 words per minute.
About the same time George H. Grace used an electro magnet on the
automatic line with such good effect that the speed on the New
York-Washington circuit was increased to 450 words per minute.
Then a platina stylus or pen was substituted for the iron pen in
connection with iodide paper, and the speed increased to 900 words per
minute.
In 1880, upon the completion of the Rapid Company's 6 ohm wire, between
New York and Boston, 1,200 words per minute were transmitted between the
cities above named.
In 1882, I was employed by the Postal Telegraph Company to put the Leggo
automatic system into practical shape, and, if possible, transmit 800
words per minute between New York and Chicago.
It was proposed to string a steel-copper wire, the copper on which was
to weigh 500 lb. to the mile.
When complete, the wire was rather larger than No. 3, English gauge, but
varied in diameter, some being as large as No. 1, and it averaged 525
lb. of copper per mile and = 1.5 ohms. The surface of this wire was,
however, large.
Dr. Muirhead estimated its static capacity at about 10 M.F., which
subsequent tests proved to be nearly correct.
It will be understood that this static capacity stood in the way of fast
transmission.
Resistance and static capacity are the two factors that determine speed
of signaling.
The duration of the variable state is in proportion to the square of the
length of the conductor, so that the difficulties increase very greatly
as the wire is extended beyond ordinary limits. According to Prescott,
"The duration of the variable condition in a wire of 500 miles is
250,000 times as long as in a wire of 1 mile."
In other words, a long line _retains a charge_, and time must be allowed
for at least a falling off of the charge to a point indicated by the
receiving instrument as zero.
In the construction of the line care was taken to insure the _lowest
possible resistance_ through the circuit, even to the furnishing of the
river cables with conductors weighing 500 lb. per mile.
Ground wires were placed on every tenth pole.
When the first 100 miles of wire had been strung, I was much encouraged
to find that we could telegraph without any difficulty past the average
provincial "ground," provided the terminal grounds were good.
When the western end of this remarkable wire reached Olean, N.Y., 400
miles from New York, my assistant, Mr. S.K. Dingle, proceeded to that
town with a receiving instrument, and we made the first test.
I found that 800 words, or 20,000 impulses, per minute, could be
transmitted in Morse characters over that circuit _without compensation_
for static.
In other words, the old Bain method was competent to telegraph 800 words
per minute on the 400 miles of 1.5 ohm wire.
The trouble began, however, when the wire reached Cleveland, O., about
700 miles from New York.
Upon making a test at Cleveland, I found the signals made a continuous
black line upon the chemical paper. I then placed both ends of the wire
to earth through 3,000 ohms resistance, and introduced a small auxiliary
battery between the chemical paper and earth.
The auxiliary or opposing battery was placed in the same circuit with
the transmitting battery, and the currents which were transmitted from
the latter through the receiving instrument reached the earth by passing
directly through the opposing battery.
The circuit of the opposing battery was permanently completed,
independently of the transmitting apparatus, through both branch
conductors and artificial resistances.
The auxiliary battery at the receiving station normally maintained upon
the main line a continuous electric current of a negative polarity,
which did not produce a mark upon the chemical paper.
When the transmitting battery was applied thereto, the excessive
electro-motive force of the latter overpowered the current from the
auxiliary battery and exerted, by means of a positive current, an
electro-chemical action upon the chemical receiving paper, producing a
mark.
Immediately upon the interruption of the circuit of the transmitting
battery, the unopposed current from the auxiliary battery at the
receiving station flowed back through the paper and into the main line,
thereby both neutralizing the residual or inductive current, which
tended to flow through the receiving instrument, and serving to clear
the main line from electro-static charge.
The following diagram illustrates my method:
Referring to this diagram, A and B respectively represent a transmitting
and a receiving station of an automatic telegraph. These stations are
united in the usual manner by a main line, L. At the transmitting
station, A, is placed a transmitting battery, E, having its positive
pole connected by a conductor, 2, with the metallic transmitting drum,
T. The negative pole of the battery, E, is connected with the earth at G
by a conductor, 1. A metallic transmitting stylus, t, rests upon the
surface of the drum, T, and any well known or suitable mechanism may be
employed for causing an automatic transmitting pattern slip, P, to pass
between the stylus and the drum. The transmitting or pattern slip, P, is
perforated with groups of apertures of varying lengths and intervals as
required to represent the dispatch which it is desired to transmit, by
an arbitrary system of signs, such, for example, as the Morse
telegraphic code.
At the receiving station, B, is placed a recording apparatus, M, of any
suitable or well known construction. A strip of chemically prepared
paper, N, is caused to pass rapidly and uniformly between the drum, M',
and the stylus, m, of this instrument in a well known manner. The drum,
M', is connected with the earth by conductors, 4 and 3, between which is
placed the auxiliary battery, E, the positive or marking pole of this
battery being connected with the drum and the negative pole with the
earth. The electro-motive force of the battery, E', is preferably made
about one-third as great as that of the battery, E.
[Illustration]
Extending from a point, o, in the main line, near the transmitting
station, to the earth at G, is a branch conductor, l, containing an
adjustable artificial resistance, R. A similar conductor, ll, extends
from a point, o', near the receiving terminal of the line, L, to the
conductor, 3, in which an artificial resistance, R', is also included,
this resistance being preferably approximately equal to the resistance,
R. The proportions of the resistance of the main line and the artificial
resistances which I prefer to employ may be approximately indicated as
follows: Assuming the resistance of the main line to be 900 ohms, the
resistance, R, and R', should be each about 3,000 ohms. The main
battery, E, should then comprise about 90 cells, and the auxiliary
battery, E', 30 cells.
The operation of my improved system is as follows: While the apparatus
is at rest a constant current from the battery, E', traverses the line,
L, and the branch conductors, l, and ll, dividing itself between them,
in inverse proportion to their respective resistances, in accordance
with the well-known law of Ohm. When the transmitting pattern strip, P,
is caused to pass between the roller, T, and the stylus, t, electric
impulses will be transmitted upon the line, L, from the positive pole of
the battery, E, which will traverse the main line, L, the two branch
lines, l, and ll, and their included resistances, and also the receiving
instrument, M. The greater portion of this current will, however, on
account of the less resistance offered, traverse the receiving
instrument, M, and the auxilary battery, E'. The current from the
last-named battery will thus be neutralized and overpowered, and the
excess of current from the main battery, E, will act upon the chemically
prepared paper and record in the form of dots and dashes or like
arbitrary characters the impulses which are transmitted.
Immediately on the cessation of each impulse, the auxiliary battery, E',
again acts to send an impulse of positive polarity through the receiving
paper and stylus in the reverse direction and through the line, L, which
returns to the negative pole of the battery by way of the artificial
resistances, R and R'. Such an impulse, following immediately upon the
interruption of the circuit of the transmitting battery, acts to destroy
the effect of the "tailing" or static discharge of the line, L, upon the
receiving instrument, and also to neutralize the same throughout the
line. By thus opposing the discharge of the line by a reverse current
transmitted directly through the chemical paper, a sharply defined
record will in all cases be obtained; and by transmitting the opposing
impulse through the line, the latter will be placed in a condition to
receive the next succeeding impulse and to record the same as a sharply
defined character.
This arrangement was made on the New York-Cleveland circuit, and the
characters were then clearly defined and of uniform distinctness. The
speed of transmission on this circuit was from 1,000 to 2,000 words per
minute.
Upon the completion of the wire to Chicago, total distance 1,050 miles,
including six miles of No. 8 iron wire through the city, the maximum
speed was found to be 1,200 words per minute, and to my surprise the
speed was not affected by the substitution of an underground conductor
for the overhead wire.
The underground conductor was a No. 16 copper wire weighing 67 pounds
per mile, in a Patterson cable laid through an iron pipe.
I used 150 cells of large Fuller battery on the New York-Chicago
circuit, and afterward with 200 cells in first class condition,
transmitted 1,500 words, or 37,000 impulses, per minute from 49
Broadway, New York, to our test office at Thirty-ninth Street, Chicago.
The matter was always carefully counted, and the utmost care taken to
obtain correct figures.
It may be mentioned as a curious fact that we not only send 1,200 words
per minute through 1,050 miles of overhead wire and five miles of
underground cable, but also through a second conductor in No. 2 cable
back to Thirty-ninth Street, and then connected to a third underground
conductor in No. 1 cable back to Chicago main office, in all about
fifteen miles of underground, through which we sent 1,200 words per
minute and had a splendid margin.--_Electrical World_.
* * * * *
[ELECTRICAL REVIEW].
THEORY OF THE ACTION OF THE CARBON MICROPHONE--WHAT IS IT?
A careful examination of the opinions of scientific men given in the
telephone cases--before Lord McLaren in Edinburgh and before Mr. Justice
Fry in London--leads me to the conclusion that scientific men, at least
those whose opinions I shall quote, are not agreed as to what is the
action of the carbon microphone.
In the Edinburgh case, Sir Frederick Bramwell said: "The variations of
the currents are effected so as to produce with remarkable fidelity the
varied changes which occur, according as the carbon is compressed or
relieved from compression by the gentle impacts of the air set in motion
by the voice."
"The most prominent quality of carbon is its capability, under the most
minute differences of pressure, to enormously increase or decrease the
resistances of the circuit." "That the varying pressure of the black
tension-regulator (Edison's) is sufficient to cause a change in the
conducting power." Sir Frederick also said "he could not believe that
the resistance was varied by a jolting motion; could not conceive a
jolting motion producing variation and difference of pressure, and such
an instrument could not be relied on, and therefore would be practically
useless."
Sir William Thomson, in the same case, said: "The function of the carbon
is to give rise to diminished resistance by pressure; it possesses the
quality of, under slight degrees of pressure, decreasing the resistance
to the passage of the electric current;" and, also, "the jolting motion
would be a make-and-break, and the articulate sounds would be impaired.
There can be no virtue in a speaking telephone having a jolting motion."
"Delicacy of contact is a virtue; looseness of contact is a vice."
"Looseness of contact is a great virtue in Hughes' microphone;" and "the
elements which work advantages in Hughes' are detrimental to the good
working of the articulating instrument."
[Illustration: Fig. 1.]
Mr. Falconer King said: "There would be no advantage in having a jolting
motion; the jolting motion would break the circuit and be a defect in
the speaking telephone," and "you must have pressure and partially
conducting substances."
Professor Fleeming Jenkin said, "The pressure of the carbons is what
favors the transmission of sound."
All the above named scientific men agree that variations of a current
passing through a carbon microphone are produced by _pressure_ of the
carbons against one another, and they also agree that a jolting motion
could not be relied upon to reproduce articulate speech.
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