PEUA TIC  SCH
PNEUM1VAT1C DISPATCH,
WITH ILLUSTRATIONS:
A Compilation of Jrotices and Infbrmation. concerning the iP nezfmatic
Systenz of Trcnsportation as now BciZldingq and Opecrating z'
England; together withz ccounts of' its irst'rial in
the u7nited States, and of' froposed ALpplications
oj the System to cPassenger and ~Postal
Service:
INCLUDING
rseripttians of ib-u qutuou$ anb otlcr  unneIs
)3Y    LFR ED. BEACH.
THE AMERICAN NEWS COMPANY, NASSAU STREET.
1868.




ENTERED, according to Act of Congress, in the year 1868, by
ALFRED E. BEACH,!n thie (Clerk's Office of the District Court of the United States for tie Southern District
of New-York.




INTRODUCTION.
THE information here presented consists mostly of compilations from
reliable sources, which will, it is believed, be of interest to those who
are desirous of forming a just estimate of the value of the Pneumatic
system as a commercial enterprise.
The accounts given exhibit the practical progress of the system
from the first public experiment at Battersea Fields, in 1861, down to
January, 1868. During this period of seven years the Pneumatic system
has been introduced in London with entire success, where it is now in
regular operation in connection with the postal service.
Thorough practical trials with reference to passenger transportation
have also been had in London, which have so completely demonstrated
the success and importance of the system as to warrant the construction
of a Pneumatic Passenger Railway from Charing Cross, under the
Thames River, to the Waterloo station of the Southwestern Railway.
This road is not yet wholly completed.
In this country the first public trial of the Pneumatic Railway took
place at the American Institute in the fall of 1867, when many thousands of passengers enjoyed the atmospheric ride. Charters for Pneumatic Railways have been granted in the States of Pennsylvania, NewJersey, Connecticut, and Massachusetts. Applications for charters are
pending before the Legislatures of New-York and other States.
The engravings of the London Pneumatic Railways are from drawings taken from the works.
ALFRED E. BEACH.
NEW-YORK, January, 1868.








THE PNEUMATIC DISPATCH.
BY ALFRED E. BEACH.
CHAPTER I.
THE PNEUMATIC DISPATCH - ITS GENERAL PRINCIPLES, CHARACTERISTICS,
C!.APABILITIES, AND ADVANTAGES —FIRST PUBLIC TRIAL AT BATTERSEA
FIELDS, NEAR LONDON, IN 1861 -PARTICULARS CONCERNING ITS CONSTRUCTION AND MODE OF OPERATION —ENTIRE SUCCESS OF THE EXPERIMIENT.
THE method of communication known as the Pneumatic Dispatch consists of a railroad track inclosed in a tube, the cars being driven by
atmospheric pressure. The car, in effect, is a piston, moving within the
tube.
The velocity of the car is in proportion to the degree of atmospheric
pressure, which is produced by means of a fan or blower, operated by a
stationary steam-engine.
The mechanism for operating the Pneumatic Dispatch is of the simplest
description. A tube, a car, a revolving fan! Little more is required. The
ponderous locomotive, with its various appurtenances, is dispensed with,
and the light aerial fluid that we breathe is the substituted motor.
The Pneumatic Dispatch is not a chimebra, nc' merely an untried, undeveloped novelty. It has been in practical operation in London for the
last seven years, where its capabilities for useful service have been tested
in the most careful and thorough manner. The results of these years of
actual employment conclusively show that it has economical advantages
over the present railway system, and there seems little reason to doubt
that its introduction will become extensive.
The Pneumatic Dispatch presents theoretical facilities for obtaining
high velocities. Air rushes into a vacuum at the rate of 700 miles an
hour. If the proper mountings for a light piston and finish for the tube
could be realized, it is supposed that a velocity of piston approaching this
might be obtained. The experimental pneumatic passenger cars at Sydenham ran through the tube at the rate of twenty miles an hour, with an
atmospheric pressure of only two and a half ounces to the square inch.
On the old Croydon Atmospheric Railroad, where the small slotted airtube was used and the leakage was very great, the cars could be driven at
a velocity of a mile a minute, or sixty miles an hour.
IL is believed that, under the improved system of sending the car
through the tube, a speed of 100 miles an hour may be safely realized, or
four times the average speed of many of our best railroads.
The great destroying agent upon all roads is the locomotive, which,
with its tender, often weighs thirty tons. To support this immense mov



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THE PNEUMATIC DISPATCH.                       7
ing burden, the bridges, rails, and superstructure must have corresponding
strength, and even then they are rapidly battered to pieces and rendered
unsafe.
To resist the wrenchings of the locomotive and the rough usages c f the
track, the cars must be much more heavily timbered and framed than i,
needful to support the loads they carry.
In the pneumatic system no locomotives are employed. Hence, the
roadway and cars may be very light. The whole pneumatic way being
under cover, the road-bed is preserved from damage by the elements, and
the transit of the cars is not impeded by snow, ice, floods, or falling rocks.
For freight purposes, simple platform trucks, strong enough to support the
load, are sufficient. Thus the enormous dead weight of the sides, frames,
ends, and roofs of the ordinary box cars is avoided.
Laid through the country, the tube will be wholly or partly buried in
the earth, its whole business being performed with the celerity of JEolus,
with the silence of Somnus.
The expensive bridges, culverts, trestle-works, cuts, and embankments,
required upon common railroads, are not wanted in the pneumatic system.
The tube forms the bridge over small streams, dives under broad waters,
and rests securely upon marshes. No screeching whistles or jangling bells
disturb the community, no turnpikes require to be guarded; there is no
running down of the helpless, no mangling of passengers, no burnings
from sparks; no fearful dangers of any kind attend the use of the Pneumatic Dispatch.
It is impossible to say what casualties are likely to attend its working;
but, from the elastic nature of the motor, we conclude that they will be
rare in number, and less violent in their nature than those that are experienced upon common railroads. During the whole seven years' use of the
pneumatic system in London, we believe that not a single accident to person has ever been recorded; nor do we know that there has even been so
much as a break-down of any pneumatic car.
First Public Trial of the Pneumatic Dispatch at Battersea Fields,
near London, in 1861.
[From the London Mechanics' Magazine, July 19,1861.]
THE PNEUMATIC DISPATCH COMPANY.
ON Wednesday last some experiments, on a rather large scale, were
made on the right bank of the river, and immediately below the railway
bridge, Battersea, with a view to testing the efficiency of the novel mode
of transmitting goods and parcels proposed by the above-named company,
The mechanical arrangements in connection with the experimental line of
cast iron tubing-which, like a huge black snake, stretches for more than a
quarter of a mile along the river side-are few and simple.
Under a temporary shed a high-pressure steam-engine, of thirty horsepower, made by Watt & Co., and having its cylinder placed at an angle
of forty-five degrees, is erected, and it gives direct motion, through the
medium of a crank, to a large disk of sheet-iron. The disk runs on tubular
bearings, and narrows from about two feet six inches in breadth at its centre
to three inches at its circumference, its diameter being eighteen feet. Itsinterior contains simply four arms to which the sheets of iron are fastened,
and which serve as fans or exhausters. Through the hollow bearings, upon
which the disk is made to rotate at a speed of from one hundred and fifty




8                    THE PNEUMATIC DISPATCH.
to two hundred revolutions per minute, a communication exists with a
vacuum-chamber below, and, by the laws of centrifugal action, the latter is
speedily exhausted, to a certain extent, of air. The speed of the disk, in fact,
determines that extent, and a water-barometer registers it. The air rushes
out with considerable force from the periphery of the disk.
Between the vacuum-chamber and the pneumatic tube, which is two feet
nine inches high by two feet six inches in breadth, and a transverse section
of which resembles that of the Thames tunnel, there are fitted valves with
hand-levers for opening and shutting them.  These may be said to comprise the whole of the motive and propelling agencies of the pneumatic systern; and it must be allowed that they are not complicated, or likely to get
out of order.
The tube has been laid down in Battersea Fields in such a manner as to
test severely the practicability of the scheme. It has several very sharp
curves and steep gradients throughout its length, and is socket-jointed, so
as to leave its interior, which is just as it came from the sand, free from
obstruction. The carriages are five feet in length, of sheet-iron, and each
runs upon four cast iron wheels of eighteen inches in diameter. The rails, so
to speak, are cast in the bottoms of the tubes, and require, therefore, no " laying " but that which the setting of the tubes themselves gives them. A few
strips of vulcanized india-rubber screwed round the circumference of the
fore end of the carriage constitute the piston. This, however, by no means
closely fills the tube. In fact, there is fully three eighths of an inch clear
between the exterior of the piston and the interior of the tube. There is no
friction, therefore, and, singular to say, the leakage of air does not interfere with the speed of transit. This can only be accounted for by the large
end area which the carriages have, in comparison with the small area of
leakage space, and the comparatively low vacuum required.
On Wednesday last the first experiment made was by loading a carriage
with one ton of cement, in bags, and entering it into the open end of the
tube. Upon a given signal Mr. Rammel, the engineer to the company,
caused the starting-valve to be opened, the water-barometer showing a
column seven inches in height, and the disk running at a rate of one hundred and fifty revolutions per minute. In fifty seconds after, the carriage,
with its contents, found its way into the engine-house, through a door at
the end of the tube, which it forced open, and then ran forward on rails to
a butt placed to stop its progress. Next, two tons weight were placed in
one of the carriages, and its transit occupied eighty seconds, under similar
circumstances. The vacuum was now lowered until the barometer-gauge
showed two inches of water only, and a living passenger, in the shape of a
not very handsome dog, was placed, with one ton weight of dead stock, in
a carriage. The signal was made by the workmen at the open end of the
tube, the communicating valve was opened, and in one minute and a half
the carriage and its four-legged guard were in the engine-house, the latter
apparently not at all the worse for the exhausting process to which he had
been subjected. Other experiments of an equally satisfactory nature followed, and, on the whole, we augur well of the entire scheme. Sir Joseph
Paxton, H. W. Blake, Esq., and other gentlemen of scientific eminence
were present on the occasion, and expressed their pleasure in witnessing
the experiments.




THE PNEUMATIC DISPATCH.                      9
[From the London Engineer, July 26, 1861.]
PNEUMATIC DISPATCH.
THE atmospheric post has been at work for a few days, and experimentally, in Battersea Fields. An iron tube, upward of a quarter of a mile
long, has been laid along the river's bank, and mail-bags, parcels, and even
adventurous navvies have been whisked through at the rate of twenty-five
miles an hour. Those who, some twenty years ago, witnessed the working
of the atmospheric railway, may discover nothing new in the principle.
But the application is altogether different. There is still the tube and the
exhausting apparatus, but the load, instead of being drawn over rails laid
alongside of the tube, goes through it. No self-sealing valves, therefore,
are necessary. As, also, the load is comparatively light, a very low degree
of exhaustion suffices for every purpose of propulsion. Air flows into a
vacuum with a velocity of about one thousand feet per second, or nearly
seven hundred miles an hour, and it would be possible to send a light object
at something approaching this rate through a smooth tube, from which all
the air had been first exhausted. Even with such a vacuum as could be
maintained in the Croydon Railway tubes, and with all the load attached,
the trains sometimes attained a speed of nearly a mile a minute.
The tube, in its course, is sharply curved, and presents also steep gradients, in one case a slope of one in twenty, equal to the average rise of Holborn Hill. The minimum curve is of forty feet radius. The air is exhausted,
from near one end of the tube, by means of an exhausting apparatus, from
which the air is discharged by centrifugal force.
The invention of the arrangements above described is due to T. W.
Rammell, Esq., C. E., the Secretary of the Pneumatic Dispatch Company.
This company has been organized under the chairmanship of the Marquis
of Chandos, the vice-chairman being Captain Huish. It is the intention of
the company, now that they have obtained parliamentary powers for opening the streets to lay down their tubes, to establish a line between St.
Martin's-le-Grand and one of the district post-offices, and ultimately to
extend their system throughout the metropolis, so as to connect the railway
stations, public offices, etc. Both these services could be profitably performed, it is urged, by the Pneumatic Dispatch, at a speed of thirty miles
an hour, without obstructing the thoroughfares, and with other advantages
which sufficiently suggest themselves upon reflection.
[From the Scientific American of October 5, 1861.]
PNEUMATIC DISPATCH.
A COMPANY has been formed in London, under the title of the Pneumatic
Dispatch Company, for establishing lines of pneumatic tube for the speedy
conveyance of letters and parcels. The chief feature of the invention consists in propelling a train of carriages through a tube by the creation of a
vacuum before them; the tube being, in fact, the cylinder, and the carriages the piston. A piece of ground adjoining the Victorian Railway
bridge at Battersea, and belonging to the Vauxhall Water-works Company,
and London and Brighton Company, has been selected for testing the project. Here upward of a quarter of a mile of the tubing has been laid down,
various irregular curves and gradients being introduced to show that hills
and valleys would not prevent the effective working of the system. The
apparatus certainly works well.
Some successful experiments were lately made. One trip was made in




10                   THE PNEUMATIC DISPATCH.
sixty seconds, and a second in fifty-five seconds, the distance being a quarter
of a mile. Two gentlemen occupied the carriages during the first trip.
They lay on their backs on mattresses, with horse-cloths for coverings, and
appeared to be perfectly satisfied with their journey. It is calculated that
the carriages will eventually move through the tubes at the rate of from
thirty to forty miles an hour.
CHAPTER II.
LAYING DOWN OF TIlE FIRST PNEUMATIC TUBES UNDER THE STREETS OF LONDON-SUCCESSFUL INAUGURATION OF THE ENTERPRISE-CONNECTION
OF RAILWAY STATIONS AND THE GENERAL POST-OFFICE BY MEANS OF
THE PNEUMATIC TUBES -DESCRIPTION OF THE MANNER OF SENDING
THE MAILS THROUGH THE TUBES-REPORT OF THE DIRECTORS-INSPECTION BY TIHE POSTMASTER-GENERAL - EXPENSES OF WORKING - DESCRIPTION OF TIlE MACHINERY-EXTENSION OF TIHE WORKS-INAUGURATION OF THE HOLBORN STREET STATION.
[From the London Mechanics' Magazine, February, 1863.]
INSPECTION OF THE PNEUMATIC DISPATCH BY THE POSTAIASTER-GENERAL
AND SIR ROWLAND HILL.
ON Monday last, Lord Stanley, of Alderley, the Postmaster-General,
and Sir Rowland Hill, the Secretary of the Post-Office, officially inspected
the working arrangements of the branch tube of the Pneumatic Dispatch,
(which has been laid from the Euston station to the north-western PostOffice, in Eversholt street,) previous to the transmission of the mails between
the two places above-mentioned; the Post-Office authorities having conceded this privilege to the Pneumatic Dispatch Company. The time appointed for the inspection was half past twelve P.r., and on the arrival of
the Postmaster-General and Sir Rowland Hill at the station, within the
boundary of the Euston terminus, they were received by Sir Charles Rich, one
of the directors, Mr. Margery, and Rammell, the secretary and engineer of
the Pneumatic Dispatch; Messrs. Blake and Stewart, of the London and
North-Western Railway, being among those present. The working arrangements were thoroughly explained by Mr. Rammell, the engineer, and trains
of cars were rapidly propelled backward and forward through the tubes.
The cars contained heavy weights, being principally loaded with stout
planks, and, on the signal being given by Wheatstone's admirable telegraph,
they were dispatched to the other end of the tube, with a pressure of about
four ounces, in a few seconds over a minute, the average up the incline
being about one minute twelve seconds, returning by vacuum in one minute
five seconds. The mail-bags, upward of 120 per day, will be blown through
the tube in fifty-five seconds to the Post-Office, Eversholt street, the usual
time occupied by the mail-carts being at present about ten minutes. Two
persons were conveyed, in the presence of the Post-Office authorities,
through the tube, and returned by vacuum without having experienced the
slightest discomfort. Having fully examined the operation of blowing the
cars from Euston, the visitors proceeded to the station at the other end of
the tube. This is situated underground, beneath the roadway of a small
turning leading from Eversholt street, and is close by the side of the Northwestern District Post-Office. Here the very interesting operation of send



THE PNEUMATIC DISPATCH.                     11
ing the cars back to Euston was explained by Mr. Rammell; and two cars
having been placed within about a foot of the open tube, a vacuum was
created, and they were drawn with a rush into the tube, the small station
reverberating with the sound of the receding train. This concluded the experiments of the day, and, on leaving, both Lord Stanley and Sir Rowland
Hill appeared favorably impressed with the entire working of the system,
the Postmaster-General observing that it appeared, from the experiments,
to be very satisfactory and very efficient.  Previous to leaving the station
at Euston, Lord Stanley descended with Mr. Rammell into the air-chamber
of the revolving disk, the motive-power of which consists of a fifteen horsepower engine.  The next step of the company will be to lay tubes connecting the markets of London with Camden goods-station, with a tube to
the General Post-Office, and Pickford's depot, in Gresham street, and these
operations will eventually tend to revolutionize the carrying system of
the metropolis, and relieve the crowded state of our principal thoroughfares.
[From the London Mechanics' Magazine, July 31,1863.]
REPORT OF THE DIRECTORS OF THE PNEUMATIC DISPATCH COMPANY.
THE Directors of the Pneumatic Dispatch Company state in their report
that the experimental tube and machinery have been removed from Battersea, and laid underground from the Euston Station of the London and NorthWestern Company, to the District Post-Office, in Eversholt street. The
length of the tube is 600 yards. On the 20th of February last, the PostOffice authorities intrusted the company with the transmission of the mails.
From that date the service of the district has been entirely performed by
the company.  Thirty trains per diem (Sundays excepted) have been dispatched with perfect regularity, and upward of 4000 trains have run without
impediment or delay. The time occupied in the transmission has not exceeded
seventy seconds. The daily cost of working has averaged ~1 4s. 5d., and five
times the number of trains could have been conveyed without any appreciable
increase of expense. Confirmed in their views by this result, the directors
proceeded to carry out the decision of the last general meeting, by the
issue of a capital sufficient to enable the company to lay a main line of tube
fifty-four inches in diameter, with the necessary stations, appliances, and
machinery, from the Euston station to the General Post-Office, in St.
Martin's-le-Grand, and forward to Gresham street. This capital having
been subscribed, the directors entered into contracts with Mr. Barrow, of
Stavely, Messrs. James Watt & Co., and Messrs John Airel & Son, for its
completion. The length of this tube will be nearly two and one half miles,
and the entire cost, so far as can be foreseen, including the laying, stationaccommodation, and the necessary apparatus and pumping engines, will be
about ~65,000.  The whole route has been carefully examined and definitely determined. From the active measures taken by the contractors in
the preparation of the tube and engines, the directors hope to commence
laying the line at an early date, and will press forward its completion with
all practicable expedition. A considerable portion of the further issue of
shares has been taken up by the original proprietors and the contractors,
and the remainder has been allotted among seventy-six new shareholders.




12                   THE PNEUMATIC DISPATCH.
[From the London Practical Mechanics' Journal, June 1, 1863.]
THE PNEUMATIC DISPATCH.
THE Pneumatic Dispatch, as its name imports, was originally conceived
as a method of carrying letters or dispatches only, and proposed its arrangements to be on a very small scale. Though bearing the same name,
it has become, in the hands of Mr. Rammell, C. E., who may be viewed as
the creator of the pneumatic arrangements now in use at the Euston terminus of the London and North-Western Railway, a method of transport
applicable upon almost any scale, and to materials of whatever sort, or even
to passengers. The apparatus actually in use is applied to the transport
of the mail-bags, as they arrive by the line of railway, from the terminus
to the District Post-Office in Eversholt street-distant about 1800 feet.
Almost close to the arrival platform at the Euston terminus is seen a
small, newly finished, one-story building with a slender chimney-stalk at
one side. This is, as the board above the doorway tells, the present terminus here of the Pneumatic Dispatch. Descending two or three steps,
we are in the interior, and find a small cast iron tunnel, with arched top
and nearly flat bottom, carrying a pair of rails, one at either lower angle,
and about two feet nine inches high, by nearly the same greatest width,
passing out through the wall at one side. The rails, which are on the floor
level, cross it, and at the opposite wall appear to run into a corresponding
tunnel; this is, however, only a cul de sac of a few feet in length, and its
use is merely to afford an air buffer to the mail-bag carriages when arriving back here from Eversholt street office, should their velocity be such
as to require it, which is seldom the case.
In the middle of the floor, upon the rails between these two tunnelmouths, we observe two or three iron four-wheeled wagons, formed in the
shape of hollow, cradle-like boxes of considerable capacity, which conform
externally to the general form of the tunnel-tubes they are to pass through,
but have an absolute clearance all round, of more than an inch between
their sides and those of the tubes.  The tunnel-tubes are of cast iron
in ordinary lengths, put together with leaded spigot and faucet joints,
like common street mains. They pass beneath the yards of the station,
and the streets, etc., having gradients nowhere quite level, and varying
from one in one hundred to as much as one in eighty. These comprehend three important curves, two reverse to each other at Euston station,
of 1,10 feet radius each, and one at the Post-Office at the remote end, of
only forty feet radius. This was a local necessity, but has given an occasion of proving the flexibility with which these arrangements can adapt
themselves to the sharp turns that must be encountered by any subways
that conform to the streets of cities, and especially of old ones.
At Eversholt street terminal there is no apparatus of any sort, except
that in a small building, obliged by local circumstances to be underground,
there is found the open end of the tunnel tube, a pair of rails coming out
of it across a small floor, and a buffer tube opposite, as already described.
The whole of the apparatus by which these carriages that are standing
in the middle before us are transmitted hence to the Post-Office, and brought
back thence again to where they stand, whether full or empty, is here in the
building at Euston in which we stand. Of what does it consist? Turning
our backs to the carriages we see a large, flat, round-topped casing, made
of boiler plate, about twenty-two and one half feet wide by about four feet
thick, at about four feet above the ground level. We observe that both
sides of the casing are traversed by a strong wrought iron shaft, resting on




THE PNEUMATIC DISPATCH.                     18
plummer-blocks and cast iron framing, upon the front of which we recognize the stirring name of the makers, James Watt & Co., Soho.
This casing is that of the Pneumatic Ejector.  This is the instrument
by which air is put in motion either to propel the carriages forward from
Euston, by blowing wind into the tunnel behind them, or e converse, by
which they are drawn back from Eversholt street terminal, by producing
a partial vacuum in the tunnel, into which the atmosphere at the remote
end entering, drives the carriages on before it. The Pneumatic Ejector is
a very peculiar form of centrifugal machine, the invention of Mr. Rammell,
capable of performing all the functions, in the expulsion or exhaustion of
air, to which the ordinary and well-known forms of revolving fan for producing blast are applicable, but with immense advantages in principle over
those clumsy and noisy instruments, the reality and economy of which have
been now practically demonstrated. We shall return to it presently. Passing
behind the large bulk of this casing with its air-wheel of twenty-one feet
diameter inside, we find a small high-pressure steam-engine, a single cylinder of fifteen inches diameter and sixteen inches length of stroke, upon inclined framing, and with its connecting-rod taking on to a crank-pin and
crank, keyed directly on upon the end of the central shaft of the Pneunmatic Ejector.
Alongside the engine is the boiler, an ordinary cylindrical one, with
internal fire, and giving steam at forty pounds pressure to the engine.
This, with the arrangements for closing and opening the end of the tun.
nel here, after the dispatch, or on the arrival of the train of carriages, and
those for enabling the ejector either to blow into, or draw out of, this end
of the tunnel, constitute literally the whole apparatus-if we except the
electric telegraph, by which communication between the terminals is kept
up; and nothing gives to the mind of the practical engineer a more certain
assurance of the future achievements that await this mode of transport and
locomotion than the absolute simplicity of its parts, the paucity of detail,
and the silence with which it works when in action.
A train of mail-bags is about to be sent down to the Post-Office, and the
train directly returned, and for our especial information it is delayed a few
moments, while, under the escort and with the running commentary of the
inventor, we enter the casing of the pneumatic ejector by a door at one
side, and make ourselves acquainted with its construction.
Within the casing, and well balanced upon its central shaft, which
passes horizontally across from side to side, is a hollow circular disk of
plate iron. The opposite sides of this disk are surfaces of revolution generated by curves, which are nearly hyperbolas, having a common asymptote at the axis, and terminating at the periphery almost in tangents parallel
to the plane of revolution. At either side of the casing, at its central part,
there rises up a cast iron air-trunk, having a united transverse area more
than equal that of the tunnel, and whose outer extremities when united can,
by means of throttle-valves and branch pipes, be placed either in communication with the open air, or with the interior of the tunnel (at this
end) only. These air-trunks terminate at either side of the revolving disk
in circular mouths of about three feet in diameter, to which corresponding
mouths at the centre of the disk are adapted, and while the latter is free to
revolve, are made air-tight at the circles of contact by means of an ordinary
cup leather. The central shaft is fixed in the disk by radial rib feathers,
and the curved sides of the disk are stiffened and connected by radial ribs.
The width of the space at the periphery, between the sides or cheeks, is
only about two inches. The property of the curve which determines the
form is such that a circumferential section of the space between the cheeks
is every distance from the centre the same, and equal to the area of the




14                   THE PNEUMATIC DISPATCH.
central indraft apertures just described. When rotation is given to the
disk the whole plate of air within it is caused to revolve with it; and as in
other centrifugal machines, the air is thrown off or out, all around the periphery, with a velocity proportionate to the deviating force, and its place
supplied by other air drawn in at the central apertures round the shaft.
The air delivered from the periphery is discharged into the casing, and
from this, by arrangements of pipes and valves, it can be either blown into
the tunnel-along the lateral branch extending some distance from the
ejector-when the object is to propel the train before the wind, or the air
beilg, in common language, sucked out of the tunnel, through the branch
pipe, when the object is to draw the train back; the wind thus extracted
is blown off into the open air by a passage provided beneath the floor, and
on a level with the bottom of the ejector casing.
At the Euston entrance of the tunnel, after the train has been pushed
into the interior, the end is closed by a light flap-door of plate iron.
This door is balanced and provided with detents, so arranged that it is
opened automatically by the returning train about to debouch from the
tunnel. The wheels in advance of the first carrige run over a pair of rollers, slightly projecting above the level of the rails, and mounted on the
ends of two long levers. The roller-ends of these levers are depressed by
the weight of the carriage, and these act on the detents and release the
balance weights, which descend a few inches, and the door flies up and
open an instant or two before the train makes its exit. A large adjustable
valve, placed on top of the tunnel, gives the means, with perfect ease and
certainty, of checking the incoming velocity of the train, so that in almost
every instance the carriages come to rest within four or five yards of the
same spot, and of the mouth of the tunnel.
Upon the occasion of our visit we saw a train run off to Eversholt street
and return back in an interval of time that seemed incredibly short. The
curve of forty feet radius obliges the reduction of speed a little at that point.
Taking this into account, the actual working speed, through this bended
and not favorably graded tube, is that of 520 yards in sixty-five seconds, or
nearly sixteen and a half miles per hour. This is effected by a velocity of
revolution of the ejector of about 100 to 110 per minute, which produces
an atmospheric pressure of from three to four inches of water by the gauge,
whether the air be moved in the one direction or the other, which is equivalent to about "a five-ounce gale," as the motive pressure is technically
called by those in charge of the apparatus.
At the present time, about fifteen mails per day are transmitted forward
and backward over the whole distance-beinf the whole traffic that the
London and Northwestern Railway can supply to the District Post-office
at Eversholt street.
From what has been stated as to the short time occupied in passing a
train, it will be seen that the instrument is greatly more powerful than the
demand here upon it, and that for a very large proportion of the whole
time that steam has to be kept up during the day, the apparatus is actually
idle, waiting for work; but even under this disadvantage, the consumption
of fuel (coke, and a little coal) per day of ten hours, including getting up
steam, amounts to but twenty-one bushels, and costs about six shillings, so
that the charge for fuel is even now only about five-pence per double
journey.
Arrangements are now in progress, we are informed, for extending the
communication from Euston to the General Post-Office, and to several other
district stations, when it is expected that the apparatus will be constantly,
or nearly so, at work, and thus the cost of the aerial haulage reduced to a
minimum, which will then obviously be a very small one.




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16                  THE PNEUMATIC DISPATCH.
OPENING OF THE HOLBORN EXTENSION OF THE PNEUMATIC DISPATCH, IN
LONDON.
[From the London " Mechanics' Magazine," Oct. 13, 1865.]
PNEUMATIC DISPATCH RAILWAY.
THE works of the above line between iHolborn and Euston Station are
now completed, and the line ready for opening. To test the working of
the company's tube, on Tuesday last, a small goods-train was driven
through from the Central Station in Holborn, passing beneath Holborn,
New Oxforn street, Tottenham Court road, Hampstead road, and Drummond street, on to the Euston Station, a distance of about two miles,
having some sharp curves on approaching the North-Western Station.
The tube is four feet six inches high, and about the same width, the rails
being fixed in it for the carriage-wheels to run upon. At the Central Station, in Holborn, two tubes are carried beneath the footway and groundfloor of the building; one connecting Euston Station with the Central
Station, and the other being intended to connect the latter with the Postoffice in St. Martin's-le-Grand. This tube has only been carried to Holborn
Hill. In the Holborn Station, the back portion of the building is occupied
by three boilers, each of which can be worked up to a pressure of 30 lbs.
per square tnch. As a rule, only one boiler will be worked at a time,
though all three can be used, if necessary. Between the boiler-room and
the arrival and departure platform is the engine-room, fitted with two
twenty-four horse-power engines, which work the shaft of the circular disk
or fan, twenty-four feet in diameter. This, revolving rapidly upon its axis,
having inclosed air-chambers, can be used either for propelling the laden
trains forward by atmospheric pressure behind them, or for drawing them
back through the tube by forming a partial vacuum before them.
The trucks of goods, accompanied by one of the attendants, were blown
through the tube to Euston in about five minutes, showing the ease with
which a portion of the goods and parcels traffic of the metropolis will
shortly be conducted. Wheatstone's telegraphic apparatus is used at the
stations, and is found to act well. In the station there are two main lines
of rails and three sidings, the distance between the rails being three feet
eight and a half inches. There are also two traversing platforms for shifting the trucks from one part of the station to another. The Duke of Buckingham, the chairman, and some of the directors of the company, were
blown from the Holborn Station, under the supervision of Mr. Rammell,
the engineer, through the tube to Euston, the distance being accomplished
in five minutes.
OPENING OF THE EXTENSION OF THE PNEUMATIC DISPATCH IN LONDON.
(See Figure 2.)
[From "Frank Leslie's Illustrated Newspaper," Feb. 17, 1866.]
THE system of conveyance by atmospheric propulsion through a tube,
which was lately exhibited in the grounds of the Crystal Palace, England,
and had previously been tried on the short experimental line at Battersea,
as well as in the neighborhood of the Euston Square Station, in Seymour
street and Eversholt street, Camden Town, has now obtained an important
practical extension by the opening of the line from Euston Square to Holborn, a distance of one mile and three quarters, whence it will be continued
another mile eastward to the General Post-Office, St. Martin's-le-Grand.




THE PNEUMATIC DISPATCH.                      17
The premises, No. 245 Holborn, which are the present terminus of the line,
are well worthy of a visit of inspection.
Entering from the level of the street, the visitor passes along a corridor
through a doorway, and emerges upon a gallery of considerable size, from
which he looks down on a brick floor, supporting lines of rails, much as he
might do from a railway platform down on to the line, but from a greater
elevation. Underneath the corridor by which he has just entered he sees
some mechanical appliances, suggestive partly of an engine-room and partly
of a pointsman's gallery outside a railway station; and below the level,
again, on which the white-jacketed engineer in charge is standing, and
supporting the platform on which both he and these mechanical appliances
rest, are a couple of openings, looking like black, polished modern chimney-pieces with the grates withdrawn. These are the mouths of the pneumatic tubes, of which one communicates with the North-Western Railway;
the other, idle at present, will soon be drawing in and delivering mail-bags
from and to the postal headquarters in London. The mouth of each tube
is shut, when the tube is exhausted by air, by iron folding doors, which
meet, not evenly, but at an angle projecting outward, so as to resist the
atmospheric pressure from without. These doors are made to fly open on
the approach of the train, the bolt which closes them being withdrawn by
the action of a spring-lever, which underlies the rails, and gives way beneath the weight of the train. The carriages are shaped like a capital D
turned over on its straight side and mounted upon wheels. Each end of
the carriage has a raised hood, or flange, shaped so as to correspond with
the interior of the tube, the dimensions of which are four feet in height by
four feet six inches in width. Their ordinary freight is expected to be, in
the first instance, letter-bags, then probably railway parcels, certain descriptions of market produce, and, ultimately, it may be, general merchandise.
On the opening day the Duke of Buckingham, Chairman of the Pneu
matic Dispatch Company, had invited a number of scientific gentlemen to
inspect the apparatus. After the train had made some successful passages
to and fro, several of the party expressed a strong desire to pass through
the tube themselves. They were warned that the line was "not constructed with a view to passenger traffic," and that they might find the
way "a little rough."  The spirit of adventure, however, prompted them
to take this strange journey, and each of the wagons had soon as many
occupants as it could comfortably accommodate in the recumbent posture
enforced by circumstances. Tarpaulin coverings were obtained for one or
two of the carriages, but the greater number of the excursionists had to fit
themselves in as best they could among the bags of shingle which made up
the temporary loading, taking care to keep their heads well below the edge
of the carriages.
The air within the tube was by no means foul or disagreeable; here and
there a strong flavor of rust was encountered; but this was explained by
the fact that, as the tube had to be laid in lengths, through various soils,
and encountered in the process a large share of unfavorable weather, the
corrosion on the surface of the iron could not be expected wholly to disappear until cleared away by the friction of constantly passing and repassing
trains.
On the arrival of the excursionists at the upper or Euston Square ex —
tremity of the line, they quitted their places for a few moments to inspect
the smaller tube, which communicates with the Eversholt Street District
Post-Office, and then returned by the way they had come to Holborn.
No doubt remained on the mind of any person who witnessed the opening trip as to the facilities which the system, if a sufficient number of sta



18                  THE PNEUMATIC DISPATCH.
tions can be incorporated with it, is calculated to afford, not only to the
postal service, but to the requirements of the general public. The scheme
of the company, who, it seems, possess under their act powers to lay down
pneumatic tubes at any points within the jurisdiction of the Metropolitan
Board of Works, is to construct similar lines to that now opened between
the ten district post-offices and the General Post-Office, and between the
different railway termini and goods-depots in London, connecting with these
lines the six principal London markets and other important points.
For these purposes, it is calculated that some thirty-five miles of tubing
will be required. The company expect that great profits will eventually accrue to them from the carriage of goods.
CHAPTER III.
THE EARLY ATMOSPHERIC PASSENGER RAILWAYS-OPENING OF THE FIRST
PNEUMATIC PASSENGER RAILWAY AT SYDENHAM IN 1864-GREAT SUCCESS OF THE ROAD-PARTICULARS CONCERNING TIHE TUNNEL BLOWING
MACHINERY, AND PASSENGER CAR-INCLINES EASILY ASCENDED STEEPER
THAN THOSE OF ANY OTHER RAILROADS.
[From the London "Mechanics' Magazine," Sept., 1864.]
ATMOSPHERIC RAILWAYS.
EXACTLY fifty-four years ago, a Mr. Medhurst proposed that a brick tunnel should be built and applied to the conveyance of passengers, at speeds
never more than dreamt of before. Within the brick tunnel a pair of rails
were to be laid, and on these rails a suitable vehicle, very similar in its
general arrangements to an ordinary railway carriage, was to travel. The
cross section of the brick tube, as proposed, would have been egg-shaped,
with the maximum width above. The rails would have rested on projections springing from the side walls near the bottom. To the rear of the
carriage, a piston, so to speak, formed of boards suitably framed together,
would have been affixed. This piston would have nearly fitted the tunnel.
Whether any expedients were proposed by which the space between its
edges and the brick-work could be made partially air-tight, we are not prepared to say. It is not likely that a scheme so perfect in principle as this
was would be found wanting in detail. The carriage and piston thus provided, and put in place within the tube, air was to be forced in behind by
means of a large pumping apparatus, very similar, we believe, in general
design, to the blowing engines at present used at our iron-works.
The pressure of the air thus pumped in would, it was contended, prove
sufficient to propel the carriage with its load of passengers at very high
speed.
Medhurst lived before his time. The scheme never got beyond a model,
for obvious reasons. In the first place, the steam-engine was not yet perfected, and the obtention of the necessary motive power for the blowing
machinery was by no means easy. In the second place, people had a very
great and perhaps natural antipathy to the idea of being placed within a
tube, dark and cheerless, and blown to their destination; and thus a really
valuable invention fell to the ground. It is easy, however, to see that Medhurst's was no ordinary mind. In this scheme we have the embodiment
of nearly all that constitutes the modern railway; the iron rails, the high
speeds, the accommodation for passengers, have a great deal in common




I
JoJ.al on*don an'2c2 Cr{h~



20                   THE PNEUMATIC DISPATCH.
with the present system of locomotion, and all this, be it olbserved, was
designed twenty years before the Rainhill trials inaugurated the railway
system.
After Medhurst came Vallance and Pinkus, who had no better success
than Medhurst, and it remained for Messrs. Clegg and Samuda, years afterward, to develop the system on a practical scale on the London and Croydon, and Dalkey and Kingstown Railways. (See Figure 3.)
The atmospheric principle as tried on these lines is now well known to
be wholly unsuitable to the demands of an extensive traffic, and, as far as
the country is concerned, the vacuum-tube and the piston-carriage have
been banished forever in favor of the locomotive. With the introduction,
however, of the underground metropolitan railway system, the old scheme
of Medhurst bids fair to be revived. Indeed, there is hardly room to doubt
that it is, of all others, the most suitable for the exigencies of this species
of traffic. In the pneumatic dispatch we have, on a small scale, all that
Medhurst proposed; and there can be no room to doubt, from the success
which has already attended upon the labors of the company, known by the
same name, that the system can be extended to the conveyance of passengers without any practical difficulty whatever.
During the last few months, too, Mr. Rammel, the inventor of the pneumatic dispatch scheme, has been laboring at the Crystal Palace to provide
a model line, the first on which regular passengers have been conveyed,
which would serve to bring all these advantages fairly before the public.
(See Figure 4.) The tube extends from the Sydenhamn entrance, to the armory
near Penge-gfate, a distance of about a quarter of a mile, and it is, in fact,
a simple brick tunnel, nine feet high and eight feet wide, a size that renders it capable of containing an ordinary Great Western Railway carriage.
That actually working in the tube at this moment is handsome and commodious. The piston is rendered partially air-tight by the use of a fringe
of bristles extending nearly to the brick-work of the tunnel and its floor.
A fan twenty feet in diameter is employed to exhaust or to force in air,
and perhaps it is impossible to devise any other expedient so well calculated to answer the required purpose. It must be remembered that either a
pleuum or a vacuum equivalent to five tenths of an inch of mercury is quite sufficient to propel even a heavy train at a high speed on a moderately level
line. In the present instance the motive power is supplied by an old locomotive borrowed from one of the railway companies, which is temporarily
mounted on brick-work. The tires have been removed from the drivingwheels, and these last put the fan in motion by straps. The line, we have
said, is a quarter of a mile long; a very small portion of it, if any, is level,
but it has in it a gradient of one in fifteen, an incline which'no engineer
would construct on an ordinary railroad; and as it is not a level line, so
it is not a straight one; for it has curves of only eigiyt chains radiues, which
are shorter than those usually found in existing railways. The entire distance, six hundred yards, is traversed in about fifty seconds, with an atmospheric pressure of but two and a half ounces. The motion is of course easy
and pleasant, and the ventilation ample, without being in any way excessive.
All the mechanical arrangements are so simple and must be so obvious, we
imagine, that it is needless to dwell on them. We feel tolerably certain
that the day is not very distant when metropolitan railway traffic can be
conducted on this principle with so much success, as far as popular liking
goes, that the locomotive will be unknown on underground lines.




ethical~~~~~~~~~~~~~~~~~~~~~~~~~~~~~1
pdedae at 8ydenhl
Tiq  4  i iew of the Pzi ~~~~~~~'t P~~eu~~natzee  e Car and  Thnias 0pe




22                    THE PNEUMATIC DISPATCH.
THE PNEUMATIC RAILWAY IN THE GROUNDS OF THE CRYSTAL PALACE.
[From the London "Illustrated News," Sept. 10, 1864.1
WE give an illustration of the Pneumatic Railway, which has been put
in operation during the last two weeks, in the grounds of the Crvstal Palace. It extends from the Sydenham entrance to the armory, near
the Penge-gate, a distance of nearly six hundred yards. A brick-work tunnel, about ten feet high by nine feet wide, and capable of admitting the
largest carriages used on the Great Western Railway, has been laid with
a single line of rails, fitted with opening and closing valves at each extremity, and supplied with all other apparatus for propelling passenger
trains on this principle-by a strong draught of air behind the train when it
travels in one direction, and pumping away the air in front of it when it
travels the other way. The motive power is supplied by this contrivance:
at the departure station a large fan-wheel, with an iron disk, concave in
surface, and twenty-two feet in diameter, is made to revolve, by the aid of
a small stationary engine, at such speed as may be required, the pressure
of the air increasing, of course, according to the rapidity of the revolutions, and thus generating the force necessary to send the heavy carriage
up a steeper incline than is to be found upon any existing railway. The
disk gyrates in an iron case resembling that of a huge paddle-wheel; and
from its broad periphery the particles of air stream off in strong currents.
When driving the air into the upper end of the tunnel to propel the downtrain, fresh quantities rush to the surface of the disk to supply the partial
vacuum thus created; and on the other hand, when the disk is exhaustingthe air in the tunnel with the view of drawing back the up-train, the air
rushes out in a perfect hurricane from the escape-valves of the disk case.
When the down journey is to be performed, the breaks are taken off the
wheels, and the carriage moves by its own momentum into the mouth of
the tube, passing in its course over a deep air-well in the floor, covered
with an iron grating. Up this opening a gust of wind is sent by the disk,
when a valve, formed by a pair of iron doors, hung like lock-gates, immediately closes firmly over the entrance of the tunnel, confining the increasingr atmospheric pressure between the valve and the rear of the carriage.
The force being thus brought to bear upon the end of the train, the latter,
shut up within the tube, glides smoothly along toward its destination, the
revolving disk keeping up the motive power until it reaches the steep incline, whence its own momentum again suffices to carry it the rest of the
distance. The return journey, on the contrary, is effected by the aid of the
exhausting process. At a given signal the valve is opened, and the diskwheel set to work in withdrawing the air from the tube.  Near the upper
end of the tube there is a large aperture, or side-vault, which forms the
throat through which the air is exhaled, the iron doors at the upper terminus still being kept shut. In a second or two the train posted at the
lower terminus, yielding to'the exhausting process going on in its
front, and urged by the ordinary pressure of the atmosphere from
behind, moves off on its upward journey, and, rapidly ascending the
incline, approaches the iron gates, which fly open to receive it, and it
emerges at once into daylight. Instead of a train being used at Sydenham,
there is one very long, roomy, and comfortable carriage, resembling an
elongated omnibus, and capable of accommodating some thirty or thirtyfive passengers. Passengers enter this carriage at each end, and the entrances are closed with sliding glass doors. Fixed behind the carriage
there is a framework of the same form, and nearly the same dimensions, as
the sectional area of the tunnel, and attached to the outer edge of this frame




THE PNEUMATIC DISPATCH.                    23
is a fringe of bristles forming a thick brush. As the carriage moves along
through the tunnel, the brush comes into close contact with the arched
brick-work, so as to prevent the escape of the air. With this elastic collar
round it, the carriage forms a close-fitting piston, against which the propulsive force is directed. Although the curve in the tunnel is unusually sharp,
being of eight chains radius, and the gradients are as high as one in fifteen,
(those of Holborn Hill being only one in eighteen,) it is surprising that
the motion is much steadier and pleasanter than ordinary railway traveling.
The journey of six hundred yards is performed either way in about sixty
seconds, with an atmospheric pressure of only two ounces and a half to the
square inch; but a higher rate of speed, if desirable, can easily be obtained.
CHAPTER IV.
INCORPORATION OF THE WHITEHALL PNEUMATIC PASSENGER RAILWAY-THE
RAILWAY TO EXTEND FROM CHARING CROSS UNDER THE THAMES RIVER
TO THE SOUTH-WESTERN RAILWAY-DESCRIPTION OF THE UNDERGROUND
TUNNEL-DETAILS AND VIEW OF ONE OF THE SUB-AQUEOUS PNEUMATIC
TUBES-PECULIAR METHOD OF CONSTRUCTION AND LAYING OF THE TUBES
— SECTIONAL VIEW OF THE THAMIES RIVER EMBANKMENT, SHOWING PASSAGE UNDER IT OF THE PNEUMATIC RAILWAY TUBE —PNEUMATIC VS. LOCOMOTIVE RAILWAYS-PNEUMATIC RAILWAYS IN SWITZERLAND.
[From the London " Mechanics' Magazine," June 16, 1865.]
WHITEHALL PNEUMATIC RAILWAY.
WHEN railways first began to invade London, they were met on the
threshold by the prohibitory injunction, " Thus far and no farther."  Not a
foot might they advance beyond the suburbs, be the necessity what it might.
The great point was to compel all railway companies to keep their termini
at a respectful distance from the metropolis proper. The citizens' territory
was to be sacredly protected against the intrusion of the iron horse, and
the royal prophecy, that the map of London would one day be marked with
railways as with a gridiron, was to have no fulfillment in fact. But matters
have changed since those days, and there is now a growing conviction that
the metropolis must be provided with railway accommodation throughout
its length and breadth. The establishment of one line led to the construction of a second and a third; and for the birth of how many more during
this session we may consider these responsible, we know not yet. But the
construction and working of railways in the metropolis must be based upon
principles differing widely in the main from those most familiar to us in
other lines. In London railways can not be otherwise than a nuisance if
overhead, on the ground-level, or in open cutting. Under any of these conditions they are open to many objections, and are in fact inadmissible.
Their proper and only place must, therefore, be in tunnels, out of sight and
hearing. The general conditions of construction being determined, it remains to decide the method of working. Now, it is certain that tunnels
can never have proper ventilation, or passengers pure air, so long as the
generation of steam is proceeded with upon the line. The fire-box of the
locomotive must be sacrificed to begin with. To do this it has been proposed to use an engine containing the necessary volume of water, heated
sufficiently to produce the requisite quantity of steam to work, for a given




24                   THE PNEUMATIC DISPATCH.
distance, without any combustion or generation of gases in the tunnel.
But the boiler has yet to be made by which this idea shall be effectuated.
Even were this accomplished, there would still be the highly objectionable
waste steam blowing off into the atmosphere, saturating it with moisture,
and condensing on the surface of the tunnel. But another engineer steps in,
and recommends the waste steam to be blown into a cast iron pipe between
the rails, and therein condensed. But while such plans are maturing, and
pending the practical realization of these and similar ideas, let us see to
what extent we can avail ourselves of other sources of power-how far we
may travel independently of the direct action of fire and water, under conditions where, as sources of motion, they are clearly inadmissible.
It is an old notion, and by no means an erroneous one, that the power
acquired by atmospheric pressure would realize greater safety, economy,
and expedition than that obtained by the ordinary locomotive. The trial
of the system of atmospheric propulsion for fourteen years, on the line from
Paris to St. Germain, bears witness to the absolute security attending its
adoption. We have also had practical experience in this direction on some
of our own lines. But the system has failed, and this has been due to the
imperfect manner in which it has been carried out. Notwithstanding all
that was done to develop the principle, it had to be abandoned, not from
any inherent fault or fundamental error in the principle itself, but because
the details of its application were not sufficiently mastered to render it a
practical success. To insure the effectual working of the atmospheric system, tunnels and a piston-carriage must be substituted for the old arrangement of tube and traveling-piston; such a system of working, for instance,
as that in operation on the experimental line at the Crystal Palace. Here
a power has been developed by which trains have ascended inclines inaccessible to the ordinary locomotive. This result is obtained from the pneumatic system which differs materially from the former atmospheric system.
By the new method, the train is wholly within the tunnel or tube, by which
arrangement all the difficulties attendant upon working the continuous valve
are entirely overcome. Leakage is thereby avoided, and a considerable
further advantage is obtained in working at reduced pressures, and with
proportionate economy.
With the old arrangement, a pressure ranging from one hundred and
twenty to one hundred and sixty ounces per square inch was required to
move the train, but under the new conditions a pressure of not more than
three or four ounces per square inch is all that is necessary. In the Crystal
Palace tube, the train is moved through a tunnel having an area of eighty
or ninety square feet, at the rate of thirty or forty miles per hour, by a pressure of only two and a half ounces on the square inch. This propulsion is
simply due to the pressure of the air behind the train, so that, in effect, the
pneumatic system is but a modified application of the process of sailing to
railway trains. The practical utility of this system has been proved, noL
only by the successful working of the trial passenger railway at Sydenhanm,
but also by that of the Pneumatic Dispatch Company. It is now to be
further tested on a practical working scale, upon a railway about to be made
from the Waterloo station across, or rather through, the bed of the Thames
to Charing Cross. The bill for this line has not yet been obtained, it is true,
but it has passed the House of Commons, and is unopposed in the Lords,
so that for all practical purposes it may be acted upon as though it had received the royal assent.
The importance of this system of working railways, and the novel position of the line, justify somewhat more than a passing glance at the engineering arrangements, which will be carried out under the direction of Mr.
T. W. Rammell, engineer to the Pneumatic Dispatch Company, and with




THE PNEUMATIC DISPATCH.                    25
whom Sir Charles Fox & Son are joint engineers. The new system affords
great facility for communication under water. Taking advantage of this,
it is proposed to lay a line of tube in the bed of the Thames, so as to unite
the north and south sides of the river, between the two points embracinig
the important localities of the Charing Cross and the South-WVestern Railway stations. According to the Parliamentary plans, the line will commence in Great Scotland Yard, where there will be an open station, the
level of rails being here about sixteen feet below surface. It will be carried thence by a brickwork tunnel under the Thames embankment to the
river, which at this point is about one thousand feet wide. Here the line
will be continued by water-tight wrought iron tube, about eighteen feet in
diameter, which will be made of three fourth inch plate, and girt at about
every thirty-six feet with a deep wrought iron rib, to which will be connected lighter longitudinal ribs, also of wrought iron. The tube will be
further surrounded by light ribs of T or L iron, placed intermediately between the larger encircling ribs, the whole forming a stiff network to
strengthen and stay the tube. The outer surface of the tube will be coated
to the thickness of eighteen inches with concrete, for the purpose of adding
weight to the tube. By this plan it will be brought to about the specific
gravity of the surrounding water, and the ironwork will also be protected.
The bed of the river will be divided into four spans, of two hundred and
fifty feet each, by means of three sunk cylinder piers; there will also be two
abutment piers. These piers will carry the tube, which is about to be manufactured in four lengths, of two hundred and fifty feet each. A perfectly practical and satisfactory arrangement has been made for connecting the ends of
the tubes, which will be tied down to the piers. Messrs. Samuda have
undertaken the manufacture of the tube, and to Messrs. Brassey have been
entrusted the laying and other incidental works. From the abutment pier
on the Lambeth side the line will be continued in brickwork under College
street and Vine street, to a station convenient for the York road and
Waterloo station traffic. The gradients fall from either station to the centre of the river, at which point the line is level for a short distance; the
steepest gradient will be about one in thirty.
It will be seen that the line is intended for local traffic only, and it is
proposed, upon the success of the first section being established, to extend
the line on the one hand to the Tottenham Court road, and on the other to
the Elephant and Castle.  This will add ten-fold to the value of the line,
by bringing it into close communication with the Metropolitan Underground Railway at one end, and the Metropolitan Extension of the London,
Chatham, and Dover Railway at the other. The engine-house will adjoin
the station at the Waterloo end, where will be placed the pumping-engine
for working the line. Although only one main tube is to be used, arrangements have been made by which three trains will be kept working at once.
One will be at each station unloading or loading while the third is traversing the line, the time of transit occupying only about a minute and a
half. By means of two branch tubes from the main tube to the engine,
trains will be driven by pressure to Whitehall, and drawn from thence by
exhaustion. The carriages will, of course, be properly lighted and comfortably fitted, similarly to those on the Metropolitan Railway. It is reckoned
that about thirty trains per hour will be run, and, from calculations based
upon well-ascertained data, there appears to be every probability that the
undertaking will prove a commercial as well as an engineering success.
It can not be questioned that the pneumatic system possesses many advan.
tages over the locomotive system, which specially recommend its adoption
on the Waterloo and Whitehall Railway. If this line proves a success, and
at present there appears no reason why it should not, the system will,




26                   THE PNEUMATIC DISPATCH.
doubtless, receive a very widely-extended application. It presents economical features, both in construction and working, not obtainable by any other
plan. The diameter of the pneumatic tube being less than that of a railway
tunnel, the lines can be constructed with greater expedition and at a less
cost. The heavy expenses attending the acquirement of property are
greatly reduced, if not entirely avoided. In the case of the Whitehall line
the construction will not involve the demolition of a single dwelling-house,
the entire line passing under streets and open spaces. The working of the
system, too, is comparatively noiseless; this, and the freedom from vibration, recommend its use where a locomotive line would be prohibited. The
dead weight and encumbrance of the engine and tender are at once got rid
of, and the service thus rendered more prompt and better adapted to the
exigencies of a short local traffic. All the dan'gers attending the locomotive
system, arising from breaking down, collision, or explosion, are necessarily
absent; trains can neither leave the rails nor meet within the tube. The
system also complies with the conditions laid down as those under which
alone tunnel lines ought to be worked. It is unattended by the objectionable compound of stifling and humid vapors which Mr. Fowler's best precautions can not entirely prevent on the Metropolitan Railway. Not only
is the generation of gases avoided, but the tunnel is completely ventilated
by the continuous draught of air through it. The motive power being stationary, the working expenses and cost of maintenance of the line will be
very much less than under the ordinary system; the wear and tear of rolling stock may likewise be reduced to a minimum. The facility with which
steep gradients and sharp curves can be worked is evinced by the Crystal
Palace tube, which is constructed with a gradient of 1 in 15, and curves of
8 chains radius; on the Whitehall line the worst gradient is about 1 in 30.
Such, then, are the leading advantages of the pneumatic system, the working of which is about to receive practical illustration in a position where
there are doubtless thousands daily, who would much prefer being whisked
across in a minute and a half, for a penny or twopence-which we believe
are the proposed fares-to making a long detour over either of the bridges.
Deducting the halfpenny toll payable on Waterloo and Hungerford bridges
practically reduces the fares to a halfpenny and three halfpence respectively.
Although the engineering details have been well digested and worked out,
and every care has been taken to perfect the arrangements, it may be found
advisable to vary or alter these as the work of practical construction proceeds under these novel conditions. But the principle will remain the same,
and to it we look with considerable hope for the future working of short
lines for local traffic in the metropolis.
[From the London Correspondence of " New-York Herald" of 5th of February, 1865.]
THE PNEUMATIC DISPATCH-LOCOMIOTWVE POWER.
CONSIDERABLE attention is now being paid to the best means of carrying
on the enormous passenger and goods traffic of London. The conclusions
almost universally arrived at are, that the great bulk of it must be done by
pneumatic propulsion.  Recent scientific experiments have demonstrated
that the locomotive uses less than one tenth of its power in railways that
have as frequent stoppings as necessary in a city like London.  It is
wasted in the friction caused by overcoming the inertia of starting the
trains and getting up the speed, and then in stopping.  A train ordinarily, on a long line, can not get fairly up to its normal speed without
running from a mile and a half to four miles, while in or under cities they
must stop every third or half of a mile. In a very elaborate and interesting




THE PNEUMATIC DISPATCH.                    27
paper, read before the Society of Arts last week, it was demonstrated, or at
least stated, that in a locomotive power of twenty-two hundred horses, on
city railways, the power actually used in propelling the train was only that
of two hundred and fourteen horses. The paper was not on the subject of
the pneumatic power, but on power generally for the purposes of city traffic.
But the great loss of power attending the use of locomotives was illustrated
in pneumatic propulsion. In the locomotive, the train is drawn by the friction, or "bite," of the wheels of the engine on the rails. But in the pneumatic propulsion, where the air is the motor, it may be said, by a mythological figure, that /Eolus, the God of the Winds, draws the trains, or
pushes them, by his ethereal breath, while on the wing, with no foothold on
the earth whatever, and none required. The Metropolitan (underground)
Railway, from Paddington to the city-some three miles long-now carries
sixty-four thousand passengers daily-a line about as long as from the South
Ferry to Madison Square, up Broadway. The receipts of this short railway
are now ~2600 ($13,000) weekly, or about ~150,000-say $750,000, gold,
annually. But the traffic is not yet anywhere developed. The line stops
at least a mile and a quarter from the Bank and Royal Exchange, and runs
over a route that is neither a great thoroughfare nor that contains a large
resident population. A bill is coming before Parliament to make a line
across the river-tunneling the Thames again-near the Houses of Parliament, from the proximity of Charing Cross to the Waterloo Station-the
terminus of the South-Western Railway-running to Southampton. This is
for a pneumatic line. At Liverpo-ol they are agitating the tunneling of the
Mersey. So, after an uninterrupted and prosperous reign of nearly forty
years, that useful servant, the locomotive, or "steam-horse," stands some
chance of being superseded by a more powerful motive monarch. It will
not be the first time that a reigning sovereign, on growing old, has had to
give way before a younger and more vigorous aspirant and rival. Science
will never be stopped in her onward progress, no matter what interests get
crushed by her powerful wheels.
THE SUB-AQUEOUS PNEUMATIC DISPATCH —WHITEHALL PNEUMATIC RAILWAY.
ONE of the new passenger lines on the Pneumatic Dispatch plan, now
being laid down in London, is to extend underneath the river Thames. The
river is to be passed by means of wrought iron tubes, thirteen feet in diameter, covered with brickwork, and made in sections of 221 feet each. The
tubes are built upon stocks and launched like a ship, floated over the place
where they are to rest and then submerged. We herewith present an engraving of one of these tubes, from a photographic view, as it appeared a few
weeks ago, except the brickwork, which had not then been put on. Through
this tube any of the ordinary English railway cars can be driven by atmospheric pressure. The Scientific American of February 16th, 1 867, in an interesting article upon Bridges and Tunnels, thus speaks of the work above
mentioned:
"Some of the expedients proposed by English and American engineers for
locating tubular tunnels under water may here be mentioned. The first in
prominence, at present, is the plan adopted for sub-tubing the Thames in
London. The tube of the Waterloo and Whitehall Pneumatic Railway is
to be built in four sections or spans of 221 feet each, supported not merely
along the length of the tube in a dredged channel, but also upon piers going
down to the clay. The tubes, now in course of construction by Messrs.
Samuda, at the Isle of Dogs, are of three quarter inch iron, with three rings
of enveloping brickwork bound by hoops of angle iron, and are to receive,
after being laid, an internal lining of brickwork, bringing their diameter to




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THE PNEUMATIC DISPATCH.                     29
twelve feet nine inches. The length of the tubes, including shore ends, will
be five eighths of a mile. The ends of each section are closed by bulkheads,
and when finished all will be floated down to Hungerford, and by a moderate admission of water will be eased down into exact position in the trench
and on the foundations prepared for them.  The ends will be brought into
connection as lowered, by means, we presume, of guiding rods on the one
entering corresponding holes on the other, and a close joint will be effected' by means of an ingenious water-tight lock or stuffing-box, devised by Mr.
Rammell.' From which language of our English authority on that point
(Engineering) we understand that the ends are to interlock, with suitable
packing, in some way that will result in a water-tight joint for purposes of
construction. It is evident that a packed joint could be forced home, without any required power, by the simple exhaustion of air from the shoreward
section. The bulkheads can then be removed, and the joint secured and
packed permanently, by means of inside flanges, ready bored with matched
bolt-holes. Indeed, supposing the nearer flange to be inside the bulkhead,
and the holes in the opposite flange to be threaded, the bolts might be
inserted through without removing the bulkhead, if thought necessary or
more prudent. Then, cutting away the bulkhead, the annular space between the flanges could be packed impenetrably, at leisure, or, if needful, in
haste.
"This is very likely the simplest and least expensive mode of joining
the tubes at moderate depths. Others, however, have been suggested, and
we shall mention last a suggestion of much promise for sub-tubing the
Straits of Dover. Such things have been proposed and discussed since as
long ago as 1809. Half a century is not an excessive period to elapse between the first suggestion of a great improvement and the first serious
attempt to realize it. One of the best plans offered in the past was to build
a wooden coffer-dam for a section of the work, by one of the variety of
methods in use; commencing at the shore, and having either excavated and
lined with masonry a tunnel in the river bed, or laid a tube of wrought or
cast iron, or wood, and fully imbedded it in loose rock and earth, then
cross the dam with a bulkhead, or new end near the termination of the finished work, and thence-removing the portion now done with-extend the
dam forward to inclose a new section of the work to be done. This, being
substantially a well-tried system, and affording clear space and leisure for
the most thorough foundations, superstructure, and leveling, will commend
itself to careful consideration; especially if the danger of forming a bar in
the harbor should compel the constructor to sink his work wholly beneath
the bed of the river."
[From the London " Mechanics' Magazine," November 17, 1865.]
PNEUMATIC VERSUS LOCOMOTIVE RAILWAYS.
THE accomplishment of the longest distance in the shortest time is the
great mechanical problem of the present age, which theoretically aims at
the virtual annihilation of time and space, whether relating to the transit
of words, materials, or individuals. With respect to the first of these, the
electric telegraph has not only theoretically, but we may even say practically, accomplished the solution of the problem. The steps made toward
accelerating the transit of the second and third are measured by the aver.
age maximum speed attainable on our railways by the goods and passenger trains. For some years back there has literally been no progress made
on our railways. By progress we do not mean the mere extension of the
railway system, or the multiplication of lines over the kingdom, and, in fact,




30                   THE PNEUMATIC DISPATCH.
over the whole world in general, but that increase of speed which we are
now entitled to expect, should have taken place since the introduction of
railways, but which certainly has not. When Stephenson, in the first competitive trial of locomotives, carried off the prize of ~500 with the " Rocket,"
he drove it for a portion of the way at the rate of twenty-five miles an
hour; and every railway traveler is well aware that the ordinary passenger
trains do not even reach this.
It is evident, with respect to the speed attainable on our railways, that
we now, and for some time past, have reached a climax, and are precisely
in the same comparative position as the old mail coaches, when they
reached a speed of about eight or nine miles an hour. There they stopped,
and there they would have stopped until the end of time. So it is with
our railways. A certain speed has been reached-say, a maximum of fifty
miles an hour and no more. Nor will a higher velocity be obtained on our
present lines, or on any others constructed in a similar manner, and on
what now seems to be the orthodox principle, which entails the adoption
of sharp curves and steep inclines as an indispensable accompaniment of
railway construction. It is not that the necessary motive power could not
be obtained, for, leaving out of consideration the enormous expenditure
and the questionable nature of the advantages attendant on a large increase
of locomotive power, any degree of speed might be produced, but the manner in which our lines are constructed does not admit of more than a certain speed consistent with safety. That speed has been already attained,
and it is in vain to suppose that a higher one can be reached on any line
constructed on the present system. If, then, the locomotive principle is to
be adhered to in our future railways, the roads themselves must be altered
before that degree of speed is attainable which will, before long, be demanded by the exigencies of modern advancement. It is worthy of remark
that when railways superseded the mail coaches, the first operation necessary, before the improved method of locomotion could be introduced, was
the alteration of the road on which the locomotion was to be conducted. We
do not at present propose to enter on a subject so vast and comprehensive
as the alteration of our present railways, in order to afford the desired velocity. There is another principle, namely, the pneumatic, which, although
only on its trial, gives fair promise of supplying the above desideratum.
The experiments made last year at the Crystal Palace have demonstrated,
beyond a doubt, that it is possible, in an engineering point of view, to apply the principle to passenger traffic. Nor will the cost be found to be so
excessive as is generally imagined. The first item, and often the most serious in the construction of a railway, is the purchase of the land. This
item is reduced to a minimum in a railway on the above principle, firstly,
because it is a continuous tunnel or tube, (although necessarily underground,)
and, secondly, because it admits of very steep inclines, which would have
the effect of reducing the cuttings and embankments to very insignificant
dimensions, and cause the line to approximate more to a surface line.  It
is not at first apparent why the pneumatic admits of curves which could
not obtain on the locomotive lines, for the resistance to be overcome is
the same. It is because, on the latter principle, the whole motive power is
directly affected by the construction of the road, whereas on the former it
is altogether independent of it. A locomotive consumes a large amount of
its power in moving itself, the expenditure of which increases rapidly in proportion to the gradients and curves. Leaving out of consideration the difference in expense between stationary and locomotive engines, the adoption
of the former will yet considerably reduce the cost of the permanent way.
It is asserted by the managers of iron-works that every additional order
they receive for rails is for a heavier description than the preceding ones.




THE PNEUMATIC DISPATCH.                     31
Rails of 80 lbs. and 90 lbs. to the yard are the only weights which will stand
the terrific pounding of the driving-wheels of an express engine, while
others of 50 lbs. and 60 lbs. would be sufficiently heavy for the traffic of carriages and wagons alone, and last very much longer.
In comparing the first cost of the two principles, we have thus at the
outset a direct saving, in favor of the pneumatic, respecting the important items of land, earth-work, rolling-stock, and permanent way, items
which are common to both. Against this, however, must be set the cost
of the peculiar construction of the pneumatic railway, of which the heaviest
portion is the tunnel or tube in which the carriages are conveyed. On the
supposition that the tube would be made of brickwork, the cost would not
exceed that of those portions of the metropolitan line which are continuous
tunnels. It is probable that it would fall within this amount, as, in consequence of the locomotive being dispensed with, less headway would suffice,
and thus the sectional area of the whole tunnel would be reduced, and a
corresponding saving effected in the quantity of material employed. In the
experimental trial at the Crystal Palace, quoted above, a headway at the
crown of the tunnel of ten feet allowed the largest carriages on the Great
Western line to pass. The least headway allowed on the South-Eastern Railway, from level of rails to soffit of crown of any arch, is thirteen feet six
inches, or about one third more. On the other hand, it is questionable
whether an iron cylindrical tube would not form the best inclosing medium.
It would possess decided advantages when the line crossed a river, supposing circumstances did not permit of its passing under the surface of the
water, for, being made additionally strong, it would elrve the purpose of a
bridge, not only in this particular instance, but wherever any intervening
space is requi.ed to be spanned. There is no necessity for the tube being
continually underground, as might be supposed, judging from the short
pieces of line constructed. In fact, it would be impossible that it should
be so in applying the principle to railways in general. The most advantageous cross-section of road would probably be a cutting just deep enough
to cover the tube all over, and so protect it from the influences of the
weather. We have before stated that, in consequence of the motive
power on the pneumatic principle being unaffected by the resistances of the
road, it will be able to afford a velocity greater than our present railroads
can give. It must not, however, be inferred from this, that steep inclines
and sharp curves are of no consequence on a pneumatic railway; for, no
matter what the motive power may be, they virtually put a limit, and a
most effectual one, to the speed which may be ultimately acquired. This
principle will soon be applied to a passenger line, the construction of the
Waterloo and Whitehall Railway having been recently commenced. The
promoters, however, should bear in mind that, unless the new railway gives
the public something which the present ones do not, there is no valid reason
for supposing that, when the novelty has once worn off, it will have any
advantage over those now in existence. Next to a lower fare ftiom one
place to another, there is nothing the public appreciate more than being
able to travel by the quickest way, and, in truth, the quickest way, although
it may in some cases be the dearest, provided the difference be not too
great, pays the best in the long run. Many a railway has been irremediably spoilt, and the dividends reduced almost to nil, by too great a
parsimony in the first cost. It is considered by some a clever piece of
financial policy to keep the first cost low by introducing heavy gradients
to lighten the expense of deep cuttings and embankments, and sharp curves
to avoid the purchase of houses and other property. When, however, the
profits of the line are swallowed up by the expenses attending the working of
these inclines and curves, and the cost for additional repairs of the rolling




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THE PNEUMATIC DISPATCH.                    33
stock and permanent way, the error becomes apparent, and the fallacy ot
such parsimonious calculations but too evident. In the construction of a
railway, like every thing else, the best way is the cheapest in the end, and
it is to be hoped that the promoters of the pneumatic passenger railway
will have a due regard to this fact when laying out their first line, and not
ultimately incapacitate themselves from developing a high velocity by any
inherent fault in the construction of their roads, which is unfortunately the
case with nearly all our present lines.
[From the " Scientific American," June 22, 186T.]
PNEUMATIC RAILWAYS IN SWITZERLAND.
M. C. BERGERON, Director of the Western Swiss Railways, has obtained
a concession from the Canton de Vaud to connect the railway station and
the Place St. Fran9ois, at Lausanne, Switzerland, by means of a pneumatic
railway.
The same engineer has lately presented to the British Association at
Nottingham the plans for a pneumatic railroad over the Alps, by the Simplon Pass, commencing in the Saltine Valley on the Swiss side, and the
Diveria Valley on the Italian side. The distance is sixteen miles. M.
Bergeron estimates the total expense at $4,000,000. The incline on the
Italian side would be 1 in 14; on the Swiss side, 1 in 61. He proposes a
tube large enough to receive carriages of the size of an ordinary omnibus.
The highest point to be reached is 6000 feet above the level of the sea. The
tube is to be cut in the form of a gallery in the side of the precipices, the
debris being allowed to fall into the torrent below. The air current is to
be produced by means of water-wheels, for which the streams furnish an
abundant power. This is by far the cheapest plan yet presented for effecting the passage of the Alps by railroad. Its economy is principally due to
the small area of the proposed tunnel. The working expenses would be
very light.
CHAPTER V.
THE PNEUMATIC DISPATCH IN THE UNITED STATES-PUBLIC TRIAL OF THE
FIRST PNEUMATIC RAILWAY AT THE AMERICAN INSTITUTE-MANY THOUSANDS OF PASSENGERS CARRIED-PARTICULARS OF THE CONSTRUCTIONFIRST PUBLIC EXHIBITION OF THE PNEUMATIC POSTAL DISPATCH-SUCCESS
OF THE AMERICAN IMPROVEMENTS FOR COLLECTING THE MAILS-PROPOSED
PNEUMATIC RAILWAYS-HEATING AND VENTILATING THE CARS-ELEVATED
PNEUMATIC RAILWAYS-DETAILS FOR THE COLLECTION AND DELIVERY OF
THE MAILS WITH GREAT EXPEDIL.ION BY MEANS OF THE PNEUMATIC SYS —
TEM.
[From the " New-York Times," September 16,1867.]
THE PNEUMATIC RAILWAY AT THE AMERICAN INSTITUTE.
IT would be indeed surprising if the inventive genius of this country
had continued to sleep while the progressive labors above detailed weregoing on in England. The matter of underground railroads has been
twice before the Legislature of this State, and last year two bills were presented, asking for the right to form a company, and the necessary charter
to enable it to run pneumatic tubes for mail-dispatching purposes through




34                   THE PNEUMATIC DISPATCH.
this city. These bills, like many others, died a premature death in Albany,
but with them did not die all hope in a successful future for the Pneumatists-if we may coin a short name for them for convenience' sake:. Charters were obtained in Massachusetts, Connecticut, New-Jersey, and Pennsylvania, and it is understood that two bills for New-York will be again
presented, with best guarantees of success, at the next session of the Legislature. In the meantime our spirited neighbor, Mr. Alfred E. Beach, of
the Scientific American, is the first in the field with his demonstration of
the practicability of pneumatic passenger locomotion, made on an actual
working scale. The splendid example of a pneumatic railroad now erected
at the American Institute Fair, and which will be in operation to-day, is
the project of that gentleman, and it is not too much to expect that this
enterprise will be duly appreciated, and in time rewarded.
In the construction of this great working model there are some peculiar
features which will call for explanation as we proceed in the description of
the construction as a whole. Besides the great tube for experimental passenger conveyance, there is a full-sized model of a Pneumatic Dispatch
with noticeable improvements, which we shall also have'to notice in this
article.
The tube of the passenger railway at the Fair is suspended along the
wall, and runs from gallery to gallery, a distance of one hundred and seven
feet. It is six feet in diameter and is constructed of wood. The shell is
but one and a half inches thick, yet it is claimed to be capable of immense
resistance. This peculiarity is obtained by a novel process patented some
time since by J. K. Mayo. The inch and a half in thickness is made up of
fifteen layers, or lamina, of veneer, laid upon each other transversely and
spirally, and joined together by cement. The grain of the woods thus
crossed and recrossed gives a structure of remarkable strength and power
of resistance to either blow or pressure.  The carriage for passenger conveyance is long enough to seat on either side, like the ordinary street-car,
ten persons. It is open at the top and sides, the latter rising sufficiently
high only to protect the passengers' backs from friction against the sides
of the tube.  The door is placed in the centre of the 0-shaped end which
forms the valve or piston when the door is closed. The wheels of the car,
four in number, rest on rails laid along the bottom of the tube, and project
through the bottom a few inches only, being all that is necessary. Tlhe
wheel attachments, and, with this exception, the wheels themselves, are ilmmnediately beneath the seats. This permits fall use of the space within the
tube, so that the carriage is just'as free from touching the bottom as the
sides. The motive power, placed at the northern end of the tube, consists
of a great fan, ten feet in diameter, inclosed in a wooden chamber which
formns one end of the tube. This fan is unlike any yet used. It is, in flict,
a screw propeller with eight blades, so constructed that the pitch of the
blades is not more than twelve inches. This fan is driven by an engine
placed near by, and will make, if necessary, two hundred revolutions per
minute. Turning in one direction it produces a vacuum by exhausting the
air from the tube and throwing it off through apertures in the chamber,
thus drawing the car at the other end rapidly toward it. When its motion
is reversed, the opposite result is of course produced; the volume of air
then taken fromn the surrounding atmosphere is poured in a resistless stream
against the piston or flange of the car, which flies before it back to its
starting place.




THE PNEUMATIC DISPATCH.                     35
THE PNEUMATIC POSTAL DISPATCH.
Mr. Alfred E. Beach also exhibits at the Fair a section of a postal dispatch through which a truck for the conveyance of mail-matter is drawn
or propelled in the same manner as above explained. A smaller fan is used
for this tube. The tube itself is square, as are the trucks which pass
through it.  In connection with this apparatus is an ingenious automatic arrangement showing how mail-matter, received at different post-office
depots along the route, may be kept separate and so delivered, and in like
manner can a correct delivery at each station of out-going mails be effected.
This is possibly the most interesting feature of this most attractive exhibition. (See Fig. 8.) The lamp-post rising from the middle of the tube represents a street depository, having in its base a pair of rotary letter-boxes.
Every time the car passes the letter-boxes one of these is turned, and its
contents drop into the passing car; when the car returns the other box is
operated and its contents collected in like manner. Thus, the car when
passing up-town collects all letters destined in that direction, having been
dropped into the receiver of the lamp-post; returning, the down-town letters are collected from their particular box, into which they have been
dropped advisedly from above.
PROJECTS.
On the success of these practical tests, under the auspices of the American Institute, no doubt will depend in a measure whether we shall have any
immediate realization of the several projects in view, including not only
the establishment of passenger traffic and the transportation of mail-matter, but the scarcely less gigantic one of sub-tubing the North and East
rivers, and thus uniting Jersey City and Brooklyn with New-York.
It is estimated that the actual expense of laying down pneumatic passenger tubes under the streets of the city in the best manner with iron
tubing, including the running stock and engines, would not exceed $100
per running foot, or $500,000 per mile, being much below the estimated
cost of an under-ground steam-car railroad. The pneumatic plan would,
doubtless, require a smaller tube than any other form, and, consequently,
less excavation would be required; and, since by actual experience it is
shown that it can describe the sharpest curve, the route would not be difficult of selection. The suspension of the tube at the fair illustrates the
practicability of an elevated road, and suggests that the tube might be readily placed on posts or on brackets projecting from the houses passing between-the blocks, or even running over the house-tops.
The estimated cost of laying down the pneumatic passenger railroad
tube under the East River is $200 per running foot. Estimating the distance at three thousand feet, this would give an outlay of $600,000. Assuming this to be correct, the contrast between this sum and the $7,000,000
which the great suspension bridge is to cost is startling. For the larger
sum it is claimed that a dozen or more pneumatic tubes could be laid down,
affording ample trans-river accommodation at every important point on
either river, connecting all the great leading thoroughfares of the sister cities.
It is further estimated that passengers by a through city tube could be
carried from the City Hall to Madison Square in five minutes, to Central
Park in eight minutes, to Harlem and Manhattanville in fourteen minutes,
to Washington tHeights in twenty minutes, and by sub-river to Jersey City
or Hoboken in five minutes, and to the City Hall, Brooklyn, in two minutes. And that this, if ever accomplished-which is by no means improba



36                   THE PNEUMATIC DISPATCH.
ble-ought to be done at rates of conveyance far below those now charged
for most uncomfortable transportation, it is only fair to conclude from the
comparatively limited outlay of construction anticipated.
The projected Pneumatic Postal Dispatch is of a very important and
comprehensive character. It is proposed to carry a pneumatic tube of
about two or three feet in diameter from the Post-Office up Broadway to
Forty-second street, with branches at Twenty-seventh street to the Harlem and New-Haven railroads, and a branch at Thirtieth street to the Hudson River Railroad. A tube is also to girdle the city, passing through
South and Washington streets, so as to touch all the ferries and such landings where mails arrive and depart, bringing these points into immediate
communication with the General Post-Office. Tubes are also to extend
through Chatham street, Bowery, and Third avenue, also along Broad,
Pearl, Canal, Grand, Bleecker, and Fourteenth streets, and wherever the
public requirements may need; all the sub-post-offices, of course, being
connected with the General Post-Office. Further, it is proposed to extend
the postal tube under the East River, or over the suspension bridge, if
constructed, to Brooklyn, and through the principal streets of that city;
also under the North River to Jersey City, where it will connect with the
Pneumatic Dispatch Company of New-Jersey, to whom, as before stated,
a charter has already been granted. By this company it is proposed to
extend their lines as soon as possible to the nearest important cities, probably Newark and Elizabeth. By means of such a network, no doubt the
mails of the suburbs and suburban cities would be delivered at headquarters with great rapidity. The postal cars, it is stated, could be run at the
rate of thirty miles per hour, including all delays at intermediate stations.
Thus, letters might be sent up-town as high as Forty-second street, and replies received, almost with the speed of telegraphic messages. The advantages to business men could not be over-estimated, assuming the successful
operation of such a project. At the present time we know that letters in
many cases must be deposited ten or twelve hours up-town prior to the
mail-closing hour down-town, so as to secure transmission by that mail.
Letters for the early mails must be deposited on the night before, or they
fail to go, and to send a letter up-town and expect an answer on the same
day would be to hope against hope. In this connection it is only necessary
to say that, in whatever respect a pneumatic dispatch would be of value as
a mail-bearer, it would also be valuable as a bearer of packages, and not
by any means its least important business would be the delivery of newspapers at the various depots for the sale of that most valued necessity and
luxury juncto in uno.
Leaving to the imaginations of our accomplished readers the pleasant
labor of converting, with all the material here afforded them, our confused
and crowded city, with its no less crowded water boundaries, into a terrestrial paradise, where easy locomotion on land, on water, beneath them both,
or in the air, can be enjoyed at will, we close this article, hoping, with
them, that out of this great field of promise we may some day soon pluck
flowers of comfort.
r[From " Frank Leslie's Illustrated Newspaper," Oct. 26,1867.]
THE PNEUMATIC DISPATCH.
WE illustrate from the American Institute Exhibition, at Armory Hall,
Fourteenth street, the Pneumatic Railway, and the Postal Dispatch, both of
which have been erected by Mr. Alfred E. Beach, of the Scientific American.
The first consists of a mammoth tube extending across the building from gal



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38                   THE PNEUMATIC DISPATCH.
lery to gallery, supported midway by iron loops pendent from the roof. The
tube has inside a track, upon which runs a light, open car, carrying a dozen
or more passengers, and making regular trips every two minutes. The tube
is lighted by glass windows in the roof. The motive power is an 2Eolor,
or blowing-wheel, having the form of a screw propeller, placed at one end
of the tube. Its revolution in one direction sucks the air, and with it the
car, into the tube. The reversal of the screw drives the air back against
the car and pushes it out. One end of the car is provided with a disk, or head,
which fits the tube like a piston and against which the air presses.
The distinguishing characteristic of the pneumatic system is, that the
car is propelled by the wind. The car moves with a velocity proportionate
to the wind-current produced by the blowing-wheel. Actual experiment
proves that there is no difficulty in driving the car at the rate of one hundred miles an hour.
The pneumatic system appears to be admirably adapted to the purposes
of rapid city transit, since the ventilation is perfect, and the fieedom fiom
all jarring and dust is complete. Mr1. Beach is indefatigably laboring to
accomplish its introduction here, and it is to be hoped that his efforts will
meet with due encouragement and reward. About seventy-five thousand
passengers have so far enjoyed the atmospheric ride, and it is expected that
more than one hundred thousand will have passed through the tube before
the close of the exhibition, about November 1st. As soon as the proper
legislative authority can be obtained, it is proposed to lay down tubes under
the principal streets and under the adjacent rivers, when, it is stated,
passengers will be carried fiom the City Hall, New-York, to Madison Square
in five minutes, Central Park in eight minutes, Harlem and Manhattanville
in fourteen minutes, Washingoton Heights in twenty minutes, Jersey City
or Hoboken in five minutes, City Hall, Brooklyn, in three minutes.
THE POSTAL PNEUMATIC DISPATCH.
An examination of the Postal Dispatch (Fig. 8) shows that the letters
deposited in the lamp-post boxes fall into the rotary letter-boxes at its base.
One of the boxes receives the up-town letters, the other those for downtown. Beneath the boxes, constantly running back and forth in a pneumatic tube, is the Postal Car-a box on wheels-which, as it moves along
touches and turns one of the boxes, so that its contents fall into the car;
on the return movement of the car the other box is turned, and its contents
collected into the car. Such, in brief, is the operation of the proposed Postal Pneumatic Dispatch. The model actually at work in the Fair makes
four collections of the letters every minute, or two hundred and forty collections an hour.
The Postal Pneumatic Dispatch is also the invention of Mr. Alfred E.
Beach, and is now for the first time brought to the notice of the public. For
the purpose of better illustration, our artist has shown the tube, with its car
and letter-boxes, in the relative positions they are intended to occupy in
connection with the sidewalk. It is proposed to lay down these postal
tubes through all the principal streets of the city, and to have the Postal
Cars ply through them, by atmospheric pressure, as often as once in ten
minutes. The method of propulsion is the same as that for the passenger
car. By means of this ingenious arrangement, all letters or packages deposited in any of the receiving lamp-post boxes belowx Forty-second street,
may be conveyed to the General Post-Office, or to any intermediate station, in
six minutes! Welcome!-right welcome!-say we, to the Postal Pneumatic
Dispatch!




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THE PNEUMATIC DISPATCH.                     41l
[From  the " Scientific American," Oct. 19, 1567.]
THE PNEUMATIC RAILWAY AND PNEUMATIC POSTAL DISPATCH AT THE
AMERICAN INSTITUTE.
THE most novel and attractive feature of the exhibition is by general
consent conceded to be the Pneumatic Railway, erected by Mr. A. E. Beach,
of the Scientific American, and every one visiting the Fair seems to consider himself specially called upon to visit, and, after actual experience, to
pronounce his verdict upon this mode of travelincg.
It is an interesting sight to stand at the mouth of the great tube and
observe the arrival and departure of the car with its loads of passengers.
The car fits the tube like a piston, and travels both ways with the utmost
regularity and steadiness. Nothing can be more gentle and pleasant than
the start and stoppage; no jerking or wrenching of any kind is observable,
and although the car is not provided with springs, it rides along very easily.
The tube is one hundred and seven feet in length, six feet in diameter, and
is composed of fifteen layers of veneers, laid and cemented in alternate
spirals, forming a total thickness of an inch and a quarter. This peculiar
construction gives great strength and rigidity. The car carries twelve
passengers, and its body is rounded on the same curve as the tube. Indeed,
the body was made of a section of the tube cut in halves and the ends
nnited, forming a long open cradle without roof, with seats on each side,
presenting the appearance of an omnibus sleigh. The wheels project three
inches through the shell of the body, turn in boxes arranged under the
seats, and run on a small track laid through the tube. One end of the car
is provided with a disk or head which fits the tube and forms a traveling
piston. There is a door in the disk, also ventilating valves; the lights and
waler-gauges are also arranged upon the disk. The disk presents a superficiat area of twenty-eight feet, against which the atmospheric pressure acts
to propel the car.
The JEolor or blowing-wheel is made in the form of a screw propeller.
It is ten feet in diameter, made of Wood, has eight blades, and revolves
at the mouth of the tube opposite to that at which the car enters. When
the screw turns in one direction it sucks the air through the tube and the
car is drawn in. The car as it passes along moves a lever which gives a
signal, and by the time the car arrives near the screw the latter is reversed,
which forces a blast of air into tle tube and drives the car back. The 2Eolor
is capable of producing a far greater pressure than can be safely used upon
the car in so short a length of tube.
There are two of the Eolors at the Exhibition. One of them works
the Pneumatic Railway, the other, of smaller size, the Postal Pneumatic
Dispatch. Both are driven by one of Root's little trunk-engines, diminutive in size but exceedingly compact, runs beautifully, and gives out abundant power.
The visitors at the Exhibition manifest a lively interest in the Pneumatic Railway, and all seek for the ride. To be carried along by the air pressure is an entirely new sensation. More than twenty-five thousand persons
have already been safely carried, much to their enjoyment and satisfaction.
Mr. John D. Gilbert is the conductor and accompanies evsey train. It is
probable that a pneumatic railway of considerable length for regular traffic
will soon be laid down near New-York, under the auspices of the Pneunatic Dispatch Company of New-Jersey, of which Mr. Beach has lately been
elected President. Great credit is due to the Holske Machine Company,
who were the builders of the Pneumatic Railway and the Pneumatic Postal Dispatch as presented at the Exhibition. The whole work, tubes, cars,




42                   THE PNEUMATIC DISPATCH.
blowing screws and all, were constructed by them in the short space of six
weeks. Considering that every thing was of a novel and experimental
character, this was making good time. The work was conducted under
the immediate personal superintendence of Mr. W. F. Holske, who is one
of our most reliable, experienced, and energetic mechanical constructors.
[From the " New-York Tribune," Sept. 27, 1867.]
THE PNEUMATIC PASSENGER RAILWAY AND POSTAL DISPATCH AT THE AMERICAN INSTITUTE.
THE Exhibition of the American Institute has at this time almost
reached its culminating point. Nearly all the departments are perfect, and
the efforts of the Board of Managers are beginning to show their fruits in
the splendid display which is now offered to the public. Upward of 100,000
visitors must have attended the fair up to the present time, and the interest
manifested in its many interesting and instructive features are on the increase daily. One of the principal features of the Exhibition-and, indeed,
one which has occasioned a vast amount of interest-is the Pneumatic Railway, a model of which has for some time been in the course of erection and
completion on the east side of the building; and the importance of this
invention, together with the well-founded professions of its projectors and
promoters in this country, demand a brief historical and descriptive sketch.
The first attempt to use atmospheric pressure, as a locomotive power, was
made in 1810, by Herr Medhurst, a Danish engineer, who, it is said, then
projected a theory for carrying mail-matter through a pipe, and thus distributing it over a large city, or through a populous province. In 1824 an
Englishman, named Vallance, exhibited plans for a Pneumatic Dispatch,
and also for a railway carrying passengers on the same principle; but it
was not till the year 1832 that plans were so matured that the public were
interested in their favor. The pneumatic principle was thoroughly canvassed in England from that time until 1838, when patents were granted to
Messrs. Clegg & Samuda, upon models which were considered practicable
by some capitalists.
The first railway constructed on this principle was an experiment, two
miles in length, from Dalkey to Kingstown, in Ireland, near Dublin. Another, near Croydon, England, over six miles in length, followed; and this
was succeeded in 1845 by one in France, between St. Germain and Nautienes, near Paris, a distance of two miles. The main difficulties in these
experiments were those attending nearly all embryo schemes of this sortheavy expenses in working-and they were conducted with varying success.
The longest lived of these experiments was that in Ireland, which passed
away five or six years ago, being supplanted by a better understood locomotion by steam. The principle in use in this experiment was very different
from the one at present in vogue, where the cars pass through the tube. In
the former case the tube lav between the rails and below the cars, which
were connected with the interior of the tube by iron rods passing from the
bottom of the cars through an open slit to the tube below. This slit was
closed as fast as the rod cut its way through, by self-closing flanges, which
were brought down more firmly as the vacuum was produced inside the
tube. The tube was closed at each end, where the engines and air-pumps
were situated, by valves of peculiar construction, which allowed the sliding
rod to pass in and out freely and smoothly, without letting in the air. (See
Fig. 3.) But it was found that the air could not be kept sufficiently confined
within the tube by this method, and the experiment was gradually abandoned.




THE PNEUMATIC DISPATCH.                    43
But enough had been demonstrated by the above-mentioned attempts
to prove that the principle of pneumatic locomotion was feasible, and the
matter obtained the study of both inventors and capitalists.  England
has been foremost in demonstrating the practicability of the pneumatic
principle to the world at large. In 1861 the Pneumatic Dispatch Company
was formed in London. The first experiment was made in Battersea Fields,
on the south side of the Thames, in the south-west suburbs. An iron tube,
a quarter of a mile long and made of iron, was laid along the river bank,
and mail-bags, parcels, and even workmen, were carried through at a great
rate of speed.
In 1864 a tube of similar construction, 600 yards long, for the carriage
of passengers, was built in the grounds of the Crystal Palace at Sydenham,
and thousands of passengers were carried through this in a long, roomy car,
by a current of air generated by an immense fan, and again drawn back by
a vacuum created by the same instrument. (See Fig. 4.) This journey of
600 yards was performed, either way, in fifty seconds, with an atmospheric
pressure of only two and a half ounces to the square inch. These successful experiments have been productive of fruitful results. The extensive
pneumatic dispatch line which was opened last year from Euston Square to
Holborn (two miles) has been successful, and has since been extended to
the General Post-Office, another mile eastward.
But the greatest enterprise which has yet been established on this plan
is the Waterloo and Whitehall Pneumatic Railway, which proposes to connect the two sections of the metropolis of the world by a tunnel under the
Thames, on the pneumatic tubular system. The river will be crossed by
four lengths-each 221 feet-of wrought iron tubing, 13 feet in diameter,
covered with brickwork. The length of the tubes, including the shore ends,
will be five eighths of a mile. The first of these lengths will soon be completed, when it will be floated from the workshops of the contractors
(Messrs. Samuda, of the Isle of Dogs) down the Thames to the place of
submersion. If this great enterprise should be fairly accomplished, the
sub-tubing of the Straits of Dover, forming a railway between England and
the Continent, may be considered as a feasible scheme. (See Fig. 5.)
We come to a more intimate interest when we consider the model of the
pneumatic railway now on exhibition at the American Institute Fair.
Charters for the building of such railways have been granted by the Legislatures of Massachusetts, Connecticut, New-Jersey, and Pennsylvania, and
it is understood that two bills will again be presented to the next session
of the Legislature of this State, the matter of underground railways having
already been placed before that body more than once.
The handsome specimen of a pneumatic railway now erected near the
east wall of the American Institute Exhibition is the project of Mr. Alfied
E. Beach, of the ScientZfic American.
The tube of the passenger railway at the Exhibition runs from gallery
to gallery, and is 107 feet in length. It is six feet long, and is constructed
of wood, the shell being composed of fifteen layers of broad hoops, joined
together by cement, the whole being only 14 inches thick, and capable of
great resistance. The carriage for passenger conveyance is open at the top
and sides, the latter rising sufficiently high to protect the passengers' backs
from rubbing against the sides of the tube, the whole having a capacity to
seat ten persons on either side. The door is placed in the centre of the 0shaped end, which forms the valve or piston when the door is closed. The
four wheels of the car rest on rails laid along the bottom of the tube, and
project through the bottom a few inches only. The carriage is just as free
from the bottom as from the sides of the tubes. (See Fig. 7.)
The motive power, which is placed at the northern end of the tube, con



14                  THE PNEUMATIC DISPATCH.
sists of a fan ten feet in diameter, which is, indeed, a screw-propeller, with
eight blades, so constructed that the pitch of the blades is not more than
twelve inches. This fan, driven by an engine almost immediately underneath, can make 200 revolutions per minute. Turning in one direction, it
produces a vacuum by exhausting the air from the tube, and throwing it
off through apertures in the chamber, thus drawing, or rather sucking, the
car at the other end rapidly toward it. Of course, the motion, when reversed, produces the opposite result, the volume of air then taken from the
surrounding atmosphere being poured in a resistless stream against the piston or flange of the car, which immediately rushes back to its starting
place.
Mr. Alfred Beach also exhibits at the Fair a section of a postal dispatch,
through which a truck for the conveyance of mail-matter is drawn or propelled in the same manner explained. The tube itself is square, as are the
trucks which pass through it. In connection with the apparatus is an ingenious automatic arrangement, showing how mail-matter, received at different postal depots along the route, may be kept separate and so delivered,
and, in like manner, a correct delivery effected at each station of outgoing
mails. The lamp-post, containing the letter-box above, rises from the middle of the tube, and every time the subterranean truck passes underneath
the contents of the letter-box are made to drop into it, while, in passing in
another direction, the contents of another box, designed for a different destination, are collected in the same manner. Thus the car, when passing
up-town, collects letters destined for that direction, (having been dropped
into the lamp-post receiver above,) and on its down-town trip also collects
all the matter gathered in the other box.  (See Fig. 8.)
The institutors of several gigantic projects will probably await with
interest and anxiety the public verdict in respect to the operations of their
models now in progress at the Exhibition of the American Institute. These
projected enterprises not only include the establishment of passenger traffic
and thle transportation of mail-matter throughout the American metropolis
-and, indeed, over the whole country-but the more colossal one of subtubing the North and East rivers, and thus forming a connection (unexampled for both speed and comfort) between Jersey City, Brooklyn, and
New-York.
The actual expense of laying down pneumatic tubes under the streets of
the city, it is estimated, would not exceed $500,000 per mile, including the
engines and running stock-much less than the putting down of a subterranean steam-car road. The suspension of the model tube at the Exhibition
also demonstrates the practicability of an elevated road, and suggests that
the tube might be readily laid on posts, or brackets projecting from the
houses, or even passing over the house-tops.
Two hundred dollars per foot is the estimated cost of a pneumatic tube
under the East River, which, estimating the distance at 3000 feet, would
require an outlay of $600,000. The projected suspension bridge over the
same stream is to cost $7,000,000, afforling a startling contrast in price. It
is further estimated that passengers, by a through city tube, could be carried from the City Hall to Madison Square in five minutes, to Central Park
in eight minutes, to Harlem and Manhattanville in fourteen minutes, to
Washington Heights in twenty minutes, and by sub-river to Jersey City or
Hoboken in five minutes, and to the City Hall, Brooklyn, in two minutes,
and at a price much less than that at present charged.
The projected Pneumatic Postal Dispatch proposes a wide range of labor.
It is proposed to carry a pneumatic tube of about two or three feet in diameter from the Post-Office up Broadway to Forty-second street, with
branches at Twenty-seventh street, to the Harlem and New-Haven railroads,




THE PNEUMATIC DISPATCH.                   45
and a branch at Thirtieth street to the Hudson River Railroad. A tube is
also to girdle the city, passing through South and Washington streets, so
as to touch all the ferries and such landings where mails arrive and depart,
bringing these points into immediate communication with the General PostOffice. Tubes are also to extend through Chatham street, Bowery, and
Third avenue; also along Broad, Pearl, Canal, Grand, Bleecker, and Fourteenth streets, and wherever the public requirements may need them-all
the sub-post-offices of course being connected with the General Post-Office.
Further, it is proposed to extend the postal tube under the East River, or
over the suspension bridge, if constructed, to Brooklyn, and through the
principal streets of that city, also under the North River to Jersey City,
where it will connect with the Pneumatic Dispatch Company of New-Jersey, to whom, as before stated, a charter has already been granted. By this
company it is proposed to extend their line as soon as possible to the nearest important cities, probably Newark and Elizabeth. By means of such a
network, no doubt, the mails of the suburbs and suburban cities would be
delivered at headquarters with great rapidity. The postal car, it is stated,
could be run at the rate of thirty miles per hour, including all delays at
intermediate stations. Thus, letters might be sent up-town, as high as
Forty-second street and replies received almost with the speed of telegraphic messages.
VARIOUS FACTS IN REGARD TO THE PNEUMATIC PASSENGER RAILWAYMETHOD OF STOPPING AND STARTING THE TRAINS AT THE PASSENGER
STATIONS-PLANS FOR AN ELEVATED PNEUMATIC RAILWAY-HEATING
AND VENTILATION.
STOPPING AT WAY STATIONS.
IN the construction of a pneumatic passenger railway it is a matter of
prime importance, having in view the utmost economy of construction, to
make the tube as small as may be consistent with the safe, comfortable,
and rapid transport of passengers. The inquiry naturally arises, If the car
closely fits the tube, how are the trains to be stopped at the way stations?
FIG. 9. —ETIIOD OF STOPPING- PNEUMATIC CARS AT WAY STATIONS.
The method of stoppage, which is very simple, will be readily understood by a glance at Figure 9. A represents the platform of the station,
BB the pneumatic tube, B' an enlargement of the tube, C the pneumatic




46                   THE PNEUMATIC DISPATCH.
passenger-car, standing at the platform, TT the track. The course of the
air-current by which the car is driven is indicated by the arrows. In consequence of the enlargement of the tube at and near the station, the onward passage of the air is permitted around one side of the car, while the
latter is brought to a halt at the station by means of brakes. To start the
car, it is only necessary to release the brakes when the pressure of the air
against the rear of the car will carry it slowly forward into the neck of the
tube at XX, where the car will then receive the full force of the air-blast,
and speed on its way to the next station with full velocity.
HEATING AND VENTILATION OF PNEUMATIC CARS.
No stoves or fires will be carried upon pneumatic passenger-cars, but
they will be heated by means of hot water foot-cases, similar to those used
upon the French railways. This is one of the safest and most comfortable
methods of car-heating that has yet been introduced.
As respects the ventilation of passenger-cars, the pneumatic system is
the perfection of traveling. The driving-power is a column of moving
fresh air, which is pressing against the sides and rear of the car, seeking
everywhere to find entrance to the interior of the car. An abundance of
ventilators are provided, by which pure fresh air is at all times admitted,
and perfect ventilation secured. No dust or cinders are encountered by
the passenger, and he reaches his journey's end without injury to his apparel from these causes, and without having the complexion smutted with
smoke.
In summer the pneumatic railway will afford a cool and delightful refuge from burning heats, and the passenger will enjoy the luxury of reclining at ease, to sleep or read, and, also, of being transported gently, at a
high velocity.
ELEVATED PNEUMATIC RAILWAY.
In Figure 10 we have an illustration of the pneumatic railway upon the
elevated plan, designed by Mr. A. E. Beach.
The engraving shows, at the left, the arrangement of a light wooden
pneumatic tube, upon ornamental columns.
At the right the tube is represented as resting upon brackets attached
to the buildings. Another plan is to run the tubes over the tops of the
houses; and another is to extend them through the existing vaults under
the sidewalks of the principal streets.
These plans possess the merit of cheapness in execution. They could be
put in operation for a less expenditure than the street tunnels, would afford
a most rapid and reliable means of transit for passengers, and would present a less cumbersome appearance than the elevated railway bridge now
erected on the west side of the city.
[From the "Scientific American," January 5, 1867.]
THE PNEUMATIC DISPATCH.
THE growth of the business and population of New-York City is wonderful. Twenty years ago we numbered less than four hundred thousand inhabitants, while to-day we have nearly one million, and if the same ratio
of increase continues for twenty years longer, we shall then count three
million. Already our streets, spacious, compared with many large cities,
are over-crowded; public conveyances impede each other, and can only
travel at slow pace.  The carrying traffic has become so enormous, the




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48                   THE PNEUMATIC DISPATCH.
number of men, horses, and vehicles so great, that they frequently blockade
the streets, move with difficulty, and of necessity their charges are high.
It costs more to carry a barrel of flour one mile within the streets than to
transport it hither from the mills, distant two hundred miles.
The city postal service, excellent in some respects, fails to afford a tithe
of the assistance it is capable of rendering in the transactions of ordinary
business. No person expects promptness in the delivery of city parcels and
letters; as for out-of-town mails, letters fail to go unless they reach the
General Post-Office down-town from one to two hours prior to the departure
of the car or boat.
The need of some method of relieving the streets and affording to the
public more abundant, quicker, and cheaper means of local communication
was never more pressingly felt than at present.
We are glad to observe that a movement is being made which promises
something practical in respect to the faster conveyance of passengers. We
understand that the Senate Committee of the Legislature has decided to
report in favor of a tunnel passenger railroad, to extend from the southern
extremity of the island, under Broadway, with branches under Third and
Eighth avenues, to Harlem River, a distance of eleven miles.
Of almost equal importance to the material prosperity and business convenience of the city, is the introduction of an underground method for the
safe, prompt, and economical conveyance of all kinds of fieight, goods, parcels, and the mails.
To this service the Pneumatic Dispatch system is admirably adapted, and
to some of its practical uses we propose now to direct the attention of our
readers. The system of communication now generally known as the Pneumatic Dispatch consists in the employment of a closed tube, through which
air is driven or exhausted by means of steam-power and blowers of large
dimensions. Cars or trucks, closely corresponding in form to the shape of
the tube, are employed therein to carry freight, and these are sucked or
blown along, from station to station, literally with the speed of the wind.
The Pneumatic Dispatch is now employed in London with complete success.
By it freight, mail-bags, etc., are transported with a velocity of thirty miles
an hour, up hill and down, around the sharpest curves, with great economy.
A velocity of fifty or one hundred miles, or even more, per hour, may be
obtained, if desired, by simply burning more coal and driving the blowing
machinery faster.
The Pneumatic Dispatch system is also well adapted to the propulsion
of passenger-cars, and for city use it is probably more economical and safer
than any other known means. The superior economy of stationary engines
for steady work is well known. Between pneumatic trains there can be no
collisions; the same current drives them all; if one train stops on the track,
no other can approach it; no engineers and firemen are required on the cars;
no gas or smoke is evolved; the tunnel and cars are constantly supplied
with moving fresh air; the cars run with peculiar steadiness, without any
jerkin' at the start or stop. With an atmospheric pressure of only two and
a lhalf olunces to the square inch on the rear end of the car, a velocity of
twenty-five miles an hour is obtained. The use of the pneumatic passenger
cars in London established these facts long ago.
We have selected for illustration, in connection with this subject, the application of the Pneumatic Dispatch to the city postal service, from designs
by Mr. A. E. Beach, of the Scientific Amlerican.
The engraving herewith presented, Fig. 12, is an interior view of a supposed Pneumatic Dispatch station. Passing through the apartment is seen
the main pneumatic tube, g, having side switch-tubes, h, through which the
pneumatic cars enter and leave the station. Each car, on emerging from




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50                   THE PNEUMATIC DISPATCH.
the switch-tube, is carried by its momentum across the floor into a short
tube, h', which serves as an air cushion and gently arrests the car.
The automatic letter-distributing mechanism is seen in front. The pack.
ages and letters destined for different city stations are placed by the attendant in the rotary letter and parcel boxes, A B C, which indicate the stations to which the packages are to be conveyed and delivered. The pneumatic car is divided into compartments corresponding respectively to the
boxes, A B C, and when the car passes through the tube under these boxes,
a pin, b, upon the car, strikes a projection, a, upon the blade of each rotary
box, and causes it to turn upon its axis far enough to compel the contents
of the box to fall into the car beneath. Each car is similarly operated by a
separate pin, b, and thus the contents of the several boxes at the various
stations on the route are successively transferred into their corresponding
car compartments, without any stoppage of the car. When it is desired to
send the cars through the tube without operating the boxes at the stations,
it is only necessary to renove the pins, b.
The delivery of the contents of the car at the appointed stations is accomplished by opening the car bottom, each compartment bottom, f, being
hinged for that purpose. On reaching station A, for example, the rod, e,
which rests upon the car bottom and projects above the top of the car, will
come in contact with an inclined lug, fastened in the roof of the tube, g,
which lug will depress the rod, e, and cause it to open the bottom of compartment A, and the contents thereof will drop out, through an opening in
the bottom of the tube, upon a table, or other receiver, within the station.
A similar transfer takes place at each station from each car compartment
corresponding to that station, without stoppage of the car. By this simple
means, the collection, transportation, and delivery of letters and parcels may
be automatically effected throughout the entire city, with extraordinary
rapidity, safety, and economy.
The delivery of the contents of a car upon the table of a station is illustrated in the accompanying engraving, Fig. 13, where the main pneumatic
tube passes through the basement. In the receiving office above is a series
of slides or tubes, which communicate respectively with a series of rotary
letter-boxes, A B C D E F, mounted upon the main tube below. These
letter-boxes indicate so many stations to which letters are to be sent, and
they are distributed by the attendant into the slides, A B C D E F, down
which they fall into the letter-boxes, where they remain until a car comes
along, which takes them out and carries them to their several destinations,
in the manner before described.
Fig. 14 represents a lamp-post letter-box, and under its base are two
rotary boxes, one for up-town letters, the other for down-town letters. The
pneumatic cars are intended to pass under these lamp-post letter-boxes, to
collect and carry the contents, as already described.
By the use of the Pneumatic Dispatch letters and parcels may be collected, conveyed, and delivered from and between all stations and lampposts below Forty-second street and the Post-Office, Nassau and Liberty
streets, in six minutes-distance three miles. Letters deposited in any pneumatic post or station, in any part of the city, fifteen minutes before the departure of any mail, will be in time for such mail. Messages, letters, and
parcels could be sent to any address, up or down town, and the answer
returned, all within an hour's time, or even less.
Among the first results of the introduction of the Pneumatic Dispatch,
in connection with the postal service, would be an enormous increase in the
number of letters sent. It would soon become the great popular means of
communication, a sort of Hermes, or winged messenger, employed by the
gods, as we read in ancient mythology, but in these modern times transferred to the service of the sovereign people.




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From Designs by A. E. Beach.




54                   THE PNEUMATIC DISPATCH.
FIG. 14.-THE PNEUMATIC DISPATCH  TAKING LETTERS FROM THE LAMP-POST.
[From Designs by A. E. BEACH.]
Independent of the postal service, which of itself would bring in an
immense revenue, and soon repay the cost of construction, the additional
existing business which the Pneumatic Dispatch would command at once
in the city of New-York, by its unapproachable cheapness and facility, is
something remarkable. We have been at some pains to investigate the
daily movement of packages and parcels through our streets, and the result,
we think, will surprise those who are best acquainted with the business.
There are two or three leading express companies which collect and
distribute three or four thousand packages each per day; each employing
from fifty to a hundred horses, and as many men. But these mammoth
establishments take up but a drop of the flood, comparatively. We have
at least a dozen important express lines to the interior, constantly employing in our streets an aggregate of nearly a thousand men and horses, in the
collection and distribution of' not less than fifteen thousand parcels of all
sizes per day. But the city express system is entirely additional to this,
and twice as large. All the out-of-town express matter is collected and
distributed here by the companies without charge to their customers, and
consequently pays no license fee to the city. But the number of licensed
express wagons doing business for hire within the city is over eleven hundred; and their daily parcels must exceed thirty thousand, if each wagon
be allowed only thirty calls per day, which would barely support man and
horse. Again, this does not include the suburban express wagons, which
are licensed in their respective localities, although their business is wholly
to and from this city, and of which some two hundred and forty come over
every day from the city of Brooklyn alone. Jersey City, Hoboken, Hudson City, Weehawken, Newark, Staten Island, Flushing, Astoria, Jamaica,
Flatbush, and many other places, send in their full quota of daily express
wagons; so that five hundred suburban expresses, with their fifteen thousand daily parcels, must be considered a very moderate estimate.




THE PNEUMATIC DISPATCH.                    55
But all this is a sort of excrescence, the growth of a few recent years,
upon the main body of our system of street transportation. The public
cartmen number upward of seven thousand, with two hundred and seventyfive public porters. Of the private carts and wagons belonging to our
wholesale merchants, manufacturers, and large retail houses, we can only
make inadequate conjecture, so as to be within bounds. Of our eight thousand wholesale merchants, at least one thousand have their own carts. The
manufacturers, who, for the most part, can not dispense with private wagons,
can not possibly have less than two thousand of these in motion. Here
are ten thousand vehicles in the wholesale way. Then we have seventeen
thousand retailers and eleven thousand in mechanical trades. Of these,
some three thousand grocers, and two thousand butchers and bakers, must
have, nearly all of them, wagons for the collection of their numerous daily
supplies of goods or materials, as well as for distribution to their customers.
Allow them four thousand wagons, and let the other twelve thousand retailers have one thousand more. Total of public and private business vehicles fifteen thousand, beside expresses. Give them a low average of thirty
parcels per day-many of them carry hundreds-and we have a total movement of four hundred and fifty thousand parcels. To these add fifteen thousand out-of-town express parcels, fifteen thousand suburban, and thirty thousand city, and we have a total of five hundred and ten thousand per day.
Half a million of parcels and packages already passing through our
streets daily by horse-power-to which we might fairly add a hundred thousand more by hand-furnish the existing basis of business strictly legitimate
for the Pneumatic Dispatch, and capable of being transacted by that agency
at a decisive saving in cost. The latter fact will be apparent on a simple
calculation. The cost of a horse in this city, well cared for, is found by
accurate account to be about sixty-five cents per day. The wages of employees are about three dollars, and the earnings of cartmen five or six dollars, at the lowest. Allow the men an average of four dollars, and let the
wear of wagon and harness, with the expenses and wear of the horse, make
up one dollar a day. Too little, every one will say; but here are over
seventeen thousand horses, as many wagons, and as many men, maintained at
a minimum cost of eighty-five thousand dollars per day, which is an average
cost of seventeen cents for every one of the half million parcels they are
supposed to carry. Of course the price paid, directly or indirectly, must be
higher. Any one generally acquainted with such prices in the city will admit
that twenty-five cents would be a medium estimate for the average.
Reduce this price to an average of ten cents, which would be a lucrative
rate for pneumatic transportation, and you have instantly the proper condition for doubling the business, which the quickness, certainty, and facility
of the new method would soon double again.
Again, as to capital: here are seventeen thousand horses, worth, on an
average, three hundred dollars each, and as many wagons and carts, worth
an average of two hundred dollars more; making a total capital of eight
million five hundred thousand dollars invested in this business in the form
of horses and vehicles alone-enough to extend the pneumatic system
through every thoroughfare of the city twice or three times over.
--— 3- -— J -----




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THE PNEUMATIC DISPATCH.                   57
CHAPTER VI.
PROPOSED CONNECTION OF NEW-YORK CITY, BROOKLYN, JERSEY CITY, AND
STATEN ISLAND, BY MEANS OF THE PNEUMATIC RAILWAY AND SUBAQUEOUS TUNNELS-DESCRIPTION OF VARIOUS SUB-AQUEOUS TUNNELS
NOW  CONSTRUCTED AND PROPOSED-BRIDGE VS. TUNNEL-DE SENDRINIER'S TUNNEL —HOLCOMB'S PLAN FOR A RIVER-TUNNEL-DIXON'S
METHOD OF CONSTRUCTING RAILWAY-TUNNELS-THE PNEUMATIC DISPATCH COMPANY OF CONNECTICUT.
[From the " Scientific American," Jan. 11, 1868.]
COMMUNICATION BETWEEN NEW-YORK, BROOKLYN, AND JERSEY CITY.
WE publish, in another column, accounts, furnished by a correspondent,
concerning the construction of sub-aqueous tunnels, with a view of showing the feasibility of establishing this means of communication between
New-York, Brooklyn, and Jersey City. From these accounts, it would
seem to be no very difficult or expensive work to connect these great cities
by a single tunnel, which, although of small dimensions, would have an immense carrying capacity for passengers. Indeed, through the proposed
eight-foot tunnel it is stated that twice as many passengers can be conveyed as are now carried on all the combined Brooklyn ferries, and there
would never be any interruption of travel by snow, ice, fog, or collision.
The proposed tunnel would be about the same in cross section as the Croton aqueduct, which is 531 feet. This great tube is over forty miles long,
and was built in five years' time, at an expense, including right of way,
land, dams, bridges, reservoirs, and other large extraneous expenses, of
about sixty dollars per running foot. The actual expense of constructing
the tunnel proper did not probably exceed twenty dollars per running foot.
We should be glad to receive information upon this point.
The area of the proposed sub-aqueous railroad tunnel, as described by
our correspondent, is sufficient to take in cars of about the same interior
accommodations as ordinary railway cars.
It is well known that the beds of the North and East rivers are of such
a nature as to present no serious obstacle to the laying down of tunnels.
Undoubtedly, the quickest and best way would be to dredge a ditch deep
enough to contain the eight-foot tube, and sink the same below the bed of
the river; the construction and laying being executed on the plans of Trevethick and other distinguished engineers.
Between Brooklyn and New-York the sub aqueous portion of the tunnel needs to be only 2000 feet in length; and an enterprising corporation
might readily put it down and have it in operation in six months' time.
A tunnel could be laid down and put in operation four years in advance
of this bridge, the construction of both being commenced simultaneously.
During these four years the stockholders of the tunnel would probably receive back their capital two or three times over, in the shape of dividends.
The bridge will cost fourteen times more than the tunnel. Consequently, in order to pay the same interest on its cost as the tunnel, the
bridge must yield to its stockholders an income fourteen times greater than
the tunnel.




58                   THE PNEUMATIC DISPATCH.
SUB-AQUEOUS AND OTHER TUNNELS.
EDITOR SCIENTIFIC AMERICAN:
The return of the inclement season, when boats and vehicles are liable
to be impeded by snow and ice, will probably lend interest to the consideration of additional methods of communication, especially between large
cities and their immediate suburbs. The subjoined history of various tunnels and projects has been compiled with a view to call the public attention
anew to the subject.
THE THAMES ARCHWAY COMPANY.
Among the earliest of the projects for sub.aqueous tunnels were those
introduced under the auspices of the Thames Archway Company, of London, in the beginning of the present century. This corporation, having
obtained authority from Parliament, raised subscriptions to the amount of
~200,000, and prepared, in 1809, to construct a tunnel under the Thames
river for carriages and foot-passengers. The charter prohibited them from
obstructing navigation, and the company started with the idea of operating wholly below the bed of the river. The first business was to bore a
preliminary drift through the route of the proposed tunnel, in order to ascertain the exact nature of the soil and the difficulties, if any, that the
builders would probably encounter. Richard Trevethick was the engineer
of this drift. A shaft of nine-inch brickwork was first sunk on the south
bank of the Thames, to a depth of 76 feet below high-water mark, and the
drift was then extended horizontally toward the opposite bank of the
river. The drift was a temporary tunnel, 5 feet high, 3 feet wide at the
bottom, and 2 feet 6 inches at the top. It was lined with a frame of 3-inch
planks.
The drift was successfully prosecuted for a distance of 922 feet, which
was further than the actual width of the river, the real width being 850
feet at high water and 649 feet at low water. The drift was purposely run
out in various directions, diverging from the true line, in order to test the
soil. At the extreme end of the drift, before it had quite reached the opposite bank of the river, the engineer encountered a quicksand, and finally
gave it as his opinion that the construction of the proposed excavated tunnel on that line was impracticable. He, however, suggested other plans
for laying a tunnel which he considered entirely practicable. Other engineers were, however, of opinion that the original plan was practicable,
notwithstanding the quicksand. The directors concluded that, in so novel
and important an undertaking, it was desirable, before adopting any plan,
to endeavor to avail themselves of the best which the engineering talent of
the country could suggest. They accordingly caused advertisements to be
published in the newspapers, offering a premium of ~200 for the best plan
of construction, and a further sum of ~300 when such plan had been successfully completed.
In response to this advertisement no less than fifty-four plans were submitted, and were examined by two able scientific men, entirely disinterested-Dr. Hutton and Mr. William Jessop. Many of the plans had great
merit, but all were, for various reasons, rejected, except six; and of these
the examiners finally selected, as best of all, the joint project of Mr.
Charles Wyatt and Mr. Hawkins.
We propose now to give a brief outline showing the nature of each of
these six projects, which, at that time, (1809,) attracted great attention.
The plans were presented anonymously to the company, and we are therefore unable to present the names of the projectors, except in some instances.




THE PNEUMATIC DISPATCH.                     59
PLAN FOR A BRICK TUNNEL.
The tunnel to be of brick, a complete circle, 13 feet diameter, three
bricks thick, having a carriage-way, 7 feet 9 inches, between the curbs, a
foot-way on one side, lamps the other. As this tunnel would be buoyant,
the projector proposed to cover and ram it six feet below the bed of the
river, with clay. In laying down this tunnel, the projector proposed to
form coffer-dams, of fifty feet length at a time, in the direction of the tunnel, the walls of the dam being formed by driving down piles; the spaces
between the piles to be filled with prisms of wood, and the whole carefully
calked; the bed of the river to be then excavated and a section of the tunnel built. While this was going on, another section of dam to be put
down. The piles to be sawed off even with the river-bed on completion of
each section.
PLAN FOR A CAST IRON TUNNEL.
This plan was by R. Trevethick, the distinguished engineer to whom is
due the credit of the high-pressure steam-engine. This tunnel was to be
12 feet in diameter, composed of cast iron slabs, each 6 feet long, joints to
be calked. The method of laying dow-n was to excavate the bed of the
river from within a set of piles driven down within a movable coffer-dam.
The movable dam or caisson to be 50 feet long, 18 feet wide, 40 feet deep,
made of 12-inch square logs, fastened with trunnions and calked. The
caisson to be provided with two water-tight compartments, to float the
whole machine. A sufficient weight of ballast to be used to sink the
caisson when water is admitted to the compartments. The caisson being
floated to the desired position, plugs in the compartments are withdrawn,
water is admitted, and the caisson sinks, and its bottom rests upon the bed
of the river. Guiding frames are then arranged within the caisson, piles
driven, a ditch or channel for the tunnel excavated, the tunnel-plates put
together, and the excavated earth rammed down upon the tunnel even with
the bed of the river, as fast as completed. When as much of the tunnel is
complete as the length of the caisson permits, the latter is floated and
moved one length ahead, the mouth of the tunnel being first stopped with
clay and piles to prevent ingress of water. The water within the caisson is
to be drawn off by boring an opening down into the existing drift, described
in the first part of our subject. This plan for building a tunnel was highly
commended for its ease of execution, simplicity, and cheapness. Brick, if
preferred, could be used instead of iron.
PLAN FOR A TEMPORARY CAST IRON, AND PERMANENT BRICK, TUNNEL.
The projector of this plan proposed-first, to lay down a tunnel of cast
iron, to be laid in a ditch dredged in the bed of the river, After the iron
tunnel was completed, he proposed to construct a brick tunnel by boring, the
line to be deep enough to insure solid ground, below quicksands, etc. The
iron tunnel he proposed to construct of separate cast plates, provided with
flanges, and secured together with bolts. The laying of the tube was to be
accomplished by means of capacious iron diving-bells, fitted with the means
for convenient access of men and materials, air-pipes, etc., operated by
steam-engines. It will be seen that the American patents granted for cast
iron tunnels screwed together were anticipated in England more than fifty
years ago.
GROOVED STONE TUNNEL.
This plan provided for the laying of a stone tunnel thirty feet in diameter, the edges of the stones to be tongued and grooved, and joined with
water-proof cement. The stones to be carefully prepared before being




60                   THE PNEUMATIC DISPATCH.
brought to the river. Movable coffer-dams were to be employed, within
which a ditch was to be excavated and the tunnel constructed. The bottom edges of the dams were to be provided with a flexible curtain of tarpaulin, to prevent bottom leakage. The tunnel was to be two feet below
the bed of the river, covered with clay, well rammed. This plan is somewhat similar to Trevethick's, before described.
A TUNNEL OF BRICK OR OTHER MATERIAL.
This plan provides for a tunnel to be laid like the foregoing in a ditch
to be opened by means of a coffer-dam. The tube to be covered with earth
after construction, and rammed, so that the bed of the river directly over
the tunnel will not be elevated. The chief peculiarity was in the construction of the dam, which was to be ninety feet in diameter, made up of stave
logs a foot square, the bottom ends of the logs to rest on the bed of the
river. Stability was to be given to the staves by means of internal hoops.
After one section of the tunnel had been completed, the dam was to be taken
apart, moved along, and erected for the building of a new section.
PLAN FOR A WOODEN TUNNEL.
Apparently the cheapest of any of the plans, and perhaps the most easily
executed, was another of Trevethick's designs for a wooden tunnel, sixteen
feet in diameter. The drift previously constructed by him was to be used
for drainage of the wooden tunnel.
" The cut across the Thames is to. be made beneath the water by a steam
ballast-raising engine twenty-four feet deep below the bottom of the river,
and wide enough to receive the wooden tunnel, and with its sides sloped in
an angle of about 45~. This cut is to be nearly horizontal at the middle of
the river, but declining about six inches toward the south, for delivering the
water from the road down into the drift; the remaining parts at each side
are to be inclined one foot in fourteen, which is about the degree of inclination of the bottom of Holborn Hill.
"This slope will ascend to the surface at the south side about 100 feet
south of the shaft, and at the north side about 150 feet north of Queen
street, in the field adjoining to the Commercial Road; making the total
length of the tunnel about 2010 feet.
"All the earth that is above low water mark may be removed with
spades.
" The wooden tunnel, for which this cut is to be prepared, is to be made
of elm, in lengths of from 180 to 200 feet of six-inch plank, placed two in
thickness, or in two layers, laid so that the joints shall be covered by the
planks in the other layer, fastened together with trennels, hooped outside
with iron, calked, pitched, and made water-tight like a ship. The hooping
to be put on in a spiral form, with the spirals two feet asunder.
"The ends of each length of the tunnel are to be made to fit into each
other, or to be put together with cast iron ferrules, of six feet long, similar
to the joints of a flute.
"Each of these wooden cylinders will weigh about 200 tons, and may be
moved in water nearly as easily as a loaded barge. As many of these cylinders are to be prepared as will extend from side to side of the river, above
low water mark, when joined end to end, which will be about 1340 feet.
From each end of the wooden tunnel to the entrances, the passage is to be
left at intervals open to the surface, to admit light, and is to have both its
sides and bottom constructed of brickwork eighteen inches thick. This
part will extend about 670 feet, (at each side,) and will complete the tunnel




THE PNEUMATIC DISPATCH.                          61
from the surface at one side of the river to that at the other. Staircases for
descending into the tunnel are to be formed at each side; the interval of
the tunnel between these, which will be about 876 feet, must be lighted
by lamps always; the remaining 464 feet (at each side) will receive daylight
through apertures made like wells from the surface, at intervals of about
thirty feet from each other.
"After the cut is excavated, piles are to be driven at its eastern side, about
sixty or seventy feet asunder, to guide the wooden tunnel into its place.
Then the wooden cylinders, (which are intended to be made near the Surrey
Docks,) being ready, are to be rolled into the docks from the banks, and to
be towed to the cut, a little before low water, when there is little or no
tide, being previously loaded with rubbish sufficient to sink them, but kept
buoyant by empty casks attached to them. Here they are to be placed
across the river, resting against the piles above mentioned, their ends to be
joined into each other and to be drawn tight together by a rope and chain,
put through them from end to end.
" At extreme low water the lashings or cords are to be slipped from the
casks, and the cylinders are to be let to sink altogether to the bottom of the
cut, which is to be then filled up with strong clay, well rammed down even
with the bottom of the river. A hole is then to be bored into the bottom
of the tunnel from the roof of the drift, (which is to be previously dug beneath
the cut,) to let the water down from the tunnel to the well of the steam
engines.
"When the tunnel is drained, it will have a great tendency to float, but,
having an average of eight feet of clay above its top, with the weight of
the road inside, its buoyancy will be overbalanced. If, after a number of
years, the wooden cylinders decay, they may be easily replaced by putting
cast iron cylinders, one inch and a quarter thick, inside; and if any-difficulty
is found in letting down the whole of the cylinders at one time, they may be
put down separately, and afterward be joined together beneath the water.
ESTIMATE OF COST FOR 1340 FEET, AND THE LAYING THEREOF UNDER THE RIVER.
Cutting from low water mark to the first light well at both sides, 690 feet long,
80 feet wide at top, and 36 deep, about 45,000 tons, at 2s.................. ~4,500
Cutting from said light wells to each entrance, 640 feet long, about 30 feet wide,
and 12 deep, estimated at 6500 tons, at Is. 6d............................  487
Wooden tunnel, 1340 feet long, 16 feet diameter from out to out, 1 foot thick,
estimated 94,470 feet, of rough elm, or 2362 loads, at ~7 per load......... 16,534
Making, calking, and paving the tunnel, at ~2 per load....................... 4,724
Hoop iron for ditto, half-inch thick, and 3 inches wide, 150 tons, at ~30......... 4,500
Covering the tunnel with 60,000 tons of clay, at Is. per ton................... 3,000
Piles and sundry other timber for the works..................................  500
Bringing and fixing the wooden tunnel in its place, with ropes, anchors, boats,
etc...................................................................  500
Keeping the engine at work one year, attendance, agency, etc., at ~50 per week, 2,600
Incidental charges, 10 per cent on the whole amount.......................... 5,400
Total............................................................. ~42,745"
PLAN FOR A COMBINED WOOD, CEIMENT, AND CAST IRON TUNNEL.
This projector presented plans for f, ur different sizes of tunnels, with
variations of the form in each, from which the company was to choose. One
plan was for a tunnel having a mean diameter of about 11 feet. The sides
were to be on a curve of 12 feet diameter, the bottom on a curve of 10 feet,
and the top 7 feet diameter. Another was to be 16 feet in diameter, and
another 9 feet, both having varying curves. Lastly, a plain tube of 9 feet




62                   THE PNEUMATIC DISPATCH.
diameter was shown. The material and method of construction were the
same for all.
The body of each tunnel was to be composed of segmental plates of cast
iron, with projecting flanges at their four edges, turned outward, by which
flanges the plates were to be fastened together with nuts and screws.
Outside the cast iron tunnel thus formed, a body of cement or hardrammed clay, five or six inches thick, was to be laid, and the whole was to
be inclosed in a casing of wooden planks.
The method of laying was to excavate under the bed of the river. For
this purpose, where there were quicksands, a shield was proposed, having
a face of upright bars, forming a grating, with separations of an inch and a
half. It was supposed that the sand in front of the shield could be picked
down into the tunnel through the bars, without danger to the workmen
from too sudden an influx.
PLAN FOR A WROUGHT IRON TUNNEL, STRENGTHENED WITH CAST IRON
RIBS.
This project was for a tunnel 27 feet in diameter. The cast iron ribs
were to be one foot apart, three inches broad, and four and a half inches
thick, scarfed at each end, the scarfs two feet long and overlapping each
other, fastened with seven bolts passing through the scarfs and through
the wrought iron tunnel-plates. Each rib was to be composed of sixteen
pieces.
The wrought iron plates were to be rebated at the edges, two and a
half feet long, the joints of one row to be opposite the middle of the plates
next adjoining.
PLANS FOR DOUBLE TUNNELS IN BRICK, ALSO IN CAST IRON.
These were projected by W. Murdoch, of Paisley. One plan was for a
double tunnel in brick-that is to say, tunnels, one upon the other, of elliptical form, 27 inches thick. Another plan was for a two-story tunnel made
of flanched plates of cast iron, secured together with bolts, the joints of the
plates calked with lead. The division consisted of an iron floor, secured to
the sides, which were straight, the bottom flat, and the roof arched.
Another form for the division or floor consisted in having shelves cast on
the sides of the iron plates, which supported a floor in. the form of a brick
arch.
Another plan was for two brick tunnels, side by side, the roof supported centrally on arches. In a similar cast iron tunnel the roof was to
be centrally supported on pillars. Another plan was to make a single tunnel for the greater part of the distance, with short double tunnels at intervals of 200 or 300 yards, for the passage of teams
PLAN FOR A SMALL BRICK TUNNEL, AND PECULIAR METHOD OF LAYING IT
IN THE RIVER.
We come now to a novel plan for laying down a brick tunnel, which
was proposed by Charles Wyatt and John Isaac Hawkins. This plan attracted great attention, and seems to have been at one time the favorite
choice of the Thames Archway Company. Some of the parties interested
in the company went so far as to lay down an actual section of this tunnel
in the Thames river, for the purpose of publicly demonstrating the practicability and cheapness of the plan. It is a tunnel of about the same size as
this that it is now proposed to be laid under the river between New-York




THE PNEUMATIC DISPATCH.                       63
and Brooklyn. We shall first describe the method, and then give some
account of the laying of the experimental section:
Width of the Thames river at high water.........................  847 feet.
Ditto  at  low   water..............................................  649  feet.
Greatest depth  at high water.....................................  38  feet 7  inches.
Ditto at low  water.............................................  16  feet 9  inches.
It is proposed to make a brick tunnel, of a cylindrical form, ten feet nine
inches in diameter outside, and eight feet six inches inside, leaving thirteen
and a half inches, or one brick and a half, for the thickness of the wall.
The tunnel to be built in lengths of fifty feet each, and floated over the required situation, where they are to be sunk into a trench prepared for their
reception, and afterward covered over with earth even with the bottom of
the river.
The particulars of the operation are detailed as follows:
1. In a dock communicating at pleasure with the river, build a cylinder
with bricks laid in Roman cement, fifty feet in length.
2. Let the ends of the cylinder be formed into steps and other projections, to keep it even with the other cylinders to which it is to be joined.
3. Close the opening at each end with a hemispherical wall, and in the
upper part of the cylinder, about six or seven feet from one end, fix a cast
iron tube, of six inches bore, having a conical plug ground into it. To the
lower end of this tube screw or bolt another tube, eight feet three inches
long, and on the upper end screw or bolt a pump, of rather larger diameter,
reaching at least forty-six feet perpendicularly above the cylinder.
4. At six or seven feet from the other end of the cylinder, insert a piece of
iron, into which screw a mast, standing parallel with, and reaching the same
height as the pump, being also of the same diameter. Both these must be
supported by braces, screwed into pieces of iron fixed in the brickwork.
The axes of the pump, mast, and cylinder must be all in the same vertical
plane.
5. At the distance of twelve and a half feet from the ends, let into the
upper part of the brickwork two iron hooks, strong enough to suspend, in
water, the cylinder with its appendages. These hooks may be supported
by iron hoops inclosing the cylinder.
6. Fix a cock in one end of the cylinder, near the bottom, having a lever
worked by a connecting-rod forty feet long.
7. A man-hole, secured by a strong iron plate, should be left at the top
of the cylinder, in case it may be found necessary to examine the inside.
8. Put inside the cylinder, for ballast, paving stones enough to form a
pavement five and a half feet wide, and a sufficient quantity of pig or other
iron, to make it float with the masts upright.
9. Admit water into the dock to float the cylinder; shift the ballast till
it floats upright; secure the man-hole, and force the cylinder under water,
where it should be kept for some time. When the work proves to be watertight, take down the pump and masts, with their braces, observing to mark
them so that they may be put up again in the same situations.
10. While the cylinder is under preparation, dig, in the deepest part of
the river, and in the line where the tunnel is to be laid, a trench deep enough
for the cylinder to lie in, with its upper part about six feet below the bed
of the river.
11. Form a scaffold for letting down the cylinders, provide six bases of
cast iron, having spikes at the under sides, somewhat like a harrow, to keep
them from sliding along the bed of the river; each base having three sockets, to receive as many balls, armed with ferrules, into which common scaffold poles are fixed.




64                   THE PNEUMATIC DISPATCH.
12. Lash together the three poles so that they stand perpendicular to the
plane of the base.
13. Fix, by means of the poles, three of the bases in a line on each side,
near the edge of the trench, sixteen feet apart.
14. Lay, across a barge, a platform, containing two windlasses, of the
double-barreled kind, twenty-five feet asunder, each ten feet long; the larger
diameter two feet, and the smaller twenty inches; moor the barge over the
trench, untie the three poles belonging to each base, and tie them to those
of the adjoining bases and to the platform, so that they form supports and
braces for it.
15. To counteract the specific levity of the scaffold, load the bases with
pigs of iron, let down by ropes, the ends of which may be made fast to the
scaffold.
16. Put a rope of at least two inches diameter on each windlass, to suspend the cylinder by, and a pulley on each rope.
17. A steel spring should be laid under each axis of the windlasses, to
indicate, by the degree of flexure, what force is at any time exerted on the
ropes, by which means it will be easy to guard against overstraining them.
18. The cylinder may be guided in any lateral direction, by small ropes
fastened to the scaffold, and acting on the suspending ropes at a distance
below the windlasses.
19. Thus much being prepared, tow the cylinder over its destined situation, within the scaffolding; attach the pulleys of the windlasses to the
suspending hooks, and erect the pump and mast in their places; turn the
cock so as to let in as much water as will give to the whole a small degree
of specific gravity more than water; ease it down gradually by the windlasses, until it arrives at its proper place, which will be known by the tops
of the pump and masts being in a line with fixed points on the shore.
20. Throw in earth to surround the cylinder, and when it is properly
bedded, let in water equal to the weight of the pump, masts, and braces; and
after drawing the pump buckets, and forcing the conical plug into its pjace,
the whole of these may be taken away, after which the cylinder may be
covered with earth taken from the next excavation, even with the bottom
of the river, except the ends, which must be guarded till the next lengths
are down.
21. Remove the scaffolding to a new situation for putting down the
next length, which will be proceeded with in the same manner as the first.
taking care that the ends of the cylinders be made to fit each other, and
brought into contact; but should this not be perfectly effected, the surrounding earth will form a sufficient barrier to the water, until it can be
stopped from the inside.
LAYING THE SECTIONS.
A brief statement of the progress of an experiment made for the purpose
of ascertaining the practicability of constructing cylinders of brickwork,
and of depositing them, through the water, on a given spot in the bed of
the river Thames, at Rotherhithe, with a view to the formation of a tunnel
for foot passengers under the river, from shore to shore. This experiment
was begun in October, 1810, and finished in June, 1811, by John I. Hawkins, engineer:
Two cylinders, twenty-five feet long, eleven feet three inches external,
and nine feet internal diameter, were built of bricks laid in Roman cement;
the ends of these cylinders were closed with spherical bulkheads of the
same materials; a hole twenty inches in diameter secured by an iron plate
was left in each bulkhead, and in the top of the cylinder; a pipe was fixed




THE PNEUMATIC DISPATCH.                      65
in the top of each cylinder, reaching nearly to the bottom, and a pump,
twenty-five feet long, fitted to the upper end of it; an air-pipe was also
made to screw over a hole left for the purpose; a cock of three inches bore
was placed in one end of each cylinder; masts for sight poles, twenty-two
feet long, and graduated, were erected on the ends of the cylinders, and
braced from the sides.
These cylinders were built in a barge, and launched into the water by
sinking the barge; they floated about two feet out of water.
An excavation was made in the bed of the river, near to low water
mark, by the means commonly used for taking up ballast.
A stage was erected over the excavation, consisting of a platform,
twenty-eight feet by twelve, supported on six upright legs, and kept steady
by twelve very oblique braces, formed of scaffold poles and spars, from five
to nine inches diameter; these poles and spars were pointed, and loaded
with iron to overcome their buoyancy, and sunk into the ground by the
weight of the platform, which was thirty-three feet above the bottom of the
excavation, and always out of the water at high tides; on the platform
were two windlasses of the double-barreled kind.
The stage, which, by reason of its numerous braces, might have borne a
great shock, was nevertheless defended from the shipping by two hexagonal
sets of floating booms, one set within the other, but so detached that the
outer boonis might be torn away by ships running against them without
injuring the inner; each boom consisted of three Quebec spars of about
twelve inches diameter, lashed together, and from thirty-five to forty-five
feet in length; the inner booms were held by tour anchors with single
chains, and two anchors with double chains, the anchors being from about
five hundred to seven hundred weight each; the outer tier of booms was
fastened to the inner by slight ropes.
In case the anchors should yield, the booms were hindered from pressing against the stage by six piles, from ten to fourteen inches in diameter,
and forty-five feet long, pointed and loaded with iron, and forced into the
ground by their own weight, and braced by other smaller oblique piles, from
six to nine inches in diameter.
The hull of an old vessel of one hundred and sixty tons was moored
above the booms, with two anchors ahead and one astern; and a seventyton lighter below, with two anchors.
The object of this mode of defense was to check, by a succession and an
accumulation of resistance, the force of any vessel, before it could reach the
stage, and it proved effectual; for, although the outer works were much and
repeatedly injured by the shipping, the anchors being often dragged and
booms torn away, yet the stage remained nearly four months in the most
dangerous part of the river, without sustaining any damage from the shipping, except the breaking off four or five feet of the small ends of two scaffold poles.
The stage being defended, one of the cylinders was floated under it, the
ropes of the windlasses fastened to two hooks on the top of the brickwork,
the pump fixed upon the pipe communicating with the inside, the air-pipe
screwed on, the masts or indices erected and braced, and at high water it
was sunk by letting water in through the cock, and deposited in the excavation at such a depth that the upper part might be seen at low water,
where it was kept suspended while gravel was thrown down and rammed
under the bottom to support it. The rammers were fifty feet long, and a
little heavier than water.
The stage was then removed twenty-five feet nearer the shore, the legs
and braces singly, by means of an anchor-boat, and the platform with its
windlasses, etc., all together, at high water, upon four large buoys; after




66                   THE PNEUMATIC DISPATCH.
which the second cylinder was suspended from the windlasses in the same
manner as the first. At high water the cylinder was let down to its proper
depth, and moved laterally by means of ropes, until the ends of both cylinders were in contact, and their axes in the same vertical plane. A half hoop
of iron which projected over the end of this cylinder rested on the top of the
one before laid down, but the inshore or south end was higher by three
inches than was intended.
These facts were ascertained by the tops of the four masts on the ends
of the cylinders, which were at that time three feet out of water. ~
In this situation gravel was thrown down and rammed under the middle
and north end of the cylinder; two strong poles, pointed and shod with
iron, were driven down by the east side of the cylinder, and their tops secured to the platform, to prevent the cylinders being removed by the
strength of the ensuing ebb tide, before a sufficient bank of earth could be
thrown down to keep it stationary.
The excavation had been made deep enough, but the inshore end of the
cylinder, grounding on the bank at low water the day before the operation
of adjusting took place, brought so much earth down to the bottom as to
prevent that end of the cylinder being lowered again as deep as it should
have been by three inches; this earth might have been removed again in
two or three tides, as it had been before, but under the apprehension of
being ordered by the Port Committee to take the works out of the river, I
determined to conclude the experiment without regard to that three inches,
since the only inconvenience was a space of one inch and a half between
the ends of the cylinders at the lower side, although they were in contact
at the upper; and no doubt was entertained of keeping the water from
passing through this space in any quantity that should hinder the calking
of the joint from the inside.
At the succeeding low water, the cylinders were found to be exactly in
the situation indicated by the masts at high water, after which the joint
was covered with a mixture of mud and gravel; but, owing to the want of
a sufficient bank of earth at the sides, it lay but a few inches thick on the
top, and this, sliding off at low water, wanted that compactness which was
necessary completely to stanch the joint. The influx of water, however,
through the joint was scarcely eleven gallons a minute, when the water in
the river stood three feet higher than that within the cylinders.
These were the principal features of the experiment. The only thing
met with worthy the name of difficulty was the defending of the stage
against shipping.
In proceeding with a tunnel, I would propose to adopt the modes pursued in the experiment, with scarcely any other exception than the defense, which must be more efficient and less extended, and one that can be
removed and pitched again at the same time with, and while surrounding
the stage.
THE THAMES TUNNEL.
England is full of tunnels, and some are of wonderful length. Before
the introduction of railways, when canal transportation was all the rage,
the construction of tunnels through hills and mountains was very common.
Among the most remarkable of these canal-tunnels were those at Worsley,
on the Bridgewater Canal, which were eighteen miles in length.
The most difficult and expensive tunnel ever constructed, considering
its length and size, was the Thames tunnel. The time occupied in its completion was eleven years, and its cost was ~454,714, or about $2,273,570.
The total length of the tunnel, from shaft to shaft, is 1200 feet.  The immense difficulties experienced, and the great outlays involved in the con



THE PNEUMATIC DISPATCH.                     67
struction, were not due to the hard nature of the soil through which the
tunnel was laid. We have already described the previous construction of
the drift-way or small tunnel, which was readily carried through nearly the
same route, at a small cost. We have also described several different
plans which would have been much cheaper, quicker, and better. The
Thames Tunnel Company deliberately selected, at the outset, the most ponderous, massive, costly, and difficult scheme'of construction that could possibly have been chosen, and then adhered to their choice with a dogged
pertinacity characteristic of John Bull. The company might have abandoned their plan for a simpler one at almost any stage of the work, and
could have saved money by the change; but they stuck to it heroically
until their treasury was exhausted. They then applied to government,
and obtained aid to insure the completion, or, rather, almost the completion; for the tunnel is still unfinished. Only one of its two divisions has
been finished inside, and the spiral roadways for teams, in the shafts, have
never been erected. Only foot-passengers can pass through, and from these
a small revenue is derived, little more than sufficient to pay the expenses
of attendants, cleaning, and repairs. But this wonderful structure, solid
and magnificent as it is, will not always remain an idle curiosity. All that
is wanting to render it useful is the construction of proper and convenient
approaches. The progress of metropolitan population and enterprise is so
rapid, that every possible avenue of communication will soon be overloaded, and the Thames tunnel will probably become a great and important railway thoroughfare.
Mark Isambard Brunel was the projector and engineer of the present
Thames tunnel. He was the inventor and patentee of a novel shield, intended to cover the head of the tunnel and protect the workmen while
they excavated the earth under the bed of the river. The construction of
the shield was such that, as fast as the excavation was made, the shield
could be pushed forward and the masonry of the tunnel built up in the
rear of the shield. The directors of the company appear to have been
greatly struck with the merits and novelty of Brunel's shield. It was an
immense machine. Its face was 38 feet wide and 22 feet 6 inches high. It
was larger and heavier than many of our country dwelling-houses; and the
plan was to excavate an aperture under the river-bed large enough to receive the structure and then move it through as the excavation progressed.
It almost passes belief that such a huge, unwieldy machine could be
pushed through the bowels of the earth, underneath a river, its waters
pressing down with a force of 2500 pounds to the square foot. But the
feat was actually accomplished, though at snail pace, the annual average
movement being only one hundred feet a year.
Mr. Brunel once stated before the Royal Academy of Sciences at Rouen
that the idea of his shield suggested itself to him upon an examination of
the insect called the teredo, well known for its ability to bore through the
largest timbers under water. Its head is protected from the water by a
species of shield.
Dr. Tomlinson gives some interesting particulars concerning the building of the Thames tunnel. A vertical shaft of masonry, over 3 feet thick
and 50 feet in diameter, was first sunk in the river-bed, to a depth of 80
feet. This was a most laborious and expensive work. A similar shaft was
subsequently sunk on the opposite side of the river, with which the tunnel
connects. During the progress of the tunnel the river burst through between the brickwork and the shield several times, and a number of lives
was lost.
The excavation for the tunnel was thirty-eight feet wide, and twentytwo feet six inches high; and, in order to leave a sufficient depth of ground




68                   THE PNEUMATIC DISPATCH.
in the middle of the river above the brickwork, the tunnel was formed with
a declivity of two feet three inches in one hundred feet. The ground above
was supported while the excavation was going on by a shield, consisting of
twelve massive iron frames, placed side by side, and capable of being slid
forward, independently of each other, for a short distance, by means of
screws abutting against the end of the completed brickwork, which followed closely on the excavation. The shield was supported on flat soles,
capable of being easily moved forward. The top and sides were also
closed in by flat plates, which were supported by massive framing, and
also fitted close to the brickwork, by which means the soft earth was prevented from falling in. Each frame of the shield consisted of three stories,
with a cell in each, in which one man could work; the front of each cell,
protected by a series of narrow poling-boards, each of which was held in
its place by an arrangement which allowed it to be fixed in a vertical line
even with the face of the shield, or a few inches in advance thereof. Each
miner began operations by removing the upper poling-board in his division
of the shield, and excavating the small portion of earth thus exposed to
the depth of about six inches. He then replaced the poling-board, and
caused it to press, by means of jack-screws, against the face of the excavation. He next removed a second board, whereby a fresh portion of earth
was exposed and excavated as before. When all the poling-boards in one
frame of the shield had thus been advanced six inches, the frame itself was
moved forward, and the same series of operations repeated. The frames of
the shield were thus alternately moved forward, slowly and with great
caution, the brickwork following close upon the shield, and inclosing two
arched passages, twenty-six feet four inches in height from the invert to
the crown of the arch, and thirteen feet nine inches span at the springing
of the arch. This shield was so damaged in the course of the work that
it had to be taken down, and a new one raised. The arch, the invert, and
the curved side walls are laid in concentric rings, either a whole brick or a
half brick in thickness, each ring presenting a plain face, no bond being
employed between the successive rings. The tunnel is built with the hardest picked stock bricks. The first or inner ring of the arch is laid in pure
cement, and the other portions of the work in half cement, and half clean,
sharp sand.  The bricks for the semicircular portion of the arch were
moulded to the true wedge form, so that the bricks radiated with parallel
joints between them. The total thickness of the brickwork at the thinnest
points, where the inclosed arches approach nearest to the boundary of the
rectangular mass of brickwork, is three feet. A solid wall, three feet six
inches thick at the top and four feet at the bottom, was constructed between the arches; small transverse arches being afterward cut through it
at intervals to form openings from one tunnel to the other. The whole of
the brickwork is laid in Roman cement, and each archway is to be finished
with a lining of cement, a carriage-road and a narrow footpath adjoining
the central wall. Only one archway, however, has been thus completed.
A brick drain is laid down from the centre or lowest point of the tunnel to
the Rotherhithe shaft, by means of which any water that percolates through
may be removed. The inclination of the roadway conducts the water from
the other half of the tunnel into the drain.
THE SECOND THAMES TUNNEL.
A new, smaller, and cheaper tunnel under the Thames is now in progress of construction by the Waterloo and Whitehall Pneumatic Railway
Company. This tunnel is to be put down substantially on the Wyatt &
Hawkins plan, heretofore described. That is to say, the tubes, after comrn




THE PNEUMATIC DISPATCH.                    69
pletion, are to be floated to the required line, then sunk in a ditch below
the bed of the river. The tubes are built upon ways, and launched like a
vessel. The reader will find an engraving of one of these tubes, taken from
a photographic view as it appeared before launching, on page 165 of this
paper, Vol. XVI., March 16, 1867. The tunnel is to be composed of a series
of 1-inch boiler iron tubes, each 221 feet long, covered and lined with
brickwork. The extremities of the tubes are to be sustained in massive
iron cradles, sunk in the river below its bed, upon foundations of masonry.
The internal diameter is to be 12 feet 9 inches.
THE WEYMOUTH TUNNEL.
This tunnel is 450 feet in length, excavated under the bed of the Backwater, at Weymouth, England. It was commenced by sinking a shaft, 50
feet through gravel and clay, of 14-inch brickwork, laid in hydraulic cement; the tunnel then strikes off horizontally a distance of 450 feet, with
a gentle rise to the other end. The tunnel is 7 feet high, 4} feet wide.
For fifty feet near one end, where the clay is strong and retentive, the
walls are only nine inches thick. The opposite shaft is forty feet deep.
The depth of water over the tunnel is 13 feet at high tide, 7 feet at low
tide. There was but little leakage.
The construction of small tunnels under rivers is a very easy and comparatively cheap work. It is only when we come to gigantic structures of
immense weight, such as the Thames tunnel, that the costs and difficulties
become serious. The Weymouth tunnel was begun in 1834 and completed
in a year.
PROPOSED TUNNELS BETWEEN NEW-YORK, BROOKLYN, AND JERSEY CITY.
An organization has been made for the purpose of procuring legislative
authority for the laying down of tunnels, upon the general plan just described, between the cities of New-York, Brooklyn, and Jersey City. The
proposed tunnel will be cheap in construction, and is to have an interior
diameter of about eight feet. The New-York termini are intended to be
at or near the City Hall Park, the terminus in Brooklyn being at or near
the City Hall, or the junction of Fulton and Court streets, a distance of
just one mile. Trains of passenger-cars will pass through this tunnel, from
end to end, in one minute, and will be propelled by atmospheric pressure.
The cars will be of about the same dimensions as the ordinary street passenger-cars, will be brilliantly lighted, and run with very little noise or
vibration. Experience has shown that air-pressure is preferred as a motor
to locomotive or horse-power, as all jerking is avoided, and the atmospheric
car glides along with a smoothness resembling that of a vessel upon the
water.
The number of passengers now annually carried upon the ferry-boats
between New-York and Brooklyn is 40,000,000, being an average of
110,000 per diem, or 10,000 passengers per hour, reckoning the day at
eleven hours, during which period the great majority are at present
carried.
In the transport of passengers through the proposed Brooklyn tunnel,
trains, capable of carrying 1000 passengers, will be started from each terminus every five minutes. 24,000 passengers will thus be carried every
hour, which is more than double the amount of transportation now required.
The area of the cross section of this tunnel would be about the same as
the Croton tunnel or aqueduct, which is 531 square feet. The Croton




70                     THE PNEUMATIC DISPATCH.
Aqueduct, from the dam to the reservoir, is 401 miles long, built of brick
and stone. The whole cost, including dam, land, right of way, bridges,
reservoir, etc., was $12,500,000. Of this amount, nearly $2,000,000 was
for distributing pipes. The time occupied in construction was only five
years.
THE CHICAGO TUNNEL.
Probably the longest sub-aqueous tunnel in the world is that at Chicago
for supplying that city with pure water. It extends for a distance of two
miles under the waters of Lake Michigan. This tunnel illustrates the
cheapness and rapidity with which tubular structures of small dimensions
may be cut in easy soil. The problem was, to go horizontally through a
strata composed chiefly of clay. The original contract price for the entire
work was $315,000. But, in consequence of the sudden great rise in
prices, the amount proved inadequate. Changes were also ordered in the
construction of the piers and vertical shafts, to give them greater solidity,
and the contractors are understood to have received much more than the
contract price. Perhaps the largest share of the whole cost was involved
in the construction of the two vertical shafts, as the horizontal tunnel was
easily made. The outer shaft is 66 feet deep, 9 feet in diameter, composed
of cast iron, set within a coffer-dam, which is 90 feet in diameter and 45
feet deep. The interior space between the dam and the shaft is to be filled
with solid stone-work, and the pier thus formed is to be surmounted with a
lighthouse. The horizontal tunnel, two miles in length, was constructed in
a little more than one year. It is 5 feet in diameter, composed of 8-inch
brick, laid in the best cement.
TUNNEL UNDER THE CHICAGO RIVER.
The tunnel under the Chicago river, Washington street, is now progressing rapidly and favorably.  The contractors are Lake Clark & Farwell.
There is every prospect that the tunnel will be completed during 1868,
when the people of Chicago will enjoy uninterrupted communication with
the opposite bank. The whole length of the work, from the centre of
Franklin street to the centre of Clinton, is 1605 feet, of which 932 feet is
the length of the tunnel; the remainder consists of the open approaches.
TUNNELING THE TEES.
A late number of Engineering describes a plan, proposed by Mr. Head,
of Middlesboro, England, for tunneling the river Tees, for the purpose of
connecting Middlesboro with Norton Junction by rail. He says:
"I propose that it should be a single wrought iron tube, but divided
into two passages by a water-tight web or bulkhead. This division should
be strong enough to resist the pressure of the water, and preserve, at least,
one side for traffic in case of accident to the other.
" As to the construction of the main tube, I would recommend something on the same principle as that exhibited in the hull of the Great Eastern steamship; that is, an outer and inner shell, for security and strength.
The bottom should be made flat, or slightly arched downward. The whole
section would thus resemble that of a gas-retort or culvert.
"The best plan for placing the tube in position seems to be as follows:
As near as possible to the point of crossing, it should be constructed by the
river side, in a temporary dry-dock formed by earthen embankments, and
at such a level that the tide would float it if admitted by the removal of a
dam. The tube should be erected upon timber balks, placed crosswise at
intervals of 5 feet, and bolted to the structure.




THE PNEUMATIC DISPATCH.                     71
"These would be floated away with it, and afterward serve as sleepers.
" Meantime, the groove in which it was intended to lie would be cut
across the channel of the river by dredgers. It is no new thing to dredgr
to an increased depth of 30 feet. It is, in fact, the cheapest method of excas
vating in all cases where it can be applied. The new Suez Canal has been
greatly indebted to the use of dredging in the formation of its approaches.
Dredgers have even been made to cut their way into the solid shore, the
water following to float them as they made a channel for it.
"In the bottom of the groove so prepared concrete must be tipped from
barges, and spread to a level by the aid of diving-bells.
"V When the tube was completed, it would be necessary to cover over
the ends temporarily to make it water-tight. It would then easily be
floated out of the dock to its permanent position. To let in sufficient
water to sink it would not occupy many minutes more. The interval between the ebb and flow, which, at spring tides, is about an hour, would be
ample to accomplish every thing necessary. Concrete might then be teemed
at the sides and over the top, and, in this way, assisted by the natural tendency to silt up, it would soon become permanently fixed. Embankments
of clay would now be thrown out from the shore on each side of the line
of the approaches, and would join across the end of the tube.  As soon as
they were made water-tight with clay puddle, the water between must be
pumped out and the approaches built in the intervening space."
ROWLAND S PLAN FOR SUB-AQUEOUS TUBE.
Mr. T. T. Rowland, of Green Point, N. Y., is the inventor of a method
of construction which has the merit of strength and solidity. A strong
tube is first made of boiler iron, which is covered and protected by means
of blocks of hydraulic cement, of segmental form, fifteen inches thick.
These blocks are secured by means of screw-bolts to flanges upon the exterior of the tube, the arrangement being such that the bolts and iron-work
are wholly covered by the cement and carefully protected from the corrosive effects of the water. The exterior of a tube thus made would present
a solid surface of hydraulic cement.
[From the "Scientific American," June 15, 1867.]
DE SENDZIMIR S PLAN FOR A RIVER TUNNEL.
As long ago as 1857 we published (vide Scientific American, Vol. XII.,
No. 30) a plan proposed by Mr. Joseph De Sendzimir, of South Oyster
Bay, Long Island, by which a passage across the East river could be secured without a structure exposed to gales, and without approaches entailing travel of three times the width of the strait. It was, in brief, similar to that now in progress across the Thames at London for the Pneumatic
Dispatch. The accompanying diagram (Fig. 16) shows the plan. It was a
submerged tube of iron sunk in the bed of the river, the central portion
level, and the remainder rising gradually to either shore. In order to
diminish the grade, the tube, on the Brooklyn side, where the natural descent is greater than on the other side, makes a curve or bend as seen in
the diagram. The deepest portion of the river bed is only forty-seven feet
below the surface at low water, and the tube may be either supported on
piles driven into the bed of the river, or lie upon a bed scooped for it so
that the top may reach only to the surface of the bed. That this plan is
feasible can not be successfully denied; that it will offer no obstructions to
navigation and the tides, and that it would be removed from danger of disturbance from floating ice and from gales, is susceptible of proof. Its cost,




~~" ~~I7J  i~~~I  III                          ___                                     -1 ~~~~~ la
Pi I7.-H-olcomb': Plan for et -lunnei bebpeen IVrook&yn and X2evp- Toric




THE PNEUMATIC DISPATCH.                    73
NEW YORK.,
-/f       e   v   water
BROOKLYN c
FIG. 16. —DE SENDZIMII'S TUNNEL.
estimated at only about $200 per running foot, is so much less than that of
any bridge, that twelve of these tubes could be laid for the cost of a single
bridge. Its approaches could be close to the shore, and therefore not interfere with the rights of property owners. In every aspect the submerged
tube appears to be better than the aerial bridge.
HIOLCOMBIS TUNNEL.
Subsequently, as seen in No. 39, Vol. XII., 1857, Scientific American, we
published engravings of a similar plan, which we herewith reproduce. It
was suggested by H. P. Holcomb, of Winchester, Ga., and the engravings represent a profile view, and the entrances, style of tube, and a cross section.
In Fig. 17, the tube is shown supported on piles sunk in the bed of the river;
Fig. 18, one of the entrances; Fig. 19, across section; and Fig. 20, the construction of a portion of the tube, which is of wrought iron. Those portions
which are corrugated are intended to rest on foundations of piles, and the
corrugations are intended to strengthen the tube, and also to provide for
any expansion and contraction. Our opinion is, that, if the whole tube was
built of corrugated iron, it would be immensely stronger, and could also be
made of thinner iron, thus reducing the cost.
The plan of building the tubes proposed is similar to that followed in the
construction of the pneumatic tube in London; that is, that it be built in
sections, the ends. of which are made water-tight; and then the sections
floated to place, and sunk by admitting a sufficient quantity of water, to be
afterward pumped out. The joints to be made by bolted flanges.
We see fewer objections to this style of crossing rivers, especially when
very wide, or where a bridge must be elevated, than to any other. If the
tube is sunk in a bed dredged for it, there can be no reason why it might
not last for generations, especially if, like that of the Thames, it is protected externally by courses of brick masonry. We gave an engraving and
description of that tube in No. 11, current volume. No objection to the
submerged tube, except the fact of its situation, would seem to obtain, which
might not be equally valid when urged against the elevated bridge. Certainly teams and street-railway cars could as readily traverse the tube as
the bridge. In either case, there must be an ascent and descent. But, beyond the fact of less cost in favor of the tube, there is the superiority in ease
of approach, and consequent shortening of the distance. The two plans
seem, at least, worthy of comparison by those interested in the subject.




Pig. I/S..Fi]. 20.                                    f9.
JIotcomb'/an for a Tunnel




THE PNEUMATIC DISPATCH.                    75
[From the " Scientific American," October 5, 1867.]
DIXON'S METHOD OF CONSTRUCTING RAILWAY TUNNELS.
THE problem how to relieve the city of its over-crowded population, how
to extend its cramped proportions to the upper end of the island of Manhattan, how to connect it by rapid and low-priced means of communication
with the neighboring shores of Long Island and New-Jersey, and how to
provide comfortable and cheap homes in its vicinity for its myriad sons of
toil, who labor ceaselessly to enrich grasping landlords, and who pass their
hours of rest in dwellings which are a disgrace to a civilized age, is one
which interests every humanitarian, every capitalist, and every lover of the
city's prosperity, almost as deeply as the numerous class which is more immediately benefited by its solution.
Railroads-aerial, pneumatic, and underground-to supersede the tedious horse-cars, and bridges as a substitute for ferry-boats, have been proposed. A commission, consisting of three Senators, the Mayor of the city,
the State Engineer, and the Engineer of the Croton Aqueduct Board, was
appointed to sit during the recess of 1866, and inquire into the best means
of affording the much-needed rapid transportation. They advertised largely,
and received a great number of plans and suggestions embracing every description of railroad. After giving the matter a thorough investigation, they
reported to the Legislature, last January, recommending unanimously the
underground railroad as superior to all other methods for this island. Notwithstanding this report, and the numerous petitions of owners and lessees
of property in favor of the measure, the Legislature refised to grant a
charter to any of the numerous applicants, owing to dissensions among the
parties applying. The only measure of relief (?) granted was the authority
given to construct two bridges across the East river, which can not be
completed in several years. The time, however, will come when public
opinion will demand the adoption of all the methods that can be made
available; and then the plan recently patented by Mr. Joseph Dixon, of NewYork City, and illustrated in the accompanying engravings, will undoubtedly meet with the success its simplicity, economy, and adaptability for the
underground and pneumatic systems deserve.
In applying Mr. Dixon's method to underground railways, the excavation is made as usual, with the exception that a much narrower trench will
be needed to accommodate the iron plates forming the sides in place of'
stone or brickwork. A foundation of stone is then placed, to which the
side plates are bolted, and the plates forming the arch are first placed on
a movable framework and bolted to each other. The framework, being
made so as to be raised or lowered by means of a screw-jack, will be raised
slightly above the sides while the flanges of the arch-plates are being bolted
together, and when ready the fiamework will be lowered till the arch rests
in its place on the sides. A section is now complete, the centre plate acting as the key, and every joint answering as a powerful strengthening rib,
and being tongued and grooved, and packed with cast iron or other cement,
will be perfectly water-tight. The means of ventilation will be through
iron air-shafts, rising in the form of an obelisk or column of open latticework, and surmounted by lamps to be used in place of the present street
lamps.
For constructing the pneumatic railway Mir. Dixon's method will equally
well apply where the tube is of sufficient diameter to contain the carriages,
and in which they are propelled by the direct expansion of the air; the ease
with which the parts are put together, their comparative cheapness in cost,




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THE PNEUMATIC DISPATCH.                     77
the facility with which they may be handled and transported to the place
required, render it incomparably superior to every other method of tubing
hitherto employed.
For a submarine tunnel this method stands preeminent. As before remarked, the bridges about to be constructed across the East river will take
several years to complete, one of them at an estimated cost of eight million
dollars; for this sum several tunnels, each affording as much facility for
traffic as a bridge, could be laid across the East and North rivers, and not
one of them need occupy over a year in constructing.
For vaults under sidewalks, such as are used by the large newspaper
establishments, and by dry-goods stores, breweries, etc., this system can be
advantageously applied, and the size of the vaults largely increased by substituting the iron plates for the thick stonework and brickwork generally
used.
In the construction of tunnels, where the engineer is forced to drift
through a loose soil, the advantages of arches formed of these iron plates,
with the joint inside, are too apparent to require any thing more than a
mere mention.
[From  the "Brooklyn Daily Eagle," January 18, 1868.]
CO3MMUNICATION WTITI NEWl-YORK-IS A PNEUMIATIC RAILROAD FEASIBLE?
CHEAP, rapid, safe, and uninterrupted communication between Brooklyn
and New-York is an essential condition of the future growth and prosperity
of this city. No natural advantages which Brooklyn may possess, no attractions which we may be able to add to our city, will offset the disadvantage
we now labor under in the inadequacy of the means of communication between the two cities, and the injury to which we are subjected by the interruption of this communication at certain seasons of the year.  Brooklyn is
destined to be the home of a large proportion of those earning a living by
hand or brain in New-York City. A large local trade will necessarily follow;
and in the future it may be that Brooklyn will monopolize the trade of the
island lying back of it; but its main reliance will be in the advantage it
may be able to hold out as a place of residence for men doing business in
New-York. No advantage will offset, in the eyes of this class, the probability or possibility of the interruption of communication between the two
cities.  The credit of a merchant may be compromised by an hour's unexpected delay on this side of tie river. The usefulness of a clerk may in a
great part depend on the promptness with which he attends to his duties,
and no employer will be satisfied for any length of time with the excuse that
a residence in Brooklyn involves irregularity at his business. The mechanic
can not afford to lose any part of his day's earnings in waiting until fogs
clear off, or until the turn of the tide opens the way for boats to convey him
to the scene of his daily labor. It is safe to say that there is apparently no
limit to the growth of Brooklyn, save that which may be imposed upon it
by the difficulty of access to New-York City.
If we had had to depend on boats moved by horse-power up to this time,
it is not too much to say that Brooklyn would have remained up to this hour
a village.  Steam ferries met a pressing need, and have answered our purpose for over a quarter of a century. While it would not be correct to say
that they have outlived their usefulness, it is safe to say that we have overtaxed their capacity as a means of communication between the two cities.
Safe, speedy, and, above all, certain communication with New-York is the
condition of our future growth, and no question which can be brought to the
attention of our people so imperatively demands their attention as does tLis.




78                   THE PNEUMATIC DISPATCH.
Newspapers may find fault with the ferry companies, when an accident happens, for neglecting this or that means of guarding against it; but they have
a ready, and, let us add, an adequate answer to these complaints in the necessity which exists for sinking individual safety for the general accommodation. So satisfied are the ferry managers that their resources are inadequate
to meet the future needs of Brooklyn, that, to every project for opening other
means of communication than that the ferries offer, they seem desirous of
giving a cordial cooperation.
The project of bridging the East river was discussed in Brooklyn before the commencement of the present century. Far seeing men saw then
that the first want of the city was uninterrupted communication with NewYork. The appliance of steam to ferry navigation provided for immediate,
and, as was believed even by the most sanguine, for fiture wants; but steam
ferries are now as inadequate, in view of the future, as boats propelled by
horse-power were seen to be forty years ago. The bridge project has therefore been revived. It finds favor from all classes; for it is seen that, whether a safe and uninterrupted means of communication between the two
cities costs seven millions or seventy millions, Brooklyn in time must and
will provide it. The promoters of the bridge project are not mainly interested in the enterprise as a speculation; their main object is to provide for
Brooklyn the essential condition of its future growth, and this clone, their
main purpose will be accomplished. By a bridge seemed to be the most
feasible method of connecting both cities; but fortunately, before we are
necessarily committed to it, a new motive power challenges attention, and
it now seems probable that through it we may secure the end we have in
view, and in doing so provide for the accommodation here of five times our
present population.
In the early part of the present century, a Danish engineer conceived
the idea that if a tube was laid down, a box fitting in it might be propelled
through it by the pressure of the atmosphere at one end, while by exhausting the air at the other, the box, with the same velocity, would rush back
to its starting-point.  This was the inception of what is now known as
the "Pneumatic Dispatch."  No practical results followed from the labors
of the Dane. In 1824, an English inventor exhibited plans for a "Pneumatic Dispatch," for the conveyance of letters and packages, and he was sanguine enough to hope that passengers could be conveyed by the same
means. Successive inventors took up the work of their predecessors, and
in 1861 the scheme was so far perfected that a Pneumatic Dispatch Company was formed in London. An iron tube over a quarter of a mile long was
laid down, and mail-bags and parcels were carried through it at any velocity required. But- if parcels could be carried through, why not passengers? There was no reason why, except that adequate accommodation was
not provided. The workmen froim time to time accepted such accommodation as was offered, and, by reclining in the mail cars, were conveyed as
safely and expeditiously as by a locomotive.  The Pneumatic Dispatch
was conceded to be a success, so far as the conveyance of mail matter,
packages, freight, etc., was concerned.
The principle being conceded to be sound, inventors turned their attention to the extension of its application. In 1864, the tube gave place to a
tunnel, which was constructed on the grounds of the Crystal Palace, Sydenham, London. By a current of air, generated by an immense fan placed at
one end of the tunnel, a car carrying forty passengers was propelled through
it; as the car arrived at its destination a vacuum was created by the same
fan, and the car returned to its starting-point, at any required velocity. We
do not desire to encumber here our statement of the main facts by a description of the machinery by which the air is propelled through the tunnel,




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80                   THE PNEUMATIC DISPATCH.
or " sucked" out of it, to use a homely but expressive word. It is enough
for our present purpose to say that the question of the practicability of this
part of the scheme is not open for discussion. At the late Fair of the American Institute, in New-York City, one hundred and seventy thousand people
practically tested the use of air as a motive power.
Sanguine men believe that the new means of land locomotion will supersede all others now known to us. The steam locomotive, they hold, is about
to yield to its supremacy, and the pneumatic car, protected from the possibility of accident, will run up mountains, along the beds of rivers, and under
the streets of cities, when the steam locomotive will be as much of a curiosity
as the old lumbering stage-coach now is. We need not concern ourselves
with these speculations, but we are interested in the question of the feasibility
of connecting the cities of New-York and Brooklyn by means of a Pneumatic Railroad.
Those interested in this enterprise are so confident of success that they
ask no more fiom the Legislature than the privilege of being allowed to
undertake it. Almost any thing is possible to modern engineering, providing
money enough is furnished. It is of course possible to connect Brooklyn
with New-York by an underground steam railroad; but the cost of such an
undertaking would be so vast, and the difficulty of availing ourselves of
steam communication buried in the earth so great, that this scheme may be
dismissed as visionary or useless.
Now let us briefly state the advantage the one kind of locomotion has
over the other. Steam railroads are costly in their construction and in their
working, mainly because of the engine by which the motive power is generated. An ordinary locomotive with its tender weighs thirty tons; bridges,
viaducts, railroad tracks, cars, etc., must be made strong enough to bear the
weight, the wear, and the jar of this vast machine. The pneumatic train is
propelled by a motive power existing everywhere.  It weighs nothing.
Thirty tons have not to be moved, as in the case of the steam-engine, before a
feather's weight can be stirred. The light pneumatic car can be driven up
any grade, and can be made to turn the corner of a street as safely as a
horse-car. Assuming the starting-point to be at the City Hall in Brooklyn,
the tunnel need not be four feet under Fulton street, and following the grade
of the street until it reaches the tunnel in the bed of the East river, it will
ascend the grade on the opposite side of the bank to the City Hall in NewYork with any velocity that may be required. On a line fiom these two
points it is calculated that twelve thousand persons per hour could be conveyed from one city to the other, the time of each trip being within two
minutes. Access to either end of the line would be easy, for, as no grading
is required, the car need not be more than ten feet below the surface. The
expense of connecting these two points is estimated at a mil-lion dollars.
The cost of the bridge, at the very least, will be seven millions. Or in
other words, seven lines of road at seven different points may be constructed
for the cost of the bridge. The latter can not be built within seven years,
even if the capital required was ready to-morrow; the Pneumatic Dispatch
road can be completed within a year.
If any body should deem the scheme to be visionary, his opinion may be
shaken by the fact that an almost precisely similar enterprise is now under
way in London, with the view of connecting, under the Thames, the two
sections of that metropolis. The London scheme is a convenience, for the
Thames is spanned by a dozen bridges at different points. The scheme of
connecting the twin metropolis is a necessity. It seems to us that the
Pneumatic Dispatch as fairly promises to meet it as any scheme which has
yet been discussed. We now invite discussion for it, and we have no doubt
we shall be able to answer any objections which may be offered against it.




THE PNEUMATIC DISPATCH.                     81
NOVEL TUNNEL EXCAVATOR, FOR RIVERS AND LAKES-DESCRIPTION BY
THE INVENTORS.
HAVING spent much time and thought in devising a plan for laying a
tubular tunnel for railway and common roads under rivers and lakes, we
have finally matured the plan we now propose to place before the public,
hoping it will be examined by all who are interested in accomplishing the
great object for which it is intended.
This plan contemplates laying a cast iron tube, eighteen or twenty feet
in diameter, being in segments and rings, each segment being a sufficient
length so that ten of them shall form a ring three feet in length, each segment to be cast one and a fourth inches thick, with a flange three inches
wide, turned at right angles toward the centre of the tube, flange also to be
one and a fourth inches thick.
In approaching a river or lake, we propose first to survey and examine
the ground by boring, to ascertain the nature of the deposits, endeavoring
by this method to avoid rocks, boulders, or other obstructions. Having
completed the survey and established the grade, we now commence the
work at a point above high water mark, bolting the segments together with
lead joints, bolts passing through the flanges horizontally on the inside of
the tube. It will here be seen that these flanges form rings entirely around
this great tube, also ribs lengthwise, giving it great strength. We continue
to bolt the rings together, forming this tube, proceeding down the grade until we reach a point where the water begins to interfere with the work.
Here we introduce a pump, and continue the work by the common process
of excavation, until the pump is found to be insufficient. Here we will
cease the excavation, and continue the pumps at work. We omitted to say
in our description of segments, that they are to be thoroughly coated with
hard pitch, or cement of some kind, making a smooth surface on the outside.
We here apply a sliding-coffer eighteen or twenty inches larger than
the main tube, by about twelve feet in length, made of boiler iron, watertight, with a flange at its open end, eight or ten inches wide, turned at right
angles toward the centre of the tube, with a follower of equal size and
width of the flange, with bolt holes corresponding with the holes in the
flange; this follower is to be placed inside of the coffer, some eight inches
from the flange, and between which are laid six or eight inches of rubber.
Having placed this follower and rubber, we now bolt through this rubber
from flange to follower. We now place the coffer over the mouth or end
of the tube, and slide it back some three feet; we then draw upon these
bolts which pass through the rubber, making a water-tight joint on the
surface of the tube. We now lay a portable track on the inside of the tube,
connecting with circular cross-ties, which are bolted to cast iron staunches
four inches square, standing in two rows, three feet apart lengthwise, by
ten or twelve feet cross-wise, and connected at the top by circular crossties, forming an internal frame-work of immense strength. This portable
track is to be laid eight feet wide, each rail to be three feet long, to extend
from one tie to another. On this track will be placed a great supporting
car eighty feet in length, made of wood, with three sets of timbers running
the whole length, being bolted and braced so as to make it of great strength
and weight, and placed on low wheels, on this portable track. On this
great car will be placed a boiler and engine of sufficient power to do our
work.
We will now introduce what we will call a great boring shaft, eighteen
inches in diameter at its forward end, and eight inches at the back or rear
end, and forty feet in length. This shaft is passed through the centre of




82                   THE PNEUMATIC DISPATCH.
this sliding-coffer, with a packed joint, and placed upon the supporting car.
Upon this shaft, and in front, outside of this sliding-coffer, is placed a
dredging-wheel, of equal size of the coffer, made of wrought iron and steel,
cased up front and backside with plates of steel or iron, and provided with
steel lags in front, and on the verge, in form of the furrows on a mill-stone.
On this same shaft, inside of the coffer, and close to the journal, is a driving wheel, twelve or thirteen feet in diameter, and into it will ply a pinion
and shaft six inches in diameter, running back to the engine at the rear end
of the supporting car.
We now place upon the track, at the back end of this car, a portable
tooth-rail, into which will ply a cog-wheel, on a system of back-gearing and
feed screw, so as to multiply the power to any desired extent. We insert
in the upper side of this sliding-coffer an air spout running any distance
necessary to pass above the water. This spout is for purposes of ventilation,
and escape of steam and smoke of the engine. Having attached the engine
to the pinion-shaft by whatever back-gearing is necesary, we are now ready
to stop the pumps, and let the water in; but, before we proceed to work, we
will lay down the regular, permanent track, so that a construction train can
pass in or out with material and fuel. We omitted to state above that this
boring shaft is on a pivot-bearing at its forward end, and sliding-bearing at
its back end, so that it can be adjusted in a change of the grade.
Having all our machinery in readiness, we now get up steam, start our
dredging-wheel, excavating that portion of the ground which is above the
water line, by common process, leaving the balance to our dredging-wheel.
As this turns, it will be seen, by our description, that this car moves forward, it being connected with the sliding-coffer by four powerful and adjustable arms, the whole moving together as one body. The progress will
be slow, say six revolutions per minute; while we move forward, say one
sixteenth of an inch to each revolution of the wheel, varying according to
the nature of the excavation. As fast as we gain three feet we bolt in one
ring of our main tube. When we reach a point of sufficient depth of water,
a floating dredger is used, immediately in advance of our dredging-wheel,
so as to keep the top of the wheel above the ground. We now continue
down the grade, sinking deeper into the water as we proceed, pressing forward with unlimited power, and by the action of this wheel against the
bank, carrying up the earth at each revolution; mixing with the water, it
will become liquid and pass away, leaving us a space of one sixteenth of
an inch to each revolution. We speak of this progress as the slowest rate.
We are very confident we can progress as fast as the construction can go
on. We will now proceed down the grade, adding ring after ring to our
tube, until we reach the lowest point in our specifications, which should be
just the thickness of the tube below the bottom of the river. Here we
change our segment pattern, so as to come to a level, and change back to
straight segments, proceeding on to the opposite side of the river, where the
changes will again be necessary.
This, it will be seen, is a system of progression. If we can gain one
foot, we can go any distance. We have for a base this great iron structure,
weighing two tons to the foot, completely buried in the ground, fiom which
we operate with unlimited power. We have provided for displacing the
water. The plan for displacing the earth has been passed upon by some of
the best engineers in the country, and considered ample. In this hasty description we have omitted many things which might be said in favor of this
plan, but hope its general principles may be understood.
In conclusion, we desire to say we have spent years to devise means to
accomplish this great object, and believe we have succeeded. From estimates we have made we are satisfied the work can be done for less than




THE PNEUMATIC DISPATCH.                     83
any form of an iron bridge. The tube can be coated on the outside, and
cemented on the inside, which will insure its durability, so that when once
laid it may be a safe commercial highway, through which may pass a hundred generations. It will be easy of approach at either end, being only
just low enough to leave the river unobstructed. The approaches may be
made of other material, if found cheaper; but we are of the opinion that
iron will be found the cheapest. Our estimate on an eighteen foot tube, all
complete, at two tons per foot, at eighty dollars per ton, would be a hundred
and sixty dollars per foot; this will be about sixty-six per cent of the entire cost, when ready for use. Now, taking into account the great advantage of a permanent tunnel passing under a river, leaving the same unobstructed, we hope it will command the attention of enterprising men who
are so desirous of a better way of crossing our streams; and, especially,
the attention of scientific men everywhere. We ask them to examine the
plan carefully with regard to its merit or demerit.
T. A. FISHIER & SON,
Beardstown, Ill.








GENERAL INDEX.
Page.                                      Page.
Accounts of the Pneumatic Dispatch in     New-York Tribune, views and reports
London......    10, 12, 13  of.......... 42
Blowing machinery, description of.. 13  New-York City, street traffic of... 55
Brooklyn Daily Eagle, views and re-       North River, proposed pneumatic tunports of..........   77    nel under......... 57, 69
Croydon Atmospheric Railroad.. 5, 20  Novel tunnel excavator.....   81
Comparison of pneumatic and locomo-       Pneumatic tunnel at Sydenham... 20
motive systems......   67  Pneumatic railway tunnel under the
Comparative economy of pneumatic rail-      Thames......... 25
roads.........           30, 31  Pneumatic railway under the streets of
Early atmospheric railways... 18, 23    London...........                23
Engineering, views and reports of..70  Pneumatic vs. Locomotive railways.. 29
Elevated pneumatic railway.... 46     Pneumatic railways in Switzerland..33
East River, proposed pneumatic tunnel     Pneumatic   railway in the    United
under.......... 57, 69                   States, first trial of.....      33
First public trial of the Pneumatic       Pneumatic Postal Dispatch. 35, 38, 42, 48
Dispatch, Battersea Fields... 7, 9  Projected pneumatic railways. 35, 36, 44
Frank Leslie's Illustrated Newspaper,     Practical Mechanics' Journal, views and
views and reports of..... 16, 36     reports of.......... 12
First trial of pneumatic passenger rail-  Passengers, number carried, Brooklyn
way, Sydenham........ 18                 Ferries....... 69
First public trial of pneumatic railways  Report of the Directors, Pneumatic Disin United States. 33, 34, 35, 36, 41, 42  patch Co., London.......         11
General principles of pneumatic dis-      Scientific American, views and reports
patch............                   5    of.... 9, 27, 33, 41, 46, 57, 71, 75
Grades, the steepest easily ascertained 20, 22  Steam Tunnel Excavator, Fisher's.. 81
Holborn-Street Station, opening of.. 15  Sub-aqueous pneumatic dispatch.. 28
Heating and ventilating   pneumatic       Stopping at way stations.....       45
cars...........46   The Engineer, views and reports of..  9
Inspection by the Postmaster-General. 10  Thames Archway Company.... 58
Illustrated News, views and reports of 22  Taking letters from the lamp-post.. 54
Incorporation of Whitehall Pneumatic      Tunnel, sub-aqueous, various plans for 58
Railway........... 23 " Trevethick's, drift under the
Is a pneumatic railway feasible?.. 77            Thames..... 58
Laying down of the Pneumatic Dis-            "    brick, plan for......         59
patch in London........ 10          cast iron, Trevethick's... 59
Load and velocity of car at Battersea.  8  "    combined wooden, cement and
Mechanics' Magazine, views and re-                  iron.......      61
ports of.... 7, 10, 11, 16, 18, 23,29   "     Croton aqueduct..... 6
Medhurst's pneumatic railway... 18       "    Chicago, at......          70
New-York Herald, views and reports of 26     "    double........   62
New-York Times; views and reports of  33     "     De Sendzimir's river.... 71




86                 THE PNEUMATIC I)ISPATCH.
Page.                         Page.
Tunnel, Dixon's......... 75 Tunnel, Temporary iron and perma"   Experimental, under the        nent brick......  59
Thames.....  63   "   Thames.......      66
"   Fisher & Son's plan for.. 81  "  Wooden (Trevethick's)... 60
"   grooved stone.....  59  "   Wrought iron......   62
"   Holcomb's....... 73   "   Wyatt and Hawkin's. 
"   Rowland's......     71   "   Weymouth....... 69
"   second Thames..      68 Various facts concerning pneumatic
"   Sydenham, at.... 20  railways.4........45




ILLUSTRATIONS.
Page.
Arrival of Foreign Mails..................   56
Cast iron tunnels, Dixon's plan..............  76
De Sendzimir's Tunnel...................  73
Elevated Pneumatic Railway..................47
First Pneumatic Passenger Railway, Sydenham............  21
Holcomb's Tunnel....................  74
Inauguration of the Holborn Street Extension............  15
Lamp-Post Letter-Box....................... 54
Dneumatic Dispatch, applied to Postal Service..........  51, 52."      proposed  City Station..........    49
".    "   as erected at Battersea...............  6
It    "   receiving and delivering Station..........  53
Pneumatic Postal Dispatch....................39, 40
Pneumatic Passenger Railway...............  37
Section of Pneumatic Railway under Thames.............  32
Stopping Pneumatic Cars at Way Stations..........     45
Street Tunnels, Dixon's plan...................  76
Pube of the Whitehall Pneumatic Railway..........  28