The Sun.
London, England, 1863-02-10 00:00:00

PNEUMATIC DESPATCH COMPANY.

The efforts of our engineers to make air do duty
as steam, to utilise the law by which air rushea in
with great force wherever a partial vacuum is
created, has at last in this company resulted in a
very practicable scheme by which parcels are trans-
mitted by a kind of air•post, somewhat after the
same fashion as that by which the late Mr. Brunel
tried to propel cars on his atmospheric railway.
There is, however, this important difference be-
tween the two plans, that, whereas Mr. Brunel's
looked very well in theory, it was found all but
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mile has been laid from the arrival platform of
the Easton Station to the N th W
or - estern District
Post-office, in Eversholt-street. This length, though
quite sufficient to give a fair 'of
sample the speed
and power of this subterranean parcels' line, is, of
course, only the first step towards a regular series
of these " despatches," which are
hereafter to
be laid so as to connect together all the great
railway stations and chief district post-offices.
Before entering further on the subject of
these future extensions we must explain what
the pneumatic despatch means, and how it is
carried into practice. The " tube," as at present
laid, is very like an elliptical gas main, 33 inches
high by 30 wide, and laid at an average depth of
about nine feet below the road. The pipes of which
it is composed are made in nine feet lengths, with
socket joints filled in with lead so as to keep them
perfectly airtight, and on the inside, at the bottom.
of the tube, are cast iron rails, like miniature rail-
way metals, two feet apart. The car to run on
these is made of wrought iron, weighs nearly Bowt.,
is about eight feet long, and runs upon four wheels,
29 inches in diameter. In this short enumeration
we have described almost the whole of the plant
and rolling stock required for a pneumatic despatch
railway. The car we have spoken of, when placed
in the tube on the rails, is blown from end to end,
backwards or forwards, as it is wished. The way
in which this is accomplished is as simple as it is
ingenious. Air, like all other substances in nature,
has a weight of its own, which, though very light
—only 117 oz. to the cubic foot—is nevertheless
enough to bring it under the influence of the laws
of centrifugal force, which give it a tendency to
fly off with more or less pressure, accord-
ing to the velocity with which it is whirled
round from a centre. This inevitable law is turned
to good account in working the parcels' despatch.
At each end of the tube we have described a hollow
iron wheel is erected, working in an airtight box.
This wheel is 21 feet in diameter, with a thickness
of about two feet at the nave or centre—a thickness
which gradually diminishes towards its outer cir-
cumference, so as to give it the same cubical con-
tents at the rim as at the middle. This wheel is con-
nected with a steam-engine of about 17-horse power,
which turns it at a velocity of from 70 to 90 miles
an hour, when the air which is drawn in through its
hollow centre is thrown off from its periphery with
a force which gives a pressure of from five to seven
ounces on the square inch, very nearly the pressure
of a hurricane, and all of which, by opening a valve
at the end of the tube, is driven through it with
almost irresistible velocity. The cars we have
already spoken of, when on the rails in the tube, fill
it almost completely, and expose a surface of nearly
five square feet to the blast. They are therefore
driven along it at the rate of nearly 30 miles an
hour. In literal fact the cars are either drawn or
driven along by what is virtually a chain of air
which costs nothing and of which the weight and
friction aro almost nil. Nothing, in fact, can well
be simpler, cheaper, or more effective than the
whole apparatus, and the ease and certainty with
which the wheel does its duty and sends one or
more cars, heavily laden, flying before it is asto-
nishing. At present, as we have said, the line is
only laid for a short length, but already by this
route the mail begs for the North-Western district
aro despatched on the instant of their arrival at
Euston-square, and though for this small distance
the saving of time effected amounts to only a few
minutes, yet such a saving promises to become im-
portant in proportion as the line is ex-
tended. It is intended to lay down forthwith
a line of 48-inch tubes to form pneumatic stations
in connexion with the Camden-town station of
the London and North-Western Railway ; a cen-
tral site in High Holborn ; the Smithfield Neer
Market; in Gresham-street, in connection with the
large carrying firms for goods and parcels; the
General Post-office, Covent-garden market, and the
new terminus of the South-Eastern Railway at
Charing-cross. This entire line, with its branches,
will be about five miles in length. Its cost, laid
complete, including stations, machinery, compensa-
tions, and purchase of sites, is estimated at
£131,000, and the whole, it is said, may be com-
pleted and brought into practical use within a year
from the commencement of the works. On this
outlay the directors calculate upon giving a net divi-
dend of not less than 10 per cent. per annum, but
on this point we can say nothing. It is stated
that Messrs. Pickford alone convey 400 tons of par-
cels a day through London at a cost of 9d. per ton
per mile, whereas the Pneumatic Company could
afford to do the same work quicker at a penny a ton
a mile, and yet be large gainers by the transaction.
But, paying or not paying, the public are sure to
gain from the labours of the new p
com any by get-
ting their parcels transmitted throughout London
in a tenth of the time and for a tenth of the cost
now expended in sending them from one district to
another. Between the pneumatic despatch and tho
subterranean railway the days ought to be fast ap-
proaching when the ponderous goods vans which
now ply between station and station shall disappear
for ever from the streets of London. If only this
result is brought about, the promoters of the two
schemes may be considered in the light of public
benefactors, and from this point of view alone we
are inclined to wish success to the exertions of the
Pneumatic Despatch Company. The engineers of
the undertaking are Mr. Rammel and Mr. Latimer
Clark.—Times.