ACCLIVITIES BY THE PNEUMATIC RAILWAY, 
61 
because of the danger connected with the 
common system, will be entirely removed, and 
a great improvement may be confidently cal- 
culated upon in the important item of passen- 
ger traffic. 
“ When it is considered that 5^ the im- 
proved system a line of road may he formed 
and constructed, for, at the most, two- 
thirds, and in some cases, for one-half the 
expense involved hy the common system ; 
and that such a railway can he maintained 
and worked with far greater speed, and 
infinitely greater safety, for three-fourths 
less than the common system costs ; and 
that therefore passengers and goods may he 
conveyed at one-half the price ivhich the 
common system demands, and then yield a 
far competition with the As- 
sociation will be wholly out of the question. 
“ As any degree of speed cdJi be obtained 
by the improved system with the most per- 
fect safety, and without the disadvantage, not 
to say danger, arising from great velocity on 
the common method, a single line on the new 
system can be made, by the reciprocating 
plan proposed, to effect as much transit as 
can be effected by the use of a double liae on 
the former, while the cost will thereby be 
lessened nearly one-half. Hence communi- 
cations that may not warrant the expense of 
a double line of railway, may be advantage- 
ously occupied vyith a single line ; number- 
less lines are in this manner open to the 
application of the new system, which the 
common method will not permit of being- 
attempted, 
“ As the invention affords the means of 
applying the power to the common railway, 
the proprietors of such must soon be found 
anxious to avail themselves of its advantages ; 
and thus all the railroads in the country may 
soon become tributary to the Association, 
while the interests of the various concerns 
themselves will be materially improved by its 
adoption.” 
Prefixed to the prospectus there are two 
views, of which those on the front page of our 
present Number are reduced copies ; Fig. 1, 
representing the Pneumatic Railway, as it 
would appear in actual operation ; and Fig- 
2, a sectional view of the Railway Cylinder, 
exhibiting the internal arrangement. 
OPINION OF DR. LARDNER. 
I have read the specification of the patent 
for the Pneumatic Railway and the accom- 
panying papers, and have also examined the 
drawings and models which have been sub- 
mitted to me by Mr. -Hocking.* 
Two methods have been heretofore em- 
ployed for rendering steam power available 
in transport upon railways ; one by causing 
a travelling or locomotive engine to move 
with the load which it draws, the other by 
constructing, at intervals of about a mile 
and a half, stationary steam-engines, the 
power of which is transmitted to the load by 
a rope carried along the road upon rollers or 
* Professional Director of undertaking the.— • 
Ed. xM. M. 
sheaves placed between the rails. 1'he train 
being attached to this rope is drawn by the 
power of the engines from station to station. 
The object of the Pneumatic Railway is to 
substitute for the rope a partially exhausted 
tunnel, to employ the fixed steam-engines to 
work air-pumps by which a rarefaction of the 
tunnel shall be maintained, and to cause the 
trains to be tracked upon the railway by 
connecting them with a diaphragm or piston 
placed in the interior of the tunnel, so as to 
have that part of the tunnel in advance of 
the piston rarefied by the engines, while that 
part behind the piston is open to the atmo- 
sphere. An effective impelling power is thus 
obtained equivalent to the difference between 
the pressure of the atmosphere on one side of 
the diaphragm, and of the rarefied air on the 
other. ! ! ! 
Of the practicability of this project, I think 
there can be no doubt. d he working of 
large air-pumps, by an adequate moving 
power, and the rarefaction of air in tubes or 
tunnels by such means is not a new idea. It 
was suggested by Papin in the latter end of 
the seventeenth century, and was even pointed 
out by him as a means of transferring power 
to a distance, without the loss by friction and 
other causes consequent upon the use of ropes, 
or other ordinary means of transmitting 
force. It is, in fact, a well understood prin- 
ciple in physics, that whatever moving force 
be expended in producing the rarefaction of 
air in a cylinder or tunnel, must necessarily 
be followed by a corresponding force on the 
other side of a diaphragm moving air-tight 
in that tunnel, and exposed to the free action 
of the atmospheric pressure. In the present 
case, supposing the structure of the valvular 
cord and the pneumatic piston to be perfect, 
the opposite side of the diaphragm will al- 
ways be pressed by an effective impelling 
force, the amount of which may be calcu- 
lated upon these principles. It will, of 
course, be perceived that no original moving 
power is obtained from the tunnel, or from 
the rarefied air; the rarefaction gives back 
the power expendedby the stationary engines, 
and nothing more; and the tunnel must 
therefore be regarded merely as a substitute 
for the ropes in the common method of work- 
ing railways by stationary engines. But it 
is evidently attended with several advantages 
in comparison with the latter. A very large 
proportion of the moving power of stationary 
engines worked by ropes is intercepted by 
the resistance from the weight and friction of 
the ropes, sheaves, barrels, drums, &c. All 
such waste of power is removed by the pneu- 
matic tunnel. 
The original expense of ropes, and then- 
wear and tear, would be likewise saved. 
Some notion of the extent of this saving may 
be collected from the following facts : — when 
the Liverpool and Manchester Railway was 
about to be brought into operation, a question 
arose as to the expediency of working it by 
stationary engines, and estimates of the ex- 
pense were made by competent engineers, d he 
total amount of capital to be invested in mov« 
ing power was estimated at about 120,000/. ; 
of this above 25,000/. was devoted to ropes. 
