106 
horizontal, makes comparatively little difference in the 
length of the recoil. With a 12-ton (300 pounder) gun a 
service charge of 30lbs. of powder gave a recoil of 4 ft. 
5in.; with a battering charge of 43 lbs. the recoil in- 
creased only to 5 ft. rin.. If the charge is heavy, or if the 
slope favours the recoil, the carriage will not go much 
further back than if these conditions are reversed. But 
it will do so more rapidly. The space travelled over is 
not much greater with the violent recoil, but it is done in 
a shorter time. It is also worthy of notice that quick 
burning powder, such as the rifled large grain, does not 
give so long a recoil as the slow burning ones, such as 
the pebble and pellet powders, although it acts much 
more violently on the gun; the reason is that the recoil 
is more rapid. Few machines give so striking an illus- 
tration of how important an element is time in work to be 
done, and how much force is to be increased if anything 
is done more rapidly. The strength of one man is quite 
sufficient to push in or pull forward the piston of the Hy- 
draulic Buffer, because he does it quietly, “ takes his time 
to doit.” The force of a 25-ton gun, recoiling from the 
discharge of 7olbs. of powder, and a 6o00lb. shot ex- 
hausted itself in doing the same, because it does it so 
quickly. 
NATURE 
[Fune 8, 1871 
In fact, the ease with which the hydraulic buffer permits 
slow motion is one of its disadvantages, and prevents its 
application to sea service carriages, as it would not 
keep the carriages from moving as the ship rolled. A 
modification to obviate this difficulty has been proposed. 
It consists of a solid piston (without holes), and the back 
and front ends of the cylinder are connected by a pipe 
through which the water is driven by the recoil. The 
motion of the water can be stopped altogether by the stop- 
cock till the gun is fired, and the area of the orifice through 
which the water is to pass can also be regulated by it. 
The resistance of the water, and consequently the 
pressure on the cylinder from the recoil, is not uniform. 
It becomes greatest at the moment when the air receives 
its maximum compression, before the water attains its 
highest velocity in passing through the holes in the 
piston. At this point the force of the recoil is felt as a 
severe strain upon the cylinder and the platform which 
holds it. This destructive action of the recoil of heavy 
guns not only upon platforms, pivots, and racers, but also 
upon the foundations on which they rest, is one of the 
great difficulties with which modern military engineering 
has to grapple. To remedy this disadvantage by causing 
the recoil to meet with a gradually increasing resistance, 































































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oe 
1 Be 









9 oF, olla) ste aa oo 8% 
| NT SO 


AP cylinder ; c end of piston-rod attached to carriage ; c’ end of piston-rod after recoil ; p E slide or platform. The dotted lines show the position 
of the carriage and gun after recoil. 
so that its force may be felt as acontinuous pressure, and } 
not at any point as a shock or blow, the following very 
ingenious arrangement was proposed by Mr. H. Butter, 
Chief Constructor in the Royal Carriage Department. 
It consists in placing along the length of the cj linder and 
through the holes in the piston four tapering rods, the 
largest extremities of them being at the rear end of the 
cylinder, and being of sucha size as there to fill completely 
the piston holes. These oritices and also the whole cylinder 
must be larger than where the rods are not employed. | 
‘The effect in this case is that, as the area for the water to 
flow through the piston is continually diminishing as the 
holes get further along the rods, the force of the recoil has 
to impart a continually increasing velocity to the water, 
and is at no point feltas ashockor blow. The resistance, 
slight at first, gradually increases throughout the recoil, 
and so exhausts its force not at any one point, but through- | 
out the whole of its course. 
It has been suggested, and it is a consummation most | 
devoutly to be wished, that the Hydraulic Buffer might be 
applied to railway trains so as to take away the destructive 
effects of a collision. A train of carriages separated by 
Hydraulic Buffers would, if suddenly stopped at a high 
speed, simply close up, the piston being driven in, and 
the force of the collision would exhaust itself in the motion 
given to the water in the cylinders. Some practical 
difficulties stand in the use of this application of the in- 
vention ; principally, that the length of the piston rods 
would inconveniently increase the length of the train. 
But there are none which might not be overcome by a 
little ingenuity ; and the great importance of the object 
to be gained makes the neglect of any promising means 
to attain it highly culpable. However, slowness in taking 
up new ideas (especially if they do not immediately add 
to dividends), is not altogether a peculiarity of Government 
departments. 
A very interesting pamphlet on this subject has been 
published by Colonel Clerk, in which Mr. Butter shows the 
work done in the Hydraulic Buffer, by comparing it with 
the moment of a similar weight of water falling through 
such a height as to give it the same velocity as that with 
which it passes through the holes in the piston. By this 
ingenious comparison he ascertained that a locomotive 
engine, weighing 50 tons, and moving at the rate of 30 
miles an hour, would be brought to rest in the space of six 
feet by two Hydraulic Buffers of 12in. diameter. “ There 
are,” Colonel Clerk remarks, “two important problems to 
be worked out by the railway authorities :—(1) to have no 
railway collisions ; (2) if they must sometimes occur, to 
render them as harmless as possible ;” and it is with the 
| second that he deals. The plan which has been so suc- 
| cessful in meeting the violence of exploding gunpowder, 
should, at least, have a trial in a case of far greater im- 
portance—security to life in railway collisions. To refuse 
| this, on account of a few difficulties or inconveniences, 
seems a sin against Nature herself. 

