234 Mr. F. J. Bramwell [June 13, 



saucer-shaped disc of copper, having thin edges. The pressure of the 

 powder speedily expands the disc, making its edges fit the bore, and to 

 some extent making them also fit into the rifle grooving. I may 

 mention in passing, that advantage is now being taken of the gas-check 

 as an implement to cause the rotation of the projectile, thus dispensing 

 altogether with the studs. 



Diagram 10 is a drawing of the wrought-iron gun carriage on 

 which by its trunnions the gun is supported : this carriage, lettered 

 «, bears on slides lettered h. The rear end of the slides is upon 

 a pivot, Z>', while the front end can be put upon any one of three 

 steps, the lower, middle, or upper, so that the slides may be horizontal 

 or inclined as desired. From the front of the carriage there depends 

 an arm c, to which is attached a piston rod cl, having on it a 

 piston e, travelling to and fro within the hydraulic cylinder /, 

 placed below the slide. By a handle g, when put into the position 

 1, water under pressure from an accumulator can be introduced into 

 the cylinder between the end d and the piston e, so as to drive the 

 piston towards the left hand, and thereby cause the carriage to move 

 and to run the gun inwards as shown by the arrow in full lines, until 

 stoi)ped by a buffer coming against a stop at y. When the handle 

 g is moved to 2, then the position of the valves is changed so as to 

 stop the inflow of water from the front of the piston, and other 

 valves are opened to allow an outflow, so as to admit of the 

 water under pressure flowing into the cylinder between its end h 

 and the piston e to drive the carriage towards the right hand as 

 shown by the dotted arrow, and thus to run the gun out. By the 

 foregoing mode, the gun, it will be seen, can be run both in and out 

 without the exercise of any manual labour. But the apparatus attains 

 not only this end, but the further one of checking the recoil which 

 arises from the discharge of the gun when loaded, and this it does in 

 the following manner. Connected to the rear end of the cylinder / 

 is a valve box Z, containing as many as six large safety valves loaded 

 by spiral springs to a pressure nearly double that which prevails in 

 the accumulator, so that when water from the accumulator is intro- 

 duced behind the piston e to run the gun out, these valves do not open ; 

 but assuming the gun to have been run out to the firing position and 

 to have been fired, then the recoil drives the gun back with great 

 violence, and thereby causes the piston e to press on the water in the 

 cylinder with such a pressure as to raise the safety valves notwith- 

 standing the load upon them, and to allow the water to escape until 

 the energy imparted to the gun and carriage by the recoil has become 

 expended in driving out the water through the loaded valves. The 

 resistance ofiered by the water under these circumstances is always 

 sufiicient to stop the recoil by the time that the gun has only made a 

 portion of its inward run, and the remainder of that run has to be 

 accomplished by putting the lever g into the position number 1, so as 

 to introduce the water under pressure between tlie cylinder end d and 

 the piston e. As a matter of fact when firing with powder, as soon as 



