SIX WILLIAM SIEMENS, F.R.S. 33! 



covered with an elastic valve, in order that, as the recoil took 

 place, there should always be the same amount of resistance per 

 square inch throughout the stroke, and that the gun might come 

 to an absolute stand the moment that amount of power was 

 consumed. Colonel Clerk, with whom he had principally to deal, 

 took up the idea warmly, and effected several modifications. He 

 wished to do away with the tail-rod, which was unnecessary in 

 his plan, in order to balance the area on both sides of the piston, 

 and he accomplished this by filling the cylinder with water and 

 air mixed. By that means an elastic resistance was opposed to 

 the recoil action of the gun, and the first shock was greatly 

 diminished. But this plan had its disadvantages ; for, as the 

 communicating orifice was invariable, it was never certain what 

 amount of pressure would have to be dealt with, and as the 

 thoroughfare was always open, the gun did not come to an absolute 

 stop. The authorities at Elswick, who clearly perceived this draw- 

 back, had now introduced a plan not very dissimilar to that which 

 he himself originally suggested, but going much farther than he 

 then contemplated ; for they proposed to drive the water by the 

 recoil through a loaded valve into a separate cistern, whence it was 

 to be forced by steam power into an accumulator to work the gun 

 forward. This plan was also susceptible of the power of propulsion, 

 a hand pump being applied to force the water from the front to 

 the back of the piston : or the loaded valve might simply be raised 

 while the gun-carriage was being pushed forward as usual. This 

 was a matter of secondary importance : and he did not profess to 

 judge whether it would be better merely to have the valve, and 

 to push the carriage forward, or to complicate the arrangement 

 by the addition of a pump. The pump would, he thought, 

 be found the preferable agency on board ship, especially in 

 working heavy guns. Colonel Clerk, in a pamphlet "On the 

 Application of Hydraulic Buffers, to prevent the destructive effects 

 of Railway Collisions," published in the year 18G8, handsomely 

 acknowledged the part which he had taken in the matter in the 

 following words : " In consequence of a suggestion made to me 

 last year by C. W. Siemens, Esq., C.E., F.R.S., to try the effect of 

 water to check the recoil of heavy guns, I submitted to the 

 Secretary of State for War a compressor or buffer on the above 

 principle. It has been tried with guns varying in weight from 



