446 



Mr. Anderson 



[April 9, 



The action of the ram is as follows : — The outer valve C which 

 opens inwards, is, in the first instance, held open, and a flow of water 

 is allowed to take place through it down the pipe and chamber. The 

 valve is then released, and is instantly shut by the current of water 

 which is thus suddenly stopped, and, in consequence, delivers a blow 



Fig. 4, 



similar to that produced by the fall of a hammer on an anvil, and 

 just as the hammer jumps back from the anvil, so does the water 

 recoil back to a small extent along the pipe. 



During this action, first, a certain portion of water is forced by 

 virtue of the blow through the inner valve D, opening outwards, into 

 the cork vessel, and so to the delivery pipe, and, instantly afterwards 

 the recoil causes a partial vacuum to form in the body of the ram and 

 permits the atmospheric pressure to open the outer valve C and re- 

 establish a rush of water as soon as the recoil has expended itself. 

 In the little ram before you, this action, which it has taken so long 

 to describe, is repeated 140 times in a minute. 



The ram is now working, you hear the regular pulses of the 

 valve, and you see a jet of water rising some 10 feet into the air. I 

 throw the electric light on the water, and I ask you to notice the 

 regularity of the flow. You can, indeed, detect the pulses of the 

 ram in the fountain, but that is because I am only using a regulating 

 vessel of the same capacity as that generally used for air, and you 

 will recollect that 44 per cent, of the substance of cork is solid and 

 inelastic. By closing a cock, I can cut off the cork vessel from the 



