Farms and Villages. 
53 
■wards and communicating with a regulating vessel E, which is 
'usuallv filled with air. Immediately beyond the inner valve 
is inserted a delivery pipe F, which is laid to the spot to which 
the water has to be pumped. 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 
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 to a small extent along the pipe. This 
external aid must be repeated several times at first, starting a 
ram, till sufficient pressure is got up in the air-vessel to allow 
the working to go on automatically. During each stroke, first, 
a certain portion of water is forced by virtue of the blow through 
the inner valve D, opening outwards, into the air-vessel, and so 
to the delivery-pipe, and instantly afterwards the recoil causes a 
partial vacuum to form in the body B 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 this way a succession of rushes, stoppages, and recoils 
take place many times in a minute, a certain quantity of water 
flowing to waste from the outer valve C, and a smaller portion 
passing the inner valve D into the rising main. 
One very important adjunct is the " sniff- valve " G. Some 
3finds of water absorb air very readily, especially when under 
pressure ; hence in such cases the air in the vessel E would soon 
become absorbed, and the ram would cease to work for want of 
the elastic cushion, were it not for the sniff valve G, which is 
a very minute valve opening inwards. At the moment of recoil, 
when a partial vacuum is formed in the body B of the ram, 
bubble or two of air is drawn in through the sniff- valve, and 
finds its way through D into the air vessel. It is important, for 
the efficiency of the ram, that the quantity of air admitted be as 
small as possible. 
Sometimes it is convenient, in order to take advantage of 
a scanty supply of water in summer, to place a ram so low that 
it becomes covered by back-water in flood-time. A good ram 
will work under such conditions ; but, if the water be of a quality 
requiring the addition of air, a sniff valve will be inoperative, 
because it will be submerged ; in such cases the air vessel can 
be filled with ordinary bottle-corks, a stout grating being inserted 
between the neck of the air vessel and the corks. The constant 
variation of pressure, and the consequent movement of the corks, 
•causes them gradually to lose their elasticity, so that they will 
