80 Mr Hunter on an Improved Self-acting Pump, 
C, a cistern at which water is required. 
D, a metal (w^ater proof) box, 12 inches square and 4 inchesi 
deep, placed within A, and near the top of it. 
E, a pipe of half inch bore, leading from the top of A to the 
bottom of F. 
F, a metal box, similar to D. 
G, a pipe of half inch bore, leading from the top of F to the 
top of D, the upper part of it being above the level of B. 
H, a pipe of half inch bore, leading from the bottom of D to 
the bottom of C, and made as lono' as from R to S. 
I, a valve (opening upw^ards) at the mouth of the pipe H. 
K, a valve (opening upwards) at the bottom of F). 
L, a valve (opening upwards) at the bottom of F. 
M, a pipe which takes the overllov/ing water of E to 
N, a small light pan, wliich, if filled with water, bears down 0. 
O, a lever, which, when pressed dowai by N, opens the valve L. 
F, a pin, to which is fastened a piece of chain, having at its end 
a flat piece of leather, which, when N is pressed dowm, leaves 
it, and opens a hole at Q. 
Q, a hole in the bottom of N, which must be made of a proper 
size, for the purpose of letting the water escape from N,hn 
the same time that is required for D to be filled with water 
through K. 
The following is the mode in which the pump operates. 
The vessels D and F being full of air, the water of A runs 
into E, expels the air from F, through G and D, to I, and fills E, 
F, and G to the level of B. It then runs over at R into the 
pipe M, fills N, wdiich is borne down by the weight of water, 
and opens L and Q, as above described ; the vessel F then emp- 
ties itself at L, is filled with air from D through G, and D is 
filled with w^ater through K. In the same time, N is emptied 
through Q, and returns to its place, allowing L to shut, and 
leaving F and G full of air. The water continues running 
through E, expels the air from F through G into E, which air ex- 
pels the water from D through H up to C, until F and G are 
filled with water and D with air, when the machine is found in 
the same state as at first, F and G being filled to the level of B. 
