450 tfbe forcing Pump. [Book VII. 



part, and with a fpout O at its upper extremity. This 

 pump, as. well as the preceding, ought to be immerfed 

 in a well or bafon in fuch a manner that the body of 

 the pump C D fhould be entirely under the furface of 

 the water A A. 



The water fills the body of the pump by falling 

 through the aperture C, and by pafling over the pifton 

 K, the fucker of it S, confidering its pofition, will 

 natundly open. If the pifton K is loweredj by placing 

 the lever Y X Z in the pofition y u Z, the refiftance 

 of the water againft the fucker S will clofe it imme- 

 diately. This water then, being incapable of repaffing 

 above the pifton, is forced up the pipe A O, by 

 raifing up the fucker s. As foon as the pifton is 

 raifed again, the fucker s is clofed by the preffare of 

 the water which is above, and the fucker S is opened 

 by its own weight. A new mafs of water then paflTes 

 below the pifton, which by a fecond depreflion of the 

 pifton, is forced to pafs, like the firft, into the pipe 

 AO ; fo that by a certain number of ilrokes of the 

 pifton, that pipe becomes full of water, which in then 

 idifcharged at the fpout O as in the pump already de- 

 fcribed. If the piftons in both of them are of the 

 fame diameter, and the raifing pipes of the fame per- 

 pendicular height, the weight of the two columns of 

 water will be equal, and the two pumps will require 

 the fame power to work them j for in that cafe it re- 

 quires the fame power to elevate the pifton charged 

 with a column of water as it does to force the column 

 of water by means of the pifton. 



The fucking* pump (Plate VIII. Fig. i.) is com- 

 pofed of the bo$y of the pump E F, open above, and 



* So called, becaufe.it was originally fuppofed, but erroneoufiy, 

 to -adl by fuftion* 



with 



