Chap. 3.] Pumps. 447 



which a kind of ftopple I, called the pifton, is made to 

 flide, or move up and down. The pifton is put in 

 motion by means of a rod of metal X x, at the extre- 

 mity of which X the handle is placed, and elevated by 

 the lever X Y, or by fome other contrivance ; to this 

 is annexed a pipe AT (Plate VII. fig. 3.) to con- 

 duct the water to the height required ; and, laftly, the 

 fuckers S s. 



There are feveral kinds of pumps; fome are called 

 fucking pumps and others forcing pumps, and there 

 are others which are at the lame time both fucking and 

 forcing pumps. 



The raifing pump is compofed of the body of the 

 pump A B, (Plate VII. fig. 3.) /to the lower part of 

 which is affixed the end of a pipe B N, open at the 

 bottom, or (which is ftill better) pierced with holes 

 its whole length, in fuch a manner that large piece's 

 of dirt and rubbilh may be prevented from entering 

 the body of the pump. At the union of this end of 

 the pipe with the body of the pump is placed a valve 

 or fucker s, which, when raifed up by the preflure of 

 the water beneath, permits the fluid to afcend into the 

 body of the pump, but which, by being prefled down 

 again by the action of the pump, prevents effectually 

 the efflux of the water by the fame aperture. In the 

 body of the pump there is a box or pifton I, pierced 

 quite through, furnifhed at the upper end with a fucker 

 S, and joined at #, by the affiftance of a head fomewhat 

 in the form of that of a pair of compafTes, to the rod 

 x X, which enables it to act by the aid of a le^er 

 X Z Y. At the upper part A of the body of the 

 pump is placed the raifing pipe A T, which has its 

 fpout at T. This pump ought to be placed in a well 

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



pump 



