Chap. 3.] <The Fire Engine. 457 



the pump in aftion. I believe this is at prefent the 

 moft ufual form of what are called forcing pumps in 

 this country. 



The fire engine is" an hydraulic engine, which may 

 be clailed with the pump that 1 have now defcribed. 

 It is at once a fucking and forcing pump, but has 

 a continued jet y or ejecting pipe, though it has only 

 one body. The effential parts of this pump are 

 compofed, like the compound pump, (Plate VIII. 

 Fig. 2.) with this difference, that its afpiration pipe 

 is much fhorter, and that inftead of a folid raifing 

 pipe it has a leathern tube of a convenient length. 

 This pump (Plate IX. Fig. i.) is then compofed of 

 the body of the pump A H, open above, and to the 

 lower part is adapted the afpiration pipe H T. At 

 the union of this pipe with the body of t Ti e pump is 

 placed a fucker S, defigned to prevent the water, 

 which has once paffed into the body of the pump, 

 from returning into the bafon. In the body of the 

 pump is a pifton M, not pierced but folid, and which 

 is put in motion by the aid of a metal rod x X, and 

 of a lever Y X Z, v/hich has its fulcrum or point of 

 fupport at Z. Towards the bottom of the pump, in 

 the fide, is an aperture C, which is covered again by 

 means of a valve c /, of which the tail / is a Ipring, 

 and which is fixed on with a fmall fcrew. This 

 valve is defigned to prevent the water, which is ex- 

 pelled from the body of the pump, from entering 

 again when the pifton M is raifed. The body of the 

 pump is furrounded with a pipe A B D E, about two 

 or three inches more in diameter than the body of the 

 pump, and the intermediate fpace between them is 

 filled with air. To the lower part of this pipe, and 

 upon the fide, is adapted another fmall crooked pipe 

 R, furnilhed at the end R with a, fucker j, and with 



a fcrewr 



