1-4-6 



drtifaial Feuntains. [Book VII, 



IV. From objects of mere pleafure and ornament, 

 our attention is next folicited to an invention of emi- 

 nent utility, and of ancient date, though the modern 

 improvements are very confiderable even in this branch 

 of mechanics. 



Pumps are hydraulic engines, defigned for the pur- 

 pofe of elevating water j they are compofed of hollow 

 cylinders A B (Plate VII. fig. 3.) or E F (Plate VIII. 

 fig. i.) of an equal diameter throughout their whole 

 length, which is called the body of the pump, and in 



which 



