HYDROSTATICS, &c. 



THE science of weighing fluids, or weighing 

 bodies in fluids. The doctrine of the equili- 

 brium and pressure of fluids. 



Hydraulics. 

 The science of conveying water through pipes. 



Pressure of Fluids. 



The general rule for estimating the pressure of 

 any fluid is, to multiply the height of the fluid by the 

 extent of the surface on which it stands, and the pro- 

 duct gives a mass which presses with the same weight 

 as the fluid standing on that surface, however shallow 

 it may be, provided a portion is supported at the 

 height by a tube. 



The pressure of any fluid on a horizontal or level 

 surface is found by multiplying the height or depth 

 of the fluid, by the extent of surface. Thus if the 

 surface be three feet by two, or six square feet, and 

 the height of the fluid three feet, the pressure is 

 equal to eighteen cubic or solid feet of fluid. If it 

 be water, a cubic foot of which weighs 62 J pounds, 

 or 1000 ounces, the pressure is equal to 1125 pounds. 



Pressure of Fresh Water. 



The pressure of fresh water is always about 13 

 pounds on every square inch at the depth of 30 feet, 



