WATER PBESSURE

365

the tank top.    Water is then pumped into the tank until it reaches a
height of 8 feet in the stand pipe.   The pressure inside the tank ^vill

Fig  5
then be 64 X 8=512 Ibs. per square foot. When pumping up tanks and the
water overflows in the air pipes an excessive pressure is being exerted
on the inner sides of the tank and the pumps should be stopped.
Example.—The level of the water in the expansion trunk of a tanker
is 6 feet higher than the bottom of the summer tanks the area of which
is 60 ft. X20 ft., what is the upward thrust on the bottom of the summer
tanks which happen to be empty ?
UMe

Fig, 6.
64 Ibs.x6 ft.Xl200 sq. ft.-f-2240 lbs.=205*7 tons.
The question of water pressure is a serious one for a deep sea
diver as the atmospheric pressure within his suit and his body has to be