24 
BULLETIN 57, U. S. DEPARTMENT OF AGRICULTURE. 
Water weighs 62.5 pounds per cubic foot and there are 7.48 gallons 
in a cubic foot. Divide the number of gallons pumped per minute 
by 7.48 to get the cubic feet pumped per minute. Multiply the 
cubic feet by 62.5 pounds to get the weight of water pumped per 
minute. Multiply the weight by the total lift, which will give the 
foot-pounds of work per minute; 33,000 foot-pounds per minute 
equal 1 horsepower. Divide the foot-pounds per minute by 33,000 
and the result will be horsepower. The horsepower as computed 
from the quantity pumped per minute and the 
total lift should be doubled, as a pumping outfit 
usually has an efficiency of about 50 per cent. 
In general, from 1 to 3 horsepower is all that 
is required for ordinary farm pumping. In 
cases where water for the house only is wanted, 
J to | of a horsepower is sufficient. 
TYPES OF PUMPS. 
There are several types of pumps which may 
be used in farm pumping. The most common 
are the ordinary lift pumps which simply 
raise the water to the ground surface from a 
shallow well. For elevated tank systems and 
pneumatic tank systems the combination lift 
and force pump is necessary. If a special air 
pump or compressor is not employed it is 
necessary that a combination air and water 
pump be used for pneumatic tanks, especially 
in pumping from deep wells. 
There are many types of hand force pumps 
for shallow and deep well pumping which may 
be applied to either elevated tank or pneumatic 
tank systems. 
Figure 15, page 18, shows a deep-well wind- 
fig. 20.— Pumping jack for either mill pumping outfit applied to a pneumatic 
deep or shallow well pumping. tank system> an( J fi gure 13 . pa g e 16, shoWS a 
shallow well windmill pumping outfit supplying water to a tank on 
the windmill tower. Figure 20 is a pumping jack which may be 
connected with a deep or shallow well pumping outfit applied to 
either system. This jack may be operated by gas engine or electric 
motor. Figure 21 shows two other types of windmill force pumps, 
A for shallow wells, and B for deep wells. 
In obtaining information from the manufacturers of pumping 
equipment as to the particular equipment which will suit certain 
needs, the power required, etc., it is well to send data on the follow- 
ing: The source of water supply, whether a well, spring, or surface 
