228 
Journal of Agricultural Research 
Vol. XXXI, No. 3 
to determine the size of pump needed and the speed at which it should 
be operated to give the most economical performance. 
It was for the purpose of providing data of this kind, of which very 
little has hitherto been published, mat the Division of Agricultural 
Engineering, Bureau of Public Roads, United States Department of 
Agriculture, conducted the tests which are reported here. The 
principal object was to determine the proper speed of pumps for vari¬ 
ous heads and capacities. In making the tests, a study of various 
types of impellers was not attempted, the aim being to obtain results 
which would conform with field installations. 
THE PUMPS TESTED 
The tests were made at the laboratory of the New Mexico Agri¬ 
cultural College, State College, N. Mex. 2 (fig. 1), under a cooperative 
agreement between the New Mexico Agricultural Experiment Station 
and the Division of Agricultural Engineering of the Bureau of Public 
Roads. 
By the courtesy of three manufacturers, seven deep-well turbine 
pumps were obtained for testing. Pumps Nos. 1, 2, and 3 were 
obtained from the American Well Works, Aurora, Ill. They were 
24-inch, 3-stage; 14-inch, 5-stage; and 12-inch, 7-stage, respectively. 
Pumps Nos. 4, 5, and 6, obtained from the Layne & Bowler Cor¬ 
poration of Los Angeles, were 24-inch, 2-stage; 17-inch, 4-stage; 
and 17-inch, 2-stage, respectively. Pump No. 7 was a 17-inch, 
4-stage pump obtained from the Byron-Jackson Co. of San Francisco. 
Each of these pumps was installed in- a 12-inch bored and cased 
well with a capacity of 2,000 gallons per minute. Power was fur¬ 
nished by a 40-horsepower variable-speed motor with controller. 
MODE OF PROCEDURE 
Before the tests were started an investigation was made of the 
constancy of the voltage, and a prony brake test (fig. 2) was run on 
the motor to develop data for an efficiency curve which would con- 
* Acknowledgment is due Dean W. Bloodgood, irrigation engineer, for his assistance in making pump 
tests, computation of data, and plotting original characteristic curves. 
