296 



THE IRRIGATION AGE. 



obtain in the practice of irrigation, the writer determined upon a 

 series of tests which should be carried out along lines of strictly eco- 

 nomic purpose, but controlled by the aid of such physical and chem- 

 ical observations as were previously shown to underlie any system of 

 rational irrigation 



The Hawaiian Experiment Station is located in the suburbs of Hon- 

 olulu and comprises five acres of land. In laying out the area into 

 divisions and plats special provisions was made for the use of irriga- 

 tion water. The water supply is that of the city municipality, and it 

 is laid on by iron pipes with very numerous faucet discharges. The 

 distribution is made by means of rubber hose, thus controlling the 

 delivery at any place or time. 



The topography of the field is favorable for irrigation; its surface 

 being relative level. 



The soil is exclusively derived from the decomposition of basaltic 

 lavas. There is a depth of 15 inches of tillable earth resting upon a 

 porous subsoil- an understratum which is composed of chips of lava 

 stone, scoria, and black sand. The total mass of soil is thus relatively 

 small, 1 acre to the depth of 15 inches weighing 4,368,825 pounds. 

 The constituents of the soil are shown in the following table: 



ANALYSIS OP SOILS AT HAWAIIAN EXPERIMENT STATION. 



Continued. 



