OFFICE OF EXPEEIMENT STATIONS. 307 



The apicultural work has been considerably extended, and, through 

 the cooperation of the governor of the island, instruction in beekeep- 

 ing is given in the schools in conjunction with school-garden work. 

 The station has supplied nuclei, which are to be increased until every 

 school is provided with colonies of its own. 



The relations of the station with the various departments of the 

 island government are satisfactory. On the whole, the station enjoys 

 the confidence and good will of the naval authorities and the native 

 inhabitants of the island to an increasing extent. 



IRRIGATION INVESTIGATIONS. 



During the year the work of irrigation investigations continued 

 to be largely devoted to scientific and technical studies, the leading 

 subjects being the best practice in applying water to crops, as to 

 time of application, quantity applied, and methods of applying; the 

 measurement of irrigation water; the flow of water in canals and 

 pipes; pumping for irrigation; and the operation of irrigation dis- 

 tricts and mutual and cooperative canal companies. 



The investigation of use of water in irrigation, made during the 

 season of 1914, consisted in field and plat experiments to deter- 

 mine the effect of applying different quantities of water to crops, 

 tank experiments to get more accurate results where conditions were 

 largely under control, and soil-moisture determinations in the field 

 to ascertain what part of the moisture applied in irrigation re- 

 mained within the zone of plant roots and was therefore of use to 

 the plants. The results of all these investigations tended to show 

 that with the heavy irrigations usually given crops much of the 

 water is lost by deep percolation. This suggested that equally good 

 results might be obtained with the use of much less water if methods 

 of applying the water, the quantities used, and the time between ap- 

 plications could be adapted more carefully to the various types of 

 soil. Consequently the investigations of 1915 along this line have 

 dealt principally with the movements of soil moisture and the adapt- 

 ing of irrigation practice to soil conditions. It is believed that in 

 this line of adapting irrigation practice to soil conditions lie great 

 possibilities for both economy of water and increased crop returns. 



The experiments with measuring devices at the hydraulic labora- 

 tory at the Colorado agricultural college have been continued 

 throughout the year. Reports of these experiments containing dis- 

 charge curves and tables for various types of weirs have been pre- 

 pared for publication, and two new types of measuring devices have 

 been designed and calibrated. It is believed that these will be found 

 useful under conditions where weirs of the standard types can not 

 be used. At the New Mexico experiment station experiments with a 

 submerged orifice have been made and a report giving the results has 

 been approved for publication by that station. At the Davis farm 

 of the University of California all the measuring devices commonly 

 used in that State have been calibrated against standard weirs and the 

 results have been published by the university. Other devices not in 

 common use have also been tested at the Davis farm to determine 

 their value under California conditions. 



The investigations of the flow of water in canals and other con- 

 duits, begun in the previous year, have been continued. A bulletin 



