884 EXPERIMENT STATION RECORD. 



" The duty of water for the Porto Rico Irrigation Service, as defined by 

 law, is '4 acre-feet per acre per annum, the said standard to be applied on the 

 basis of fair average years.' Irrigation is carried on continuously throughout 

 the year. The crop is practically entirely sugar cane and it is planted during 

 both spring and fall months." 



From experiments from various sources and general conditions in Porto 

 Rico, a curve is given showing " that the value of water in percentage of yield 

 rapidly decreases as a maximum crop is approached, and unless water is 

 very cheap its use beyond that point will not be financially profitable. Up to 

 about 85 per cent its use is of maximum value, thence up to 100 per cent of 

 minimum value to the CTop. ... As the maximum tonnage is passed, the per- 

 centage of sucrose in the cane decreases more rapidly than the tonnage of 

 yield on account of the harmful effect of surplus water and oversaturation of 

 the soil. Also between 30 and 80 per cent yields an increase per annum of 1 in. 

 of beneficial water gives 1.8 per cent Increase in yield." 



Other climatic and hydrographic data are reported " to illustrate the danger 

 of using [such] data covering short periods of time as fair bases for technical 

 problems and the construction of expensive structures." 



The use of mud-ladened water in drilling wells, I. N. Knapp (Trans. Amcr. 

 Inst. Mining Enyin., 51 (1016), pp. 571-o86, fins. 2). — The object of this paper 

 " is to describe the mixing, testing, and use of mud-laden water for rotary 

 drilling in such a way as to make them helpful to the driller, the operator, or 

 the engineer in solving his own special drilling problems. The structures, 

 apparatus, and tools used are indicated in a general way. . . . 



" The information is the result of actual experience in drilling in Coastal 

 Plain formations. The materials encountered in the wells drilleil were uncon- 

 solidated sands, gravels, and clays, in which thin layers of sandstones, shell 

 conglomerates, and shales began to appear at about 1,200 ft. in depth." 



Irrigation in Netherlands East India (Xcthcrlamls East Indian Han Fran- 

 cisco Com., Dcpt. A(/r., Indus., and Com., Essay i\'o. 12 (1914), pp. 7.?, pis. 5, 

 figs. 10). — This pamphlet describes the climate, rainfall, and surface water sui> 

 plies of Java and the distribution and extent of the rice fields of Java and Ma- 

 doera, discusses the cultivation of crops needing irrigation, and sketches the his- 

 tory and development of irrigation in the Dutch East Indies. Brief descriptions 

 of some of the chief irrigation works are also included. Other topics dealt with 

 are drainage and fiood protection ; harmful influence of active volcanoes on 

 irrigation works; reservoirs for irrigation purposes; development of the water 

 management, cost of management and maintenance ; expenditure and staff for 

 irrigation purposes ; results obtained from irrigation works ; and irrigation in 

 the possessions beyond Java and Madoera. 



Surface water supply of north Pacific drainage basins, 1912, N. C. Gboveb, 

 F. F. Henshaw, G. C. Baldwin, and W. A. Lamb (U. S. Gcol. Survey, Water- 

 supply Palter 332 (1916), pp. XI+748, pis. 2). — ^This report combines the ma- 

 terial covered by Parts A-C, previously noted (E. S. R., 32, p. 587; 33, pp. 

 484, 880). 



Water powers of the Cascade Range. — III, Yakima River basin, G. L. 

 Paeker sind F. B. Stokey (U. S. GcoI. Surrey, ^yater-SuppIy Paper 369 (1916), 

 pp. 169, pis. 20, figs. 12). — This report, prepared in cooperation with the Wash- 

 ington Geological Survey, is based on data consisting of stream-flow records, 

 I'iver plans and profiles, reservoir surveys, and field reconnaissances of streams 

 in the Yakima lUxev basin, an area of about 5.970 square miles slightly south- 

 east of the geographic center of Washington, continuing previous work ( E. S. R., 

 24, p. 313; 29, p. 84). 



