RUEAL ENGINEERING. 287 



tion by spraying amounting to 130 mm. (5.1 in.), extending from April 1 to 

 June 30, plus 120 mm. of rain was accompanied by a decided increase in the 

 crop of winter rye. An irrigation of 180 mm. only slightly increased the yield 

 further. One hundred and ten mm. and 290 mm. of spray irrigation plus 403 

 mm. of rain water were accompanied by a decided but unprofitable increase in 

 the yield of hay on sandy soil. The root development was also decidedly in- 

 creased. 



The results with beans on a sandy soil using 12.5 mm. of irrigation were not 

 ■profitable, but the increase accompanying an irrigation of 165 mm. was quite 

 profitable. Negative results accompanied the irrigation of white and retl cab- 

 bage on sandy soil and of red beets on heavy soil. Tomatoes on sandy soil 

 burst and rotted badly on account of an abnormal rainy period, especially on 

 the irrigated plats. In spite of this the profit due to increase of crop accom- 

 panying Irrigation was marked. An excellent profit was obtained by the irriga- 

 tion of fi-uit bushes and trees on sandy soil using 70 mm. and 150 mm. of irriga- 

 tion plus 120 mm. of rain. Profitable results accomjJanying irrigation were ob- 

 tained with sugar beets on a heavy soil in only two out of four cases, but irri- 

 gation w&s quite profitable with carrots on this soil with 40 mm. and 50 mm. 

 of irrigation plus 400 mm. of rainfall from May 1 to September 30. An irriga- 

 tion of 110 mm. slightly increased this profit. 



The water economy of the soil, G. Richter (Jahresber. Kaiser Wilhelms 

 Inst. Landiv. Bronihcrg, WIS, pp. 43--'f5). — In studies of the influence of culti- 

 vation on the water economy of light sandy soil it was found that harrowing 

 five times immediately after rains was accompanied by a marl^ed increase in the 

 yield of corn. Irrigation increased the water content of both the surface soil 

 and subsoil of grass land, but the water content of the subsoil decreased with 

 the depth and with the amount of living and dead root matter. The water con- 

 tent of meadow and barley soils even when unirrigated was greater than that 

 of grass and rye land, indicating, it is thought, that rye and grass possess a 

 greater ability to utilize the water. Plowing and harrowing of the rye soil 

 after harvesting followed by fallowing increased the water content of the sur- 

 face soil about 2.1 i>er cent bj^ weight, but did not atfect that of the subsoil. 



Studies in water supply, A. C. Houston (London: Macumllan & Co., Ltd., 

 1913, pp. XII-\-203, pi. 1, flgs. 42).— The contents of this monograph have been 

 previously noted (E. S. R., 31, p. 416). 



River discharge, J. €. Hoyt and N. C. Grover {^ew York: John Wiley <& 

 Sons, 1914, 3. ed. rev. and enl., pp. XII +182, pis. 10, figs. 3S).— This is the third 

 edition of this book (E. S. R., 29, p. 487), and has been further expanded to pre- 

 sent the latest information on the subject. 



Surface water supply of the Yukon-Tanana region, Alaska, 1907 to 1912, O. 

 E. Ellsworth and R. AV. Davenport (V. S. Geol. Survey, Water-Sup ply Paper 3^2 

 (1915), pp. 343, pis. 13, flgs. 5). — This report gives a detailed summary of the 

 water-supply studies in the Yukon-Tanana region since 1907, these having been 

 discontinued indefinitely. The work of 1907 and 1908 has been previously 

 noted (E. S. R., 21, p. 309). 



The physical and climatic features of the region are first described, followed 

 by descriptions of stream basins and the results of measurements of flow 

 therein. It is stated, among other things, in conclusion that the stream flow in 

 the region is generally unfavorable foi" hydraulic development. " The condi- 

 tions of the Yukon-Tanana region are particularly unfavoraljle for the develop- 

 ment of water power. The combinations of low minimum run-off without nat- 

 ural storage or favorable means of developing artificial storage, of low and 

 uniform sti'eam grades, of short seasons, and of variable market make the use 

 of water power a last resort." 



3451°— No. 3—15 7 



