1920] RURAL ENGINEERING. 279 



edition of this standard handbook. A new section of special Importance on 

 irrigation and drainage has been added. 



Report on irrigation surveys and inspections, 1918-19, E. F. Dkake 

 and F. H. Peteks {Dcpt. Int. Canada, Reclam. Serv., Rpt. Irrig. Surveys and 

 Insp., 191S-19, pp. 67, pis. 3, fig. i).— This includes the report of the director of 

 the Canadian Reclamation Service and the report of the Commissioner of Irri- 

 gation of Canada, including data on large irrigation projects and duty of 

 water for 191S. Considerable data on duty of water are summarized, it being 

 shown that the average depth for wheat, oats, and barley is 1.7 ft. and for 

 alfalfa 2.1S ft. 



Irrigation practices, A. O. Kay {Fla. Univ. E.vt. Bui. 24 {1920), pp. J,5- 

 ^S). — Subsurface, surface, and overhead irrigation are briefly discussed. 



The duty of water in the Pacific Xorthwest, J. C. Stevens (I'roc. Ainer. 

 Soc. Civ. Engin., JfG {1920), No. S, pp. JiGl-.'/SO, fig. J).— It is the object of this 

 paper to suggest lines along which future research in duty of water should be 

 conducted. The process is illustrated by an actual example and the correct- 

 ness of the determination substantiated by, results actually secux'ed on projects 

 where crop statistics and other data are available. Brieflly stated, the deter- 

 mination of the duty of water consists in first fixing the average percentage of 

 soil mixture tliat should be maintained for the particular soil and crops, and 

 then finding a quantity of irrigation water that, with the precipitation and the 

 unavoidable losses, will maintain that amount of soil moisture. This method 

 makes the free soil moisture in the root zone of the plants the index of plaat 

 sufficiency. 



Well waters for irrigation, C. Vallejo {Rev. Soc. Rural Cdrdoha [Argcn- 

 Hna], 19 {1919), No. 360, pp. 4902-^907).— Features of irrigation by well water 

 in Argentina are reviewed. It is noted that in irrigated regions the well waters 

 generally contained salt concentrations of about 270 parts per 100,000. In every 

 case considerable sodium carbonate was present. 



Water supply by means of cisterns, F. Nikolai {Arch. Uyg., 86 {1917), No. 

 6-8, pp. 318-337, figs. .'/). — Laboratory and field experiments are reported which 

 show that cistern water can be quickly, easily, and safely disinfected and 

 rendered potable when treated with bleaching powder at the rate of 10 mg. per 

 liter and after some hours neutralized with sodium hyposulphite. 



A suggestion on a method for purifying water and its significance in 

 laboratory practice and sanitary water analysis, G. A. Linhart {Berkeley, 

 Cal.: [Leafiet], 1919, pp. [2]). — It was found that when alkali water was frozen 

 into rectangular blocks of 2.50 lbs. the ice was perfectly clear except for a slab 

 in the center varying from 6 to 8 per cent of the total weight of the cake. Tlie 

 clear ice in all cases analyzed to practically 100 per cent pure, all of the dis- 

 solved substances, as well as the suspended matter, having collected in the 

 center slab. While this method of purifying water may prove, from a com- 

 mercial standpoint, prohibitive for irrigation purposes, it is considered to offer 

 a simple and accurate method of concentrating extremely dilute solutions for 

 chemical analyses, for example, of water extracts of soils. 



Tlie action of water on lead, J. F. Liverseege and A. W. Knapp {Jour. 

 Soc. Chem. Indus., 39 {1920), No. 3, pp. 27T, 32T, figs. 2).— Experiments with a 

 faintly alkaline natural water are reported with particular reference to the 

 so-called erosion test, which is an estimation of the action of water on com- 

 pletely immersed sheet lead. The test is performed with bright lead in water 

 with free access to air. 



It is concluded that erosion is due to the action of oxygen in the presence of 

 water, and that such variations as occur naturally in the percentage of oxygen 

 present in the water produce no appreciable effect on the erosion. 



