1918] RURAL ENGINEERIN-G. 389 



the'refore, from the results of these experiments that, although it has been 

 proved feasible to reclaim water-logged land by means of tile drains, it would 

 not be practicable to locate wells and pumping plants similar to the one de- 

 scribed . . . close enough together to lower the water table over any consider- 

 able area or develop enough water for practical farm irrigation without storage. 



" It is doubtful if the results of this experiment would have been materially 

 different had it been located on the more poorly drained areas. " 



Farm drainage in Virginia, C. E. Seitz (Va. Poly tech. Inst. Ext. Bui. 15 

 (1917), pp. 35, pi. 1, figs. 18). — This bulletin gives general but practical infor- 

 mation on the planning and construction of tile drains and drainage systems, 

 with special reference to Virginia conditions. 



Irrigation works constructed by the United States Government, A. P. 

 Davis {Neio York: John Wiley d Sons, 1917, pp. XVI +413, pi. 1, figs. 128). — 

 It is the object of this work to give engineering descriptions of the U. S. Recla- 

 mation Service works together with illustrations. Chapters are included on the 

 Salt River, Yuma, Orland, Grand Valley, Uncompahgre, Boise, Minidoka, Hunt- 

 ley, Lower Yellowstone, North Platte, Truckee-Carson, Carlsbad, Hondo, Rio 

 Grande, Umatilla, Klamath, Belle Fourche, Strawberry Valley, Okanogan, 

 Yakima, and Shoshone projects. 



Reservoir capacity for small pumping plants, S. T. Harding (Jour. Elec- 

 trinty, 39 (1917), No. If, pp. 170-172, figs. 2).— Curves of data are given on 

 capacity of reservoirs required to maintain rates of discharge varying from 100 

 to 1,000 gal. per minute for periods varying from 6 to 96 hours, and also curves 

 giving data on discharge of reservoir outlets for pipe sizes varying from 6 to 

 24 in. and head losses through outlets varying in size from to 18 in. 



Longevity of Bacillus coli in water, F. L. Rector and H. J. Dattbe {Abs. 

 Bact., 1 {1917), No. 1, p. 57).— Sterile 1-liter bottles were filled with distilled 

 water, tap water, and a bottled water and tested for B. coli with negative 

 results. Each bottle was then inoculated \vith 0.5 cc. of a 24-hour broth culture 

 of B. coli, plates being poured immediately and daily thereafter until negative 

 results were obtained. Litmus lactose agar plates were used. 



One day after inoculation there was a marked increase in the number of 

 B. coli, but subsequent examinations showed a gradual and regular decrease 

 which resulted in the final disappearance of the organism from the bottled 

 water in 25 days and from the tap water and the distilled water in 48 day^. 

 By cultivating in dextrose liver broth the organism was found to be present 

 in 50 cc. quantities in the bottled water until the thirty-sixth day, in the dis- 

 tilled water until the fifty-seventh day, and in the tap water until the sixty- 

 fourth day. 



Mechanical grading of concrete sand, O. R. Smith {Concrete [Detroit, 

 Mich.], 11 {1917), No. S, pp. 76, 77, figs. 5).— Tests are reported from which it 

 was concluded that " the most dense and strongest mortar for concrete work 

 is obtained if the sand has the following granulometric composition : " One- 

 fourth in. sieve, residue none ; No. 10 sieve, residue 60 per cent ; No. 20 sieve, 

 80 : No. 30 sieve, 85 ; No. 50 sieve, 90 ; and No. 100 sieve, from 95 to 98 per cent. 



Motor gasoline: Properties, laboratory methods of testing, and practical 

 specifications, E. W. Dean {U. S. Dept. Int.. Bur. Mines Tech. Paper 166 

 {1917), pp. 23, pi. 1; abs. in West. Engin., 8 {1917), No. 8, pp. 316-319, fig. 1).— 

 This pamphlet enumerates the desirable properties of gasoline and discusses 

 types of gasoline marketed and the relative value of various tests used. 



"Specific gravity in itself is of very slight significance in determining the 

 properties of gasoline. It may serve as an index of other properties, particularly 

 volatility, if knowledge is at hand regarding the source and method of produc- 

 tion of a gasoline. The determination of gravity has been and probably always 



