784 EXPERIMENT STATION RECORD. 



satisfactory. As regards disUiuce apart of laterals it is concluded that 6 rods 

 is about the maximum width for the level prairie. The proper depth on the 

 prairie seems to be around 2i to 2f ft. on the average, although the actual 

 depth varies from 2 to 3^ ft. 



Drainage problems in the Ganges delta, C. Addams- Williams (Calcutta^ 

 1913, pp. 35, pis. 19). — This book comprises a series of six lectures in which it 

 is proposed to illustrate the practical application of mathematical principles 

 in the design of the drainage works for delta lands. TTie discussion is con- 

 fined to actual problems encountered by the author in the Ganges delta near 

 Calcutta. The formation of the Ganges delta and the reclamation in the tidal 

 portions of the delta are discussed in some detail, followed by a discussion of 

 the practical design of the necessary drainage works. Maps and detailed draw- 

 ings of drainage works and specific structures are included. 



Some interesting experiments in hydraulics (Dom. Engin., 68 (1914), No. 

 2, p. 33, figs. 2). — Experimental data are given in tabular form showing the 

 actual quantity of water which bibbs of sizes from i in. to li in. will discharge. 



A proportional-flow weir. E. W. Rettgeb {Engin. News, 11 (191^), No. 26, 

 pp. 1409, 1410, figs. 2). — By means of mathematical analysis the author points 

 out that a weir who.se width at any point is inversely proportional to the square 

 root of the height of that point above the crest will have a theoretical discharge 

 exactly proportional to the head. By means of further mathematical analysis 

 he outlines a process for slightly modifying the theoretical shape of such a weir 

 so that the coefiicient of discharge will be constant for different heads. 



Modern pumping machinery, R. W. Allen (Sci. Amer. Sup., 78 {1914), No. 

 2009, pp. S-11, figs. 10). — The author deals chiefly with the mechanism of 

 pumping outfits as used for the drainage of the fens in England, which employ 

 vertical steam and horizontal oil engines driving horizontal spindle centrifugal 

 pumps. The description is confined to outfits representing some of the more 

 recent works in the district. Diagrammatic and other illustrations of important 

 features are given. 



Some tests on pipe reinforcing {Cement Era, 12 {1914), No. 7, pp. 44^ 45, 

 figs. 8). — Tests are reported on 6-in. sections of concrete pipe 22 in. in diameter 

 find 2.2 in. thick, reinforced with 2 circular bands of No. 7 bright wire placed 

 3 in. apart on centers, thus bringing them 11 in. from the outside edges. Each 

 band consisted of an inner and outer hoop, the inner hoop being placed f in. 

 from the inner wall and the outer i in. from the outer wall. The two hoops were 

 fastened together by (1) 6 radial ties, (2) 12 radial ties, (3) 6 radial ties and 

 6 tangential ties, and (4) 6 radial ties and ties in truss form. 



The average load at failure of four unreinforced specimens was 328 lbs. The 

 respective average loads at first crack for four specimens with each type of re- 

 inforcing were 465, 577, 835, and 1,047 lbs. ; and at failure 1,413, 1.490, 1,645, 

 and 1,770 lbs., thus showing the truss tied reinforcing to be much the strongest 

 type. 



The use of paint films as protective coatings for concrete, E. E. Wabe and 

 S. M. SCHOTT {Concrete-Cement Age, 4 {1914), No. 4, pp. 177-181, figs. 5).— 

 This paper discusses the basic principles of successfully coating concrete sur- 

 faces and reports investigations on the relative merits of various concrete coat- 

 ing materials. The materials were applied to the surfaces of concrete and stucco 

 panels and given an exposure test extending over about two years. To indicate 

 the leaching out of lime, one-half the surface of each panel was painted after 

 one year's exposure with a green paint, the pigment in which was a mixture 

 of chrome yellow and Prussian blue. Conclusions from the test are as follows : 



•'Assuming water to be an Important agent in the disintegration of concrete 

 and stucco, there is a necessity for a system of waterproofing that will prevent 



