EUEAL ENGINEEEING. 487 



Kopjes irrigation scheme, Orange Free State, J. Muller (.Agr. Jour. Union 

 So. Africa. 5 (1913), No. Jf, pp. 5Ji5-553, fig. 1). — Analyses were made of samples 

 of soil talien from lands included in the Kopjes Irrigation Project for the pur- 

 pose of ascertaining the existence of injurious quantities of alkali salts at the 

 surface of irrigable areas or in sufBcient quantities in the substrata of such 

 areas as to render the surface alkaline after repeated irrigation. The results 

 of these analyses forcibly emphasize the necessity of improving the soil tex- 

 ture by efficient underdrainage. cultivation, and the use of lime. 



Analyses of the water supplies available for irrigation indicate that they are 

 suitable for the purpose, provided the soil drainage is reasonably good. 



River discharge, J. C. Hoyt and N. C. Groveb {Neio York and London, 2. ed., 

 rev. and cnl., 1912, pp. XII+173, pis. 8, figs. 38).— This, the second edition of 

 this book (E. S. R., 19, p. 512), is a revision in which are noted the material 

 advances which have been made in the development of methods and instru- 

 ments for stream gaging. The authors have attempted to incorporate the latest 

 practice in stream gaging work and have added considerable hydrographic and 

 actual stream flow data. 



Superelevation at bends on roads, R. Ryves (Surveyor, Jf3 (1913), No. llli, 

 pp. 791i-796, figs. 4).— From the results of several studies a comparison is made 

 of the limits of safe*and useful employment of superelevation at bends on roads 

 and on railroad curves. It is concluded that the principle of superelevation as 

 applied to railroad curves can be safely applied to road beds to only a very 

 limited degree and that the best policy is to allow only such superelevation as 

 is correct up to some low and definitely fixed speed limit. 



General specifications for roads and bridges, C. Hill ([ColumMa, Mo.]: 

 State Highway Engin., [1911], pp. 51). — This pamphlet refers to the state road 

 laws of Missouri and gives general specifications for the construction of rock, 

 gravel, telford, and sand-clay roads ; steel, concrete, and masonry highway 

 bridges; bituminous binders; surface and penetration road, oils; road tar; 

 and culvert pipe. 



How Reclamation Service makes concrete pipe (Cement Era, 11 (1913), 

 No. 6, pp. 5S, 59, figs. 5). — This article describes the methods employed by the 

 Reclamation Service in the construction of plain and reenforced concrete pipe 

 for conveying irrigation water and reports the results of service tests on sev- 

 eral lines of various sizes and types of construction. 



Unreenforced concrete pipe of small sizes manufactured by the dry-mixed 

 process has been found to be generally unsatisfactory for pressure pipe. The 

 maximum allowable heads under which these pipes may be used under the most 

 favorable circumstances are given as 20 ft. for 6 in. pipe, 15 ft. for 8 in. pipe, 

 12 ft. for 10 in. pipe, and 10 ft. for 12 in. pipe, and it is stated that unreenforced 

 pipes of larger diameters than 12 in. can not be safely used under pressure. A 

 thickness of shell of less than 2 in., even for the smallest pipe, has been found 

 to be impracticable. Several finished reenforced pipe lines varying from 8 to 

 54 in. in diameter and under maximum heads varying from 22 to 115 ft. were 

 tested under full pressure with satisfactory results. 



Effect of moisture on the strength of concrete: An explanation of con- 

 crete drain tile failures (Cement and Engin. Neips, 25 (1913), No. 6, p. 177). — 

 Experiments conducted by S. M. Woodward and F. C. Young indicate that 1 : 3 

 Portland cement mortar cured in air under conditions similar to those com- 

 monly obtained in the manufacture of cement drain tile was weakened from 

 40 to 50 per cent by being soaked with water, the weakening effect taking place 

 as soon as the specimens were saturated. This is considered a physical and not 

 8297°— No. 5—13 7 



