386 EXPEEIMENT STATION RECORD. 



trated and described, and considerable data are given to be used in pumping, 

 measuring, and distributing irrigation water. 



The rating of current meters, J. B. Bbown (Enffin. News, 10 {1913), No. 15, 

 pp. 712-714, figs. 4)- — This article describes the process of rating current meters 

 used by a water company selling Irrigation water by current meter measure- 

 ment (E. S. R., 28, p. 889). The rating station consists of a concrete lined 

 flume 175 ft. long over which a car driven by a variable speed motor is oper- 

 ated. Ten observations are taken with each meter at speeds approximating 

 ^, 1, IJ, and 3 ft. per second. The observations recorded are number of revo- 

 lutions of the meter, distance traveled, and time in seconds for each run. 

 Revolutions per second and the corresponding velocities in feet per second are 

 computed and rigorously adjusted, and from these results a rating curve is 

 platted. 



Sample observations, computations, and the resulting curve are given, with 

 formulas for computing and adjusting results.- 



Summary and report on the first subsoil blasting demonstrations in 

 Trinidad, 1913, H. Vincent (Proc. Agr. Soc. Trinidad and Tohago, 13 (1913), 

 No. 9, pp. 449-454). — Experiments were conducted in the blasting of water- 

 logged subsoils covering 11 districts of Trinidad, 8 of which possessed an ex- 

 tremely tenacious clay subsoil. About 15 acres altogether were blasted and 10 

 cases of dynamite cartridges were used. The summary of data given in tabu- 

 lar form shows that the depth of charge varied from 1 ft. 6 in. to 4 ft. and the 

 spacing of holes from 8 to 24 ft. 



From the results of the experiments the advantages of blasting water-logged 

 lands are summarized, including the improved aeration of the soil, the decreas- 

 ing of surface wash, the better incorporation of the plant food in manures, an 

 increased solvent action from rain water, and an improved porosity in stiff 

 clays, with consequent greater root depth and drought resistance. 



Object-lesson and experimental roads, and bridge construction, 1912-13 

 (U. S. Dept. Agr. Bui. 53, pp. 34)- — ^This bulletin describes in detail the construc- 

 tion of object-lesson roads during the past fiscal year, including one each of 

 bituminous-concrete, bituminous-macadam, gravel-macadam, brick-cinder, and 

 sand-gumbo roads, 3 shell roads, 4 gravel roads, 7 macadam roads, 9 earth 

 roads, and 14 sand-clay roads. The total area of object-lesson roads showed 

 an increase from 79,203 sq. yds. In 1905 to 488,331 sq. yds. in 1913. 



In addition reports are given of bridge work and inspection of object-lesson 

 roads, a report of work on the Memphis to Bristol Highway, and a brief account 

 of experimental work for the year, which is to be reported in detail later. 



Concrete roads and pavements, E. S. Hanson (Chicago, 1913, pp. 227, figs. 

 29). — It is the purpose of this book not only to stimulate the construction of 

 concrete roadways but also to furnish road makers specific data from the ex- 

 perience of others. The matter is presented under the following chapters: 

 Concrete as a road material ; the construction of concrete roadways ; the roads 

 of Wayne County, Michigan ; cost of concrete roads in Illinois ; other examples 

 of concrete roads; some data on city pavements; reinforced concrete pave- 

 ments; concrete in combination with other materials; patented concrete pave- 

 ments; the theory and practice of joints; some tests of concrete as a roadway 

 material ; bridges and culverts ; sidewalks, curbs, and gutters. 



Specifications for concrete roads and pavements from various sources are 

 appended. 



Concrete pavement troubles (Cement World, 7 (1918), No. 7, pp. 46-48, figs. 

 3). — Data and photographs are given relating to the causes operative in 

 numerous examples of failure observed in concrete roads and pavements, 

 covering a wide range of local conditions. Failures are attributed chiefly to 



