1918] RURAL ENGINEERING. 189 



sodium-sulphochloramid) as a disinfectant for treating drinking water are 

 reported. 



It was found that 0.04 gm. of chloramin T will completely sterilize 1 liter 

 of any water in 10 hours even when 10,000 organisms per cubic centimeter are 

 present. " The water so treated is entirely devoid of any unpleasant taste, 

 and will remain sterile for at least four days. There is evidence to show that 

 its activity is markedly increased by the presence of organic matter in solu- 

 tion in the water, in fact organic matter is essential for the compound to exert 

 its action as a disinfectant. Chloramin T possesses many advantages over 

 bleaching powder as a chemical reagent for sterilizing water, more particularly 

 its definite and unalterable comix>sition, its stability in solution, nontoxicity, 

 absence of corrosive action, and nonproduction of an unpleasant taste in the 

 treated water. All the results tend to demonstrate that we have in certain 

 of the chloramins the ideal reagent for sterilizing water on a large scale." 



Standard road sections {Helena, Mont.: Mont. State Highway Com. [19171, 

 pp. 12, figs. iO).— Diagrammatic illustrations of standard road sections used by 

 the Montana State Highway Commission are given. 



Standard plans, box culverts, slab and girder bridges, 1916 {Des Moines, 

 Iowa: loica State Hightvay Com., 1916, pp. 27, figs. 26). — This book contains a 

 complete set of standard plans for concrete highway culverts and slab and deck 

 g:rder bridges issued for 1916 by the Iowa State Highway Commission. 



" The box culvert designs ... are prepared for both straight and flaring 

 wing walls for span lengths ranging from 2 to 12 ft. The standard slab 

 designs . . . are prepared for lengths of span from 14 to 24 ft. The deck 

 girder designs . . . range in span lengths from 24 to 40 ft." 



Highway bridges, 1917, G. Hogarth (Ann. Rpt. Dept. Pub. Highways On- 

 tario, 1916, App., pp. 26, figs. 25). — This is an appendix to the annual report of 

 the Department of Public Highways of Ontario and deals with the construction 

 of highway bridges in the Province. It is in part explanatory of the specifica- 

 tions for steel and concrete bridges issued by the department and also com- 

 plementary to the series of general plans issued for steel and concrete bridges. 



Tests of concrete slabs to determine the effect of removing excess water 

 used in mixing, A. N. Johnson (Good Roads, n. ser., 14 {1917), No. S, pp. SI, 

 32, fig. 1). — Experiments with 12 concrete slabs 2.5 ft. wide, 5.5 ft. long, and 

 5 in. thick to determine the influence on strength of removing the excess water 

 by rolling, as is being done in concrete road work, are reported. A 1 : 2 : 3 mix- 

 ture was used, and the consistencies used were a dry and a wet consistency 

 finished with a wood float and a wet consistency finished with a roller. 



It was found that " those slabs finished with the roller developed a very 

 considerable increase in strength over the slabs merely hand-finished. The four 

 slabs of wet consistency that were finished by hand have an average modulus 

 of rupture of 308 lbs. per square inch, while the four slabs finished with the 

 roller have an average modulus rupture of 369 lbs. per square inch, or an increase 

 of almost 20 per cent. . . . The slabs that were made of a stiffer mixture, indi- 

 cated in the table as medium consistency, giving an average modulus of 340 

 lbs. per square inch, are stronger than those of the wet consistency, finished in 

 the same manner ; but the wet-consistency slabs finished with the roller are 

 stronger than those of the medium consistency, showing an increase of nearly 

 10 per cent. 



" The results seem to indicate clearly the value to be gained by the u>;e of 

 the roller to finish a concrete road; that it is possible by proper manipulation of 

 concrete to secure increased strength and density of a character most desirable 

 for a concrete road surface; and that such surplus water as may be required 



