1918] 



RURAL ENGINEERING. 



289 



water contained in aluminum bottles. " One point of advantage possessed by 

 the present disinfectant over most hiT^ochlorite preparations is the fact that 

 the active chlorin is less rapidly used up, so that the process of disinfection 

 continues for a longer period." 



Information on the preparation, properties, and cost of the disinfectant are 

 also given, " It is safe to say that the tablets oould be sold at such a price that 

 100 gal. of water could be sterilized at a cost of one penny." 



Experimental roads in the vicinity of Washington, D. C, B. A. Anderton 

 and J. T. Pauls (17. S. Dept. Agr., Office Sec. Circ. 77 (1917), pp. S).— This cir- 

 cular summarizes data on methods of construction, maintenance, and up-to- 

 date cost records on experimental sections of surface treated macadam and 

 gravel, bituminous macadam, bituminous concrete, cement concrete, and brick 

 road in and near Washington, D. C. Traffic census data on most of the experi- 

 mental sections are also given. 



Massacliusetts Hig'hway Commission curve tables, compiled by A. M. Lovis 

 {New York: John Wiley d Sons, Inc., 1917, pp. 47, figs. 2).— Tables furnished 

 by the Massachusetts Highway Commission for externals, radii, arcs for tan- 

 gents of 100 ft., deflections for arcs of 100 ft., and skew distances for widths 

 of 2.5 ft. are given. 



Report of [Illinois] State Highway Commission, 1915-16 (III. Highway 

 Dept. Rpt., 1915-16, pp. 59, figs. 16). — This is a review of the work of the Illi- 

 nois State Highway Commission for 1915 and 1916. 



General specifications for materials {Ohio Highicay Dept., Specifica., No. S 

 (1915), pp. 77, figs. 9). — General specifications for road-building materials 

 issued by the Ohio Highway Department are given. 



Material specifications (Ohio Highioay Dept., Specifica., No. 4 (1915), pp. 77, 

 figs. 9). — Specifications issued by the Ohio Highway Department for Portland 

 cement, block, paving brick, stone and slag, gravel and sand, nonbituminous 

 and bituminous binders and materials, timber, linseed oil and paint, steel 

 and iron, and pipe are given. An appendix outlines methods of testing these 

 materials. 



The influence of total width on the effective width of reinforced concrete 

 slabs subjected to central concentrated loading, A. T. Goldbeck (Proc. Amer. 

 Concrete Inst., 13 (1917), pp. 78-88, figs. 13).— Tests conducted by the Oflice of 

 Public Roads and Rural Engineering of the U. S. Department of Agriculture 

 are reported to show how the effective width of a reinforced concrete slab 

 depends on the total width of the slab when it is supported at two ends only 

 and is subjected to a central concentrated load. • 



It was found that " as the width of slab increases the ratio of effective width 

 to span length shows considerable variation. This variation, however, is rep- 

 resentative of what might be expected in actual structures, and apparently 

 does not follow any law so far as thickness is concerned." The relation is 

 expressed in the following table: 



Relation of total width to effective ividth. 



