1917] BUEAL ENGINEERINO. 695 



of calcium sulphate in the presence of ammonium carbonate, giving calcium 

 carbonate and araonium sulphate. The calcium carbonate settles out and the 

 liquid containing ammonium sulphate is concentrated until the crystals sepa- 

 rate. The precipitated calcium carbonate contains much organic matter rich in 

 nitrogen. The solid matter from the decantation process is filter pres.sed and 

 then autoclaved for 15 minutes at 140 to 150° C. The vapors from the auto- 

 clave are condensed to recover the ammonia salts in them, and the solids re- 

 maining in the autoclave are dried for fertilizer. This process, it is .stated, re- 

 quires only a simple apparatus and cheap chemicals and is considered to be 

 adapted for use on farms and in rural communities of France, as well as in 

 larger towns, for the production of fertilizer from sewage. 



Rural sanitation {Cal. Bd. Health Mo. Bui, 12 (1916), No. 2, pp. 7^-81; abs. 

 in Chem. Abs., 10 (1916), No. 21, p. 2780).— This article outlines the public 

 health methods of the California State Board of Health and describes common 

 unhealthful conditions, including sewage entering streams, contaminated wells 

 and water supplies, carelessness in producing and handling milk, manure piles, 

 lly and mosquito breeding places, and insanitary privies. A form of notice to 

 abate nuisances issued by the board is included. 



Fifth annual report of the county highway commissioner of Milwaukee 

 County, "Wis., 1916, H. J. Kuelling (Ann. Rpt. Co. Highicay Comr., Milicaukee 

 Co., Wis., 5 (1916), pp. 9S, figs. 28). — This is a statement of the work and ex- 

 penditures of the office of the highway commissioner of Milwaukee County, 

 Wis., on highway construction, maintenance, and repair for 1916. 



Boad problems in the Ozarks, E. G. Harris (Bui. School Mines and Metal- 

 lurg., Univ. Missouri, 9 (1917), No. 1, pp. 2S, figs. 6). — This bulletin is a discus- 

 sion of the road problems encountered in the average sparsely settled, rugged 

 portion of the Ozark uplift, embracing about one-fourth of the area of Missouri. 

 It is stated that in this region the present bad location of many of the roads 

 constitutes the chief reason why improvement is impossible or possible only at 

 great and continuous expense. 



A list of references, compiled by H. L. Wheeler, on the construction and 

 maintenance of rural roads is included. 



Report of the fourth annual road drag competition, J. Kuehne and H. W. 

 Hettle (Saskatchewan Highway Comrs., Rpt. Road Drag Covipet., 4 (1916), 

 pp. 82, figs. 8). — An outline is given of the procedure and results of a road 

 dragging competition in the Province of Saskatchewan lasting through the 

 summer of 1916. 



Methods of determining the road making qualities of deposits of stone and 

 gravel, L. Reineckb (Oood Roads, 51 (1917), No. 20, pp. 293-297, figs. 9).— This 

 is an outline of the methods used by the department of mines of Canada in 

 arriving at the relative values of deposits of stone and gravel available for road 

 construction. 



" In order to determine the road making values of the rocks in a certain dis- 

 trict, they are first divided into formations and then into rock tyi)es. Their 

 average values and the variation in strength and cementing value of each type 

 are obtained by laboratory tests on a number of samples, and the results thus 

 obtained are compared with actual service tests in the roads wherever possible. 

 Laboratory studies with the microscope and by chemical analyses are then 

 undertaken to discover the cause of such variations in order to furnish data 

 which will enable the field man to distinguish a good stone from a poor one in 

 the outcrop. 



" With a working kaowledge of the strength of the bedrock in a district, an 

 attempt is made to devise a classification of the kinds of bowlders in the field 



