EUEAL ENGINEERING. 287 



8; 8, pp. 224-226, figs. 7; 9, pp. 251,-256, fiys. 6; 10, pp. 281,-286, figs. J,; 11, pp. 

 S13-315, figs. 5; 12, pp. 338-31,0, figs. 8).— The substance of this article has been 

 previously noted from another source (E. S. R., 30, p. 690). 



Drainability of Emscher tank sludge, W. L. Stevenson {Municipal Jour., 

 39 {1915), No. 12, pp. J,27, J,28, figs. ^).— The author states that the essential 

 properties of sludge disposed of on land are odor, volume, and drainability and 

 reports the results of experiments to determine a simple test for the last. Com- 

 posite samples of each batch of sludg;e placed on the drying beds of a sewage- 

 disposal worlis were submitted to the two following procedures : 



A portion amounting to 700 cc. is placed in a 1,000-cc. measuring cylinder, 

 and the amount of clear water separated at the bottom is observed and 

 recorded at hourly intervals. This is continued until the sludge begins to 

 settle down into the water again. Another 700-cc. portion is placed in a 

 vertical piece of glass tubing of the same internal diameter as the measuring 

 cylinder. Over the lower end of the tube is secured a piece of wire screen 

 which supports a i-in. layer of small pebbles, a ^-in. layer of clean Jersey 

 gravel, and a 2-in. layer of fine sand. The tube is held in a retort stand over a 

 funnel resting in a measuring cylinder to collect the water draining out of the 

 sludge, and the accumulated amount of water is read at hourly intervals until 

 the sludge ceases to drain. The results are graphically reported, together with 

 the usual analysis. 



The results indicate that the factors which should be combined to represent 

 the drainability of a sludge are (1) the rate of drainage, represented by the 

 slope of the first part of the curve, (2) the ratio between the amount of water 

 ■drained from a liter of sludge and the amount of moisture therein as deter- 

 mined by the usual evaporation method, and (3) the time required for the water 

 to begin to drain out. Good sludge will be indicated by (1) having a steep 

 slope, (2) showing a large number for the ratio, and (3) showing a short time; 

 poor sludge the reverse. 



Third international road congress {Internat. Assoc. Road Cong., III. Cong. 

 [London], 1913, Rpts., pp. 3335, pis. 56, figs. 373).— The proceedings of this con- 

 gress are reported in detail and consist mainly of 123 reports on various phases 

 of road design, construction, maintenance, cost, and administration, and on 

 laboratoi-y work related thereto. 



Gas, gasoline, and oil engines, G. D. Hiscox, revised by V. W. Page (New 

 York: The Norman 11'. Henley Publishing Co., 1914, 21. ed., rev. and enl., pp. 

 6J,0, pis. 2, figs. 433). — In this, the twenty-first edition of this book, it has been 

 attempted to include striking examples of all recent developments in the field 

 of internal combustion engineering. The design, construction, and operation of 

 all forms of gas, gasoline, kerosene, and crude oil engines, including particularly 

 farm and gas tractor motors, ai*e dealt with. 



The book contains chapters on the subjects usually discussed in such a 

 treatise, including the following of particular agricultural engineering interest : 

 Cylinder capacity of stationary gas and gasoline engines; types and details of 

 stationary explosion motors ; kerosene, distillate, and crude oil motors ; and 

 farm motors — gas tractor power plants — electric-lighting plants. 



The superiority of electrical power for agricultural operations, W. Beck 

 (Ztsclir. Landic. Kammer Schlesicn, 19 {1915), Nos. 20, pp. 596-598; 21, p. 

 621). — A brief statement of the amount of electrical power required for oper- 

 ating different agricultural machines is given. 



Coatings for cement vats {California Sla. Rpt. 1915, p. 31). — "Laboratory 

 tests by the division of viticulture and enology indicate that coating of mixed 

 paraffin and beeswax, paraffin, rosin, and beeswax, tasteles fossil asphalt, such 



