1917] RURAL ENGINEERING. 591 



the 20,000 tons of garbage treated annually at the reduction works a total 

 of 96,000 gal. of alcohol, giving a profit of 42 cts. per gallon at war-time prices 

 or 30.5 cts. under normal conditions. A year's garbage, the tests indicate, 

 would yield as much alcohol as could be produced from 33,600 bu. of shelled corn, 

 39,529 bu. of wheat, or 110,344 bu. of potatoes. . . , 



" The process consists of extracting grease from garbage by cooking with 

 sulphuric acid and steam, thereby converting the starch and allied products to 

 dextrose, separating the grease from the tank liquor, neutralizing the acid 

 sufficiently to allow fermentation, fermenting the liquor with yeast, thereby 

 converting the dextrose to alcohol, and then recovering the alcohol by dis- 

 tillation." 



Agricultural practice, T. H. Lougheb {Estac. Expt. Agron. Cuba Bol. 31 

 {1916), pp. 85, pis. 30). — This bulletin deals mainly with the types of machinery 

 best adapted to Cuban agriculture and discusses soils and crops in general. 



The necessity of mechanical cultivation of soil, G. H6bon (Prog. Agr. et 

 Vit. {Ed. I'Est-Centre), 37 {1916), No. 29, pp. 61-69).— This is a brief com- 

 parison of animal with motor power, made on the basis of net expense of 

 cultivating a hectare of soil for one year. 



Public tests of motor cultivation, J. H. Soubisseau {Prog. Agr. et Vit. {Ed. 

 I'Est-Centre), 37 {1916), Nos. 30, pp. 82-93; 32, pp. 133-138; 33, pp. 160-166; 

 34, pp. 178-180; 35, pp. 205-212, figs. 12).— Tests of a number of motor plowing 

 and cultivating outfits are reported and discussed. The purpose was to deter- 

 mine some of the factors in the selection of motor-drawn tillage machines and 

 the cost of different motor tillage operations under French conditions. 



Homemade silos, F. M. Hillaian {Mont. Col. Agr. Ext. Serv. [Pub.] 

 21 {1917), pp. 31, figs. 23). — This circular describes the construction of differ- 

 ent types of silos under Montana conditions, special attention being given to 

 the less expensive types such as the pit silo. 



How to build the wooden-hoop silo, R. U. Blasingame {Ala. Polytech. Inst. 

 Ext. Serv. Circ. 9 {1917), pp. 6-12, pis. 4, flgs. 2).— This circular describes the 

 construction and gives bills of materials and costs for several sizes of wooden- 

 hoop silo. 



The Tennessee wood-hoop silo. — How to build it, C. A. Hutton {Col. Agr. 

 Univ. Tenn., Ext. Div. Pub. 26 {1917), pp. 19, flgs. i5).— This circular describes 

 the construction of wooden-hoop silos under Tennessee conditions. 



A dairy fann plant, I. D. Charlton {Washington Sta., West. Wash. Sta. Mo. 

 Bui., 5 {1917), No. 3, pp. 35-39, figs. 4).— This plant is described and diagram- 

 matically illustrated. 



Cooling tanks and milk houses as factors in cream improvement, J. H. 

 Frandsen {Nebraska Sta. Circ. 3 {1917), pp. 19, figs. iS).— This describes and 

 illustrates cream cooling ta^nks and milk houses, and gives the results of winter 

 and summer tests of a square tank built of 2-in. cypress, a square tank insu- 

 lated with 1 in. of ground cork or mineral wool, and a round tank built of 

 2-in. Washington fir. 



In the summer tests it was found that the difference in the results obtained 

 with these three tanks was so slight that one would scarcely be jusified in 

 going to the expense of providing insulation other than that furnished by the 

 wood itself. The water within the tank responded slowly to a change in atmos- 

 pheric temperature. 



" In the winter experiments the tanks were exposed out-of-doors. The only 

 protection given consisted of a double layer of 10-oz. canvas thrown over the 

 top of the tank. In these experiments the water was adjusted at 6 p. m. daily 

 to a temperature at or as near as possible 50° [F.] (the temperature of the well 

 water). Twice daily record was made of the temperature of the cream in each 



