1917J RURAL ECONOMICS. 789 



dry, level, earth road, with the tractor travelinp; at its rated plowing speed ; 

 (2) that the belt horsepower rating must express the horsepower that the 

 manufacturer will guarantee the engine of his tractor — when in good condition 

 and properly operated at normal speed — to deliver at the belt pulley continu- 

 ously for two hours." 



Farm buildings, with plans and descriptions, H. A. Sheaber {Chicago: 

 Frederick J. Drake d Co., 1917, pp. 256, figs. IJfS). — This book contains the fol- 

 lowing chapters : Economy of good farm buildings ; two kinds of barn con- 

 struction ; horse and cow barn ; enlarged dairy and horse barn ; dairy barn 

 for 28 cows ; dairy barn for 30 cows ; monitor roof dairy stable ; new models for 

 farm barns ; miscellaneous farm buildings ; hog houses for winter and summer ; 

 poultry, poultry houses, and poultry furniture ; concrete on the farm ; comfort- 

 able farm homes ; and dictionary of building and architectural terms. 



Considerable space is devoted to the chapter on comfortable farm homes, 

 which includes plans and information regarding the construction of several 

 types and sizes of farm dwelling. The section on the farm septic tank con- 

 tains, among other matters, the following new information regarding sewage 

 purification : 



" A septic tank provides a scientific means of rendering sewage harmless. 

 . . . Two kinds of bacteria work in a septic tank. Aerobic bacteria work in 

 the first compartment and anaerobic bacteria work in the second compart- 

 ment. . . . The size of the septic tank varies according to the amount of sew- 

 age to be disposed of. The capacity of the first box or compartment should be 

 sufficient to hold two days' or three days' sewage before it runs over into the 

 second compartment. The second compartment should be about the size of the 

 first. . . . The final discharge from the septic tank is supposed to be inoffensive 

 but it is generally reconnuended to discharge into 4-in. draintile so that the 

 water can percolate away." 



Silo building, W. D. Nicholls (Univ. Ky. Col. Agr., Ext. Div. Circ. 48 (1917), 

 pp. 7). — This is a brief note on silo building in Kentucky. 



Pit silos, T. P. Metcalf and G. A. Scott (U. S. Dept. Agr., Farmers' Bui. 

 825 {1917), pp. 14, figs. 6). — This bulletin gives directions for constructing pit 

 silos, indicating the proper size and best location, and describes the practices 

 which have proved most satisfactory. 



" Underground silos should be constructed only in soils that are firm and 

 free from rocks, sand strata, and seeps, and where the water table is always 

 below the bottom of the floor after they are dug. . . . The construction of pit 

 silos is recommended only where a combination of soil and climatic conditions 

 exists such as is found in the Great Plains region." 



Reinforced concrete silos and small grain bins, E. S. Fowler {Proc. Nat. 

 Assoc. Cement Users, 9 {WIS), pp. 498-510, figs. 7).— This article reviews sta- 

 tistical data on concrete silo construction and gives information regarding 

 small concrete grain bins and tanks. 



RURAL ECONOMICS. 



Farm management [in Missouri], O. R. Johnson and R. M. Green (Missouri 

 Sta. Bui. 147 (1917), pp. 38-40).— In these pages attention is called to the re- 

 sults of a survey to determine the cost of living in Missouri. It was found that 

 the total cost of living on 191 farms in Saline County was $555.80, of which 

 the farm furnished $239.80, while on 198 farms in Dade County the total cost 

 was $406.80, of which the farm furnished $173.80. Data are also shown regard- 

 ing animal units on Missouri farms, and the distribution of man and horse 

 labor for various farm crops and live stock. 



