RURAL ECONOMICS. 489 



Design and operating features of motor- driven pumps, C. A. Carpenter 

 (Elect. World, 61 (1913), No. 24, pp. 1309, 1310, figs. 2).— In a study of the de- 

 sign of motor-driven centrifugal pumps the author, by a mathematical discus- 

 sion and a unit speed comparisou of centrifugal pumps of homologous design, 

 shows that a particular design of pump for best effect and at ideal conditions 

 has one unit speed, and that only special conditions can be met by such a 

 pump with fixed speeds. He concludes that for motor-driven pumping ma- 

 chinery established design can not be depended upon and that special design is 

 necessary. High efficiency is desirable, and the horsepower characteristics, in- 

 cluding the maximum and starting horsepower, must be such that the motor 

 can not be dangerously overloaded. 



[Cost and service comparisons of motor trucks and horse-drawTi vehicles], 

 C. Brettell (School Mines Quart., 3.', (1913), No. 3, pp. 241-258, figs. 6; abs. 

 Engin. and Contract., 39 (1913), No. 20, pp. 538-542, figs. 4).— Curves and data 

 are given from several years' comparative tests of the speed, convenience, re- 

 liability, and economy of motor and horse-drawn trucks. The comparison of 

 economies is based on cost per ton mile, computed from both the fixed and the 

 variable or mileage charges. 



The results in genei'al are in favor of the motor truck. For low daily 

 mileages up to IS miles the 3-horse truck is more economical owing to the 

 time required in loading and unloading, but the motor truck has the advantage 

 of being able to operate economically over a daily mileage varying from 15 to 

 75 miles. In addition quick loading and unloading devices are being put on 

 the market which the tests indicate will allow motor trucks to operate at 

 a low daily mileage with an economy equal to or greater than the horse 

 trucks, since the average daily mileage for a horse truck is taken at only 10 or 

 12 miles, thus greatly increasing the ton mile cost. 



Comparison of different kinds of silos, M. L. King (Amer. Thresherman, 16 

 (1913), No. 2, pp. 82, 83). — In a comparison of 10 different types of silos a 

 table is given in which the different types are arranged in the order of their 

 relative merits, as regarded by the author, in regard to tightness and rigidity, 

 durability, cost, amount of care required, convenience, and frost-proof qualities. 

 The Iowa silo of reenforced hollow tile is placed first among the different types, 

 with the stave silo and concrete and cement silos following. 



The construction of silos in stone and brick, W. S. H. Cleghorne {Agr. 

 Jour. Union So. Africa, 5 (1913), No. 4, pp. 535-545, figs. 5). — This article gives 

 information to be used in the construction of both pit and above-ground silos 

 and furnishes detailed plans for a square silo in stone or brick, which it is 

 stated is the type of silo most likely to be built by the farmers of South Africa. 



RURAL ECONOMICS. 



Social and economic survey of a rural township in southern Minnesota, 

 C. W. Thompson and G. P. Warber (Univ. Minn. Studies Econ., 1913, No. 1, 

 pp. V+75, pis. 11, figs. 4I). — This publication presents the results of a special 

 survey covering a township in southern Minnesota, conducted by the Bureau 

 of Research in Agricultural Economics of the University of Minnesota. It 

 takes into consideration the various social, economic, political, educational, and 

 religious activities in the township and their relation to the larger country life 

 of which they are a part. The data were obtained first-hand from 136 rural 

 fnmilies living within the township as well as from the various markets and 

 ether agencies tributary to this region. 



The population is shown to be made up as follows: Swedish 2.9 per cent, 

 Irish 3.7 per cent, English 5.8 per cent, American 11 per cent, mixed 21.3 per 



