2SS EXPERIMENT STATIOX EECOED. [Vol. 36 



ference of heat between tv^-o fluids, one of whicli (airl is in the gaseous and 

 the other in the liquid state, is described and illusTrate<3. 



" The liquid to be cooled is contained in a tank in which a ntunber of cooling 

 cylinders revolve. These cylinders are built of galvanized steel sheeting wound 

 in the form of a spiral, the whole forming an enormous cooling surface in a 

 very small space. The lower portion of the cylinders dips in the tank con- 

 taining the liquid to be cooled and air is passed through the annular spaces 

 of the upper half." 



Carburetion. E. E. Deax (Gas Engine. IS {IPIG'^. Xo. 7. pp. S^OS-iS. fig. J). — 

 It is pointevi out in this report that in order to burn kerosene or lower grade 

 distillates efliciently a carbureter is necessary which is capable of " delivering 

 to the manifold, a thoroughly saturated charge, having the correct air-fuel ratio 

 for all velocities, [and a] manifold capable of transporting this charge without 

 change of mixture proportions and delivering it to the combustion space. 



" To overcome the temperature losses due to vaporization and expansion, and 

 assist atomization and vaporization, we must increase the temperanire of the 

 intake air. To prevent deposition of the fuel molecules, along the sides and 

 bottom of passages, resulting in an impoverished mixture, we must apply heat 

 to these surfaces, 



'• It is advisable to apply a limiteil amount of heat to the fuel supply to raise 

 its temperature slightly above its vaporization i>oint." 



Official tests of mechanical cultivation {-Jour. Agr. Prai., n, ser., 29 (1916), 

 Xo. 17. pp. 290. 291). — Plowing tests in light soil of a 4-wheeled tractor with a 

 4-cylinder engine are repKtrted. The weight of the tractor was about 6.650 kg., 

 of which aK>ut 2.000 kg. was on the front wheels. 



"U'hen plowing a furrow 15 cm. deep and 2.42 meters wide at a speed of 3^40 

 meters i^r hour, it was found that 4.902 square meters were plowed per hour 

 with a fxiel consumption per hour of 10.74 kg. and per hectare of 21.9 kg. 

 When plowing a furrow 17.6 cm. deep and 2.4 meters wide at a speed of 3,132 

 meters per hour, it was found that 4,7S4 square meters were plowed per hour 

 with a fuel consumption per hour of 13.2 kg. and per hectare of 27.5 kg. 



Modem piggery buildings, H. W. Ports and A. Bbooks (Agr. Gac. X. S. 

 Wales. 27 (1916), Xo. S. pp. 5o5-o60, pi. 1, figs. 6). — Plans and details of a 

 building especially constructed for the housing of pedigreed stock, with boar 

 sties on one side of the passitge only, are presented. 



The construction cf silos, A. M. KnJSTXX (Cultura. 2S (1916k Xo. SS6. pp. 

 2S5-29.^. pis. S). — Dutch practice in silo construction is described and illus- 

 trated, 



RURAL ECONOMICS. 



The country town. AV. L, Andebsox (.A'f'if Tork: Doubleday, Page d Co., 

 19H. pp. I II +307). — This book endeavors to set forth the rural changes in their 

 historical, scientific, and social aspects. The author concludes that there is 

 no scientific reason for the popular notion that the rural population is under 

 a fatality of evil. Its future is thought to depend almost wholly upon the 

 power of environment, education, commerce, and evangelization, and upon 

 participation in the great movements of the age. 



The social survey: A biblic^raphy. compiled by Z. L. Potteb (Xoir Tork: 

 Russell Sage Foundatiotu 1915. pp. 16). — Among the topics included in this 

 bibliography relating to rural conditions are the purpose and method of rural 

 surveys, rural survey reports, and si>ecial reports regiirding rural health and 

 schools. 



Proceeding of the tliirty-fifth annual session of the Farmers' National 

 Congress of the United States (Farmers' Xat. Cong. U. S., Proc.. So (1915). 

 pp. 209+14]. /»V^- "i*- — The addresses before the congress dealt principally with 



