19171 BURAL ECONOMICS. 189 



It is concluded that " a wide range of mixtures of gasoline vapor and air can 

 be used in an engine to give regular firing in all of the cylinders. At half- 

 load and raid-speed on an automobile engine any mixture between 0.055 and 

 0.155 lb. of gasoline per pound of dry air can be fired, and practically full power 

 will be developed between the limits of 0.0G5 and 0.115 lb. The highest power 

 will be developed with a mixture of about 0.08, while the best efficiency will 

 accompany the theoretically perfect mixture of 0.0671 lb. 



"A change of engine speed apparently does not affect the mixture at which 

 the best power or the best eflSciency will be realized, or the ability of the engine 

 to use the leaner mixture, but at the higher speeds a smaller amount of excess 

 gasoline can be used successfully. A change of load does not noticeably affect 

 the points of highest power or efficiency, but at the higher loads a wider range 

 of extreme mixtures can be used. The engine can run idle with as wide a 

 range of mixtures as it can when pulling a good load." 



Rural electric service profitable in Wisconsin {Elect. World, 69 {1911), 

 No. 12, pp. 565, 566). — This is an abstract of a report by F. C. Babson before 

 the Wisconsin Electrical Association, in which the findings and opinions of the 

 1916 committee on rural electrical service were summarized as follows: 



"(1) The construction of purely rural-.service lines is not ordinarily war- 

 ranted unle.ss the saturation of service is such that a reasonable return on the 

 added investment and sale of energy may be shown. (2) Rural-service con- 

 sumers on transmission lines of not over 6,600 volts connecting towns or vil- 

 lages are oi'dinarily profitable if a suitable minimum charge is made. (3) A 

 suitable minimum charge to cover the higher cost of service for rural con- 

 sumers should be made, variously estimated at from ^2 to $3 per month. (4) A 

 low second step in the energy rate should be provided so as to encourage a 

 sufficient use of the service by the farmer to make it practical and attractive." 



Wet weather dryers for hay, H. Hitier {Jour. Agr. Prat., n. ser., 29 {1916), 

 No. 17, pp. 2S9, 290, fig. 1). — A device is described and illustrated to be used 

 as a franjework upon which to stack hay in damp weather so that it will dry 

 properly. 



RURAL ECONOMICS. 



The economic history of American agriculture as a field for study, L. B. 

 Schmidt {Miss. Valley Hist. Rev., S {1916), No. 1, pp. 39--'/.9 ) .— The author 

 points out that this phase of history has not hitherto received the attention at 

 the hands of historians which its importance merits. He has attempted to 

 define the economic history of agriculture as a field for study and to review 

 some of the reasons why special attention should be directed to this field, and 

 suggests some of the more important problems which this field offers for 

 investigation. 



Control factors in agricultural development, J. A. Bonsteel {Univ. Cat. 

 Jour. Agr., i {1917), No. 6, pp. 183, 18ff, 201).— The author has classified the 

 'different factors influencing agricultural production under the head of climate, 

 soil, markets, and human efficiency. He points out that the first two factors 

 are reasonably constant and unchangeable while the other two are purely arti- 

 ficial and change rapidly. He points out some of the adjustments which are 

 necessary in farming for it to keep up with changes in the marketing conditions 

 and in the efficiency of the farming population. 



Country planning, E. A. Waugh {Amer. Civic Assoc. [Pub.], 2. ser., No. 8 

 {1916), pp. 13). — The author points out some of the problems to be solved in 

 country planning, as well as methods of meeting them and organizing the 

 rural communities. He also outlines the purposes, problems, and methods in 

 detail. 



