590 EXPERIMENT STATION EECOED. 



lined in some detail. In connection with the practical application of electric 

 power to the belt work of farms a table of useful data is given showing the 

 amount of power required and the cost of performing several farm operations 

 at various rates. 



It is concluded that electric motors can be profitably used almost daily 

 in many farm processes because of their convenience, ease of operation, flexi- 

 bility, lack of noise and dirt, long life, small repair charges, and general econ- 

 omy, but that it is usually uneconomical for farmers to own and operate Iso- 

 lated plants since the fixed charges are high and such plants are not well 

 adapted to supplying motors with power. It seems preferable and more profit- 

 able to distribute power from a central electric plant by means of a high voltage 

 distribution system. "The best system will usually be found to be a three- 

 phase system, either 3 or 4 wire, with a voltage such that standard 2,200 or 

 6,600 volt distributing transformers can be used." 



Small central stations supplying power to farmers only and with no other 

 market are not thought to prove successful financially. Distribution from a 

 city central electric station or a long distance high voltage transmission line is 

 recommended where feasible. 



Mechanical efaciency of gasoline engines, S. F. Wilson (Power, 38 (1913), 

 Ifo. 18, p. 605). — A method for closely approximating the mechanical efficiency 

 of gasoline engines of the hit-and-miss type with constant gasoline level feed 

 is suggested which is based on the number of explosions at full and no load. 



The formula for this method is : Mechanical efficiency= ^~~ ^ . in this formula 



Ne 



Nc equals the number of explosions per minute at full load and No equals the 

 number of explosions per minute at no load. 



Thrashing with steam engine or electric motor, P. Tietz (Deut. Landw. 

 Fresse, 40 (1913), Nos. 82, pp. 919-981; 83, pp. 995-9P7) .—Comparative tests 

 were made of steam and electric power for thrashing on 2 farms. On the 

 first farm a thrasher with a 22 by 60 in. cylinder was driven by a 32 h. p. 

 electric motor and by a 25 h. p. portable steam engine. On the second farm a 

 thrasher with a 24 by 66 in. cylinder was driven by a 40 h. p. motor and a 31 h. p. 

 portable steam engine. 



The results show little difference in the amounts of grain lost by the 2 kinds 

 of power, the loss being below 0.3 per cent in both cases. The results on cost 

 per horsepower hour, total accomplishment, si^eed, efficiency, etc., show that in 

 both sets of tests the steam engines were essentially cheaper and more efficient 

 than the electric motors. 



The present state of motor cultivation in Germany, G. Fischer (Intemat. 

 Inst. Agr. [Rome], Mo. Bui. Agr. Intel, and Plant Diseases, 4 (1913), No. 6, pp. 852- 

 858, pis. S). — The author describes and compares a few German makes of motor 

 plows and motor scarifiers and also some American makes of plows and tractors 

 which have proved most successful in German agriculture. 



He states that the so-called " Stock " motor plow has given the best results 

 technically and practically as a cheap mechanical plow suited to small farms 

 and to the shallow tillage of light soils. A summary of results obtained with 

 motor plows in Germany shows that for shallow and moderately deep plovdng 

 of light and medium soils some very useful machines exist. Gradients above 

 one in ten and numerous big stones are said to offer considerable difficulties, 

 although the American plows are for the most part protected from breakage 

 by stones by means of wooden pegs. The American tractors are said to work 

 best on hard soils, while on soft soils plows of the Stock type are preferable. 

 Disk plows are said to penetrate more easily to considerable depth than the 

 other types. 



