RURAL ENGINEERING. 187 



information is given regarding steam, gas, and electricity, and some space is 

 devoted to the more refined methods used in engineering practice for improv- 

 ing the economy of various motors. It is the opinion of the author that a 

 knowledge of the best engineering practice is not only of considerable educa- 

 tional value but will lead to the more perfect manipulation of the simple farm 

 motors. 



" While this book was prepared primarily as a text-book for students in agri- 

 cultural engineering, the subject matter is so presented that it will be of equal 

 value to farmers and to operators of various kinds of engines and motors." 



The adaptation of kerosene to g'asoline engines, G. A. Richtee and B. L. 

 Pierce (Sci. Amer. Sup., 77 (.19U), Xo. WS/f, pp. 22, 23, figs. 5).— The experi- 

 menters confined themselves to the utilization of kerosene with special ref- 

 erence to water injection methods. A single cylinder 4-cycle engine rated at 

 5i horsepower at GoO revolutions per minute was used. The method of water 

 injection consisted of a jacketed intake pipe terminating below in a T connec- 

 tion, which was fitted with elbows. A carbureter was fitted into each of the 

 two elbows, with the idea of injecting both the kerosene and the water by means 

 of respective vaporizers. 



Kerosene when used alone caused excessive cylinder carbonization, but the 

 injection of water with the kerosene cooled the cylinder walls, removed carbon 

 and tended to prevent its deposit to an objectionable degree, and reduced the 

 violence of the explosions. The injection of water also appreciably increased 

 the thermal efficiency, the maximum efficiency being observed when the ratio 

 of water to kerosene was 22:100 by weight. Absolute control of this ratio 

 was not necessary as this maximum efficiency remained practically constant for 

 several points to either side. Cylinder carbonization was decreased 82 per 

 cent by injecting water with kero-sene, and an oxidizing solution of ammonium 

 nitrate increased this value to 88 per cent, but its use was not warranted. 

 Spark plugs with long points were more satisfactory than those with short 

 points when kerosene was used. 



The water jacketed intake heated to a temperature of 60° C. is considered 

 sufficient to give satisfactory carburetion with kerosene. " TTie field ad- 

 vantageously affected in efficiency by water injection is limited from one-third 

 to full load for the engine in question." 



The use of internal-combustion motors in Danish agriculture, C. L. Feil- 

 BERG (X. Cong. Intemat. Agr. Gand. 1913, Sect. 4, Question 1, pp. 8). — ^A review 

 of statistical data indicates steady progress in the use of internal-combustion 

 power in Danish agriculture. The 2-cycle crude oil motors of domestic manu- 

 facture are said to be preferred. Private electrical systems are usually in- 

 stalled on the larger estates using crude oil motors for power. On medium 

 sized estates portable and stationary internal-combustion motors are more used, 

 with various methods of mechanical transmission of power. The smaller agri- 

 culturists rarely use internal-combustion motors but often belong to electrical 

 associations and use small portable electric motors. 



The science of laying out and the art of plowing with power (Peoria, III., 

 1913, pp. 8, figs. 7). — This work is diagrammatically illustrated. 



Recent tests of mechanical cultivation in France, G. Coupan (X. Cong. 

 Intemat. Agr. Gand. 1913, Sect. 4, Question 1, pp. 13). — A discussion and com- 

 parison of the more recent mechanical cultivation experiments in France, in 

 which the conclusion is drawn that the different tests have not given suffi- 

 ciently concordant results regarding the direct purpose of the tractor. This is 

 attributed to the extreme difficulty of eliminating all the causes of error. For 



50128°— No. 2—14 7 



