282 EXPERIMENT STATION RECORD. 



pression, and the sliding and siulcing of the drive wheels. It is concluded not 

 only that external conditions exert a strong influence on the general behavior 

 of the motor plow, but also that the same differences in external conditions 

 produce unlike effects in the operation of the different individual plows. 



Threshing with electricity in Iowa, F. S. Dewey {Elect. World, 64 (19 W, 

 No. 8, pp. 378, 379, figs. 2). — Results obtainetl on several threshing jobs with an 

 electrical threshing outfit owned by a neighborhood association in Iowa are 

 i-eix)rted. 



The electrical equipment consisted of a 30-horsepower. 220-volt, 60-cycle, 

 single-phase motor, operating at 1,165 R. P. M., and provided with pulley sizes 

 to obtain three different speeds according to the kind and condition of the grain 

 threshed. The threshing machine cylinder measured 32 in. with a 54-in. 

 separator. 



On five tests with barley, 1,150, 1,800, 1,045, 1,375, and 1,045 bu. were threshed 

 with 140, 278, 160, 170, and 100 kilowatt hours, respectively. In two tests with 

 oats, 1,125 and 720 bu. were threshed with 73 and 67 kilowatt hours, respectively. 



In threshing barley a cylinder si^eed of about 1,100 R. P. M. was found to be 

 most satisfactory. An advantage of the electric motor is said to be that the 

 constant speed obtainable does not carry the grain over into the straw pile. 

 It is thought that with electrical energy at 5 cts. per kilowatt-hour the operating 

 expense will be 25 per cent less than that of a steam engine. 



Performance tests of sug'arhouse heating and evaporating apparatus, 

 E. W. Kerr et al. (Louisiana Stas. Bui. 1^9 (1914). PP- 178, pi. 1. figs. 64).— 

 This bulletin reports a partial repetition and a continuation of laboratory ex- 

 periments reported in Bulletin 138 (E. S. R., 28, p. 893), and the results of per- 

 formance tests made on a large number of full size sugarhouse apparatus in 

 Louisiana and Porto Rico. 



The results obtained in the laboratory as regards the effect of air in the heat- 

 ing steam, of hydrostatic head, and of the quality of the steam on the coefficient 

 of heat transmission were practically the same as those found in the previous 

 experiments. Other conditions being equal, the lower the temperature and density 

 of the heating steam, the smaller was this coefficient. " Increasing the density 

 of the boiling liquid causes a loss in heat transmission due to the decrease in 

 temperature fall according to the equation y—CD^^, in which C=a constant 

 and D= density in degrees Brix. The total loss due to the density of the 

 boiling liquid seems to be in excess of that due to loss of temperature fall. . . . 

 The vapors evolved from liquor of high density or from liquor under hydro- 

 static head are superheated. The entrainment was less in the double tube 

 calandria than in the standard calandria. . . . Within reasonable limits the 

 coefficient of heat transmission seems to be independent of the temperature 

 fall . . . and of the temperature of juice feed. The coefficients . . . obtained 

 in the small laboratary apparatus were much higher than are obtained in full 

 size evaporators. . . . The great temperature fall required in the last body 

 of a multiple evaporator is due to the combined influence of greater amounts 

 of air, steam of lower density, liquid of higher density, also in many cases, 

 more foul heating surfaces than in preceding bodies. The downtake or circu- 

 lation tube increased heat transmission materially. Long tubes give better re- 

 sults as to heat transmission than short tubes, due to better circulation. The 

 double tube and the baffle plate calandria gave greatly increased heat trans- 

 mission as compared with the standard types tested, indicating that attention to 

 steam distribution and the removal of incondensable gases is very important. 



The object of the sugar factory experiments was to obtain data regarding 

 the capacity and economy of evaporating and heating apparatus, including 

 multiple effects, vacuum pans and heaters, and data regarding barometric jet 



