590 EXPERIMENT STATION EECORD. 



yives data upuu their perforinaiK-L- imdcr different couditions. Siuee wind 

 pressure increases as the square of the velocity it follows that the product of 

 speed and pressure increases as the cube of the velocity. The power of the 

 windmill should therefore vary in the same proportion, hence in order to use 

 as nnich as possible of the force of the wind the mill should operate machinery 

 in which the load increases somewhat in the same proportion as the wind 

 pressure increases with the velocity. For this reason a centrifugal pump works 

 well in combination with a windmill, likewise a constant potential generator 

 for charging storage batteries. Results of experiments by the Danish govern- 

 ment are quoted, giving rules for dimensioning and weathering the sails. 



Experin)ents in England conducted by the Royal Agricultural Society are 

 also cited. The dimensions of the mill securing first prize are given in detail. 

 From an analysis of the performance of the various mills it is found that 

 " nothing is gained by providing sail area for more than about 6G per cent 

 of the total surface of the wheel." 



" The most suitable angle of weather for the tips of the vanes appears to 

 be about 35 degrees when their velocity is the same as that of the wind. The 

 best number of vanes apitears to be a mooted question." 



The windmill as a farm power (Farm Implements. 20 (1906), Xo. D, pp. 

 •'/---'/'/)■ — A popular article transcribed from the Caimdhui Tlircshertnun ainl 

 Farmer, giving a historical sketch of the development of the windmill and 

 citing some of the experiments which have been conducted from time to time 

 with a view to increasing its efficienc.v and suitabilit.v as a farm and general 

 utility motor. 



Dynamo run by windmill (Eufjiii. and ]\Iiu. Jour.. S.i (1906). yo. 21, p. 

 976). — An electric lighting plant operated by wind power is reported to have 

 been installed at Noblesville, Ind., consisting in part of a 1-1-ft. windmill on a 

 50-ft. tower. The windmill operates a plunger pump delivering water to a 

 reservoir where pressure is maintained constant by automatic devices. The 

 water under pressure is used when necessary to drive a 5-horsepower turbine 

 wheel, direct-connected to a 1-horsepower, 25-volt dynamo which charges a 

 storage battery. The battery is of sufficient capacity to light twenty 8-candle- 

 power lamps for 'i hours. In order to generate sufficient current for winter 

 use the windmill must operate 5 hours ]ier day, and for sunnner use, 2 hours 

 per day. 



Test of a small gasoline electric light plant ((Jas Engine, S (1906). Nv. 11, 

 pp. .i'lH, 3.'i9). — This is a report upon a test of a plant of a type used for the 

 lighting of farm residences, barns, and other buildings by the electric incandes- 

 cent lamp. The engine is belt-connected to the generator and may be used for 

 other power purposes. The test was conducted at the Kansas Agricultural Col- 

 lege and showed that for a full load of eighteen 16-candlepower, 110-volt incan- 

 descent lamps, the fuel consumption was 1.35 qts. of gasoline per hour. This 

 makes tlie cost per horsepower hour, ^0.0253, with gasoline selling at 15 cts. per 

 gallon. The fluctuation of voltage was found to be less than 1 per cent when 

 operating at a normal pressure of 110 volts, and the variation in light as com- 

 pared with lamps supplied with current from the usual steam plant was found 

 to he hardly appreciable. 



Explosion motors and the injection of volatile liquids, K. Schreber (Rev. 

 Gen. Sci., 11 (1906), A'o. 16, pp. 7.3'/-? '/J, figs. 5). — A mathematical discussion of 

 the desirabilit.y of injecting cooling water into the working cylinder of the gas 

 engine. It is concluded that the method of injecting water at the moment of 

 explosion is neither effective nor economical. The author advances particularly 



