88 EXPERIMENT STATION RECORD. 



Crete work should be raised by 25 per cent ; that a given strength of concrete 

 should be speeifipd instead of a given mix; and that cement should be sold by 

 volume ii .tead of weight and in paper bags containing 1 cu. ft. 



Test of a kerosene oil engine, H. D. Wile {Elect. World, 62 (1913), No. 8, 

 p. S89, fig. 1). — The engine tested resembles the ordinary 4-stroke-cycle, 

 throttling-governor, stationary engine with mechanically operated valves and 

 make and break ignition. A 7.5 K. W. generator was directly connected. The 

 mixer, situated on top of the cylinder, supplies both water and fuel, which are 

 atomized by the piston suction. Four series of tests were made as to jacket 

 water temperature, time of ignition, amount of water in the cylinder, and 

 economy run. 



The most efficient jacket water temperature was found to be around 175° F. 

 and the best angle of advance of ignition was 36, as compared with the aver- 

 age angle of 16° for gasoline engines. Water in the cylinder performs four 

 duties, namely, prevents rapid explosions, excessive pressures, high tempera- 

 tures, and the heavy deposit of carbon on the walls of the cylinder. Other 

 points brought out are that the best ratio of kerosene to water in the mixer 

 was as 3 : 1 and that the addition of more water decreased the thermal efficiency ; 

 that the percentage of heat absorbed by the jacket water was approximately 

 16 per cent ; and that the heat lost in radiation and exhaust was approximately 

 55 per cent. The fuel economy was considered good, 0.872 lb. of kerosene per 

 brake horsepower being the lowest consumption, which indicates that nonvola- 

 tile or low-grade fuels can be burned successfully in small units. 



Comparison of cost of fuel for oil, gas, and steam engines and current 

 for electric motor, W. A. Kritzee {Gas Engine, 15 {1913), No. 6, pp. 316, 

 Sit). — Several tables of data are given showing the cost of fuel per brake 

 horsepower for 1 hour, for 24 hours, for 300 days of 10 hours each, and for 300 

 days of 24 hours each, using the maximum, average, and minimum prices for 

 the fuel. 



Wind power, Vogdt {Deut. Landw. Presse, 40 {1913), No. 49, pp. 590, 591, 

 flgs^ Sy — The results of experiments with wind power indicate that the pressure 

 of the wind on a wind motor per unit area increases with the square of the 

 wind velocity, and the horsepower with the cube of the wind velocity, including 

 skin friction. Under these conditions it is stated that the speed of a windmill 

 wheel is directly proportional to the wind velocity. On this basis the following 

 formula is suggested to determine approximately the available power of a 



V X F y. v^ 



windmill for certain wind velocities: N= j^q- — -. In this y equals the 



weight of 1 cubic meter of air in kilograms; F the average area in square meters 

 of the windmill wheel at right angles to the direction of the wind; v the wind 

 velocity in meters per second ; and fir 0.81 meters per second or the acceleration 

 due to gravity. In this connection it is claimed that the efficiency of the wind 

 power plants which have been tested vary between 05 and 80 per cent. The 

 operations of several wind motors are described. 



Electricity on the western farm {Jour. Electricity, 30 {1913), No. 25, pp. 

 576, 577). — This article gives operating data and rate schedules of several power 

 companies supplying electrical power to farms throughout the Western States. 



The rate schedules show a great difference in the methods of charging for 

 power and the amount of the charge. The greatest demand for electrical power 

 appears to be for irrigation pumping, so that the use of electricity in these cases 

 is necessarily a seasonal use. It is concluded, therefore, that it is to the 

 advantage of power companies to have the consumer make his installation small 



