494 



EXPERIMENT STATION RECORD. 



but the number of trials was limited. With corn and oats, half and half by measure, 

 the rate was 4,103 lbs. per 10 hours with a wind of 26.48 miles 5er hour. This is 

 9S\ bu. ])er day of 10 hours. / 



" In grinding clear oats four trials were made with wind velocities of 19.46, 23.38, 

 24, and 26.67 miles per hour, and 10 hours' work at the observed rates would repre- 

 sent a grinding of 38.7, 50.2, 45. 6, and 54.6 bu., respectively. At wind velocities of 

 25.35 and 25.18 miles per hour rye was ground at the rates of 153.4 and 136.8 bu. per 

 10 hours." 



The observed work ])erformed 1)}' the mill wsis found to agree fairly 

 well with that calculated on the assumption that the effective energy 

 of the mill increased with the square of the velocity of the wind for 

 velocities ])etween 7 and 36 miles per hour. 



The results of the trials of the N Aermotor grinder and 16-foot wind- 

 mill show "that up to 20 miles per hour of wind velocitv the capacity" 

 of the 16-foot windmill was materially greater than that of the 12-foot 

 wheel; but at higher velocities the reverse is true." 



None of the other mills were as effective with the windmills as the 

 gTinders especially designed for them. 



The results obtained with the other mills, using 2i and 5-horsepower 

 engines as the motive powers, are summarized in the following table : 



The computed number of bushels of grain ground to a grade of 4o ])er cent of the finest 

 degree in 10 hours, together with the cost of fuel for the same time. 



"It will be seen from this table that as an average of all the grinding trials with the 

 5-horsepo\\ er engine the cost of fuel per day was $1,775, and for the 25-horsepower 

 engine, $0,885. This is at the rate of 3.55 cts. and 3.54 cts. per hoi'sepower per hour 

 for fuel where gas costs $1.25 per thousand cubic feet. 



" The average amount of corn ground per horsepower per hour was 4.822 bu., equal 

 to 270 lbs., and this is 2,700 lbs. per horsepower for a 10-hour day." 



It is estimated that at the rates ordinarih'- paid the grinding of feed 

 for 3<,) cows for 200 days amounts to al)out $57; the same amount of feed 

 may be ground with a 5-horsepower engine, under the conditions 

 obtaining in these trials, for about $13.50. 



It is stated that $57 '"is 10 per cent interest on a much larger sum 

 than would be required to tit up an automatic grinding plant with the 



