236 



CANADIAN FARM YEAR BOOK. 



Horse-Power. — In rating machin- 

 ery, It Is customary to express the 

 power delivered or consumed In 

 "horse-power." One horse-power re- 

 quires that 33,000 foot-pounds of 

 work be done each minute, or 550 

 foot-pounds per second. 



Efficiency. — The efficiency of a ma- 

 chine Is the ratio of the work which 



It delivers to the work which Is put 

 on to it, or what is the same thing, 

 the ratio of the power delivered to 

 the power consumed. 



Watts — Kilowatts. — In rating elec- 

 trical machinery, the power Is often 

 expressed In watts or kilowatts (1000 

 watts). Seven hundred and forty-six 

 watts equal one horse-power. 



The Windmill. 



It has been found by experience 

 that It requires, on an average, a 

 wind velocity of four or five miles 

 an hour to drive a windmill, and that 



the mill will run, on an average, eight 

 hours a day. The average velocity of 

 wind in Canada for eight hours per 

 day is about 16 miles an hour. 



Velocity of Wind and Pressure Exerted. 



Force of Winds. 



Hardly perceptible. 

 Just perceptible. 



Gentle, pleasant wind. 



Pleasant, brisk gale. 



Very brisk. 



High Wind. 



Very heavy storm. 



Great storm. A hurricane that 

 blows down trees, buildings, 

 etc. 



Horse-Power of WlndmUl. 



An 8-foot windmill In a 15-mIle- 

 an-hour wind will pump 2,450 im- 

 perial gallons of water a total height 

 of 50 feet In 8 hours. With the for- 

 mula as used for H.P., we find the 

 horse-power of windmill and pump 



in a wind of this velocity is .077 h.p., 

 or about 1-13 h.p. 



A 10-fo6t windmill in a 15-mile-an- 

 hour wind can pump 3,000 Imnerlal 

 gallons to a total height of 85 feet 

 in 8 hours. From the same formula 

 this mill has .16, or about 1-6 h.p. 



Water Power. 



Water-power Is not available on 

 a majority of farms, and mechanical 

 engines are fast taking the place for- 

 merly held by water-power appli- 

 ances. Water motors are divided into 

 three classes: (1) water wheels, (2) 

 Impulse wheels, and (3) turbines. 



Water wheels have become out of 

 date and very little used In Canada. 

 The Impulse wheel is so arranged 

 that a stream of water from a nozzle 



strikes the buckets. The turbine Is 

 designed to use a large auantitv of 

 water on low heads. It is used on 

 heads from 3 to 150 feet and over. 

 A turbine 2 feet in diameter on a 5- 

 foot head produces 6 h.p. In doing 

 this it uses 900 cubic feet of water 

 per minute, and makes 200 revolu- 

 tions per minute. 



To find the H.P. of a stream, use 

 the same calculation as used in other 



