FARM EQUIPMENT 359 



machinery cost of 2 to 5 cents for each hour of horse labor. 

 This usually amounts to a cost of 75 cents to $2 for each 

 acre of crops grown. In regions like Minnesota, the 

 machinery cost is probably 20 per cent of its value, but 

 since more acres of crops are grown the cost is less 

 per acre. 



228. Duty of machinery. The number of acres that 

 one may expect a machine to work is sometimes called 

 the duty of machinery. An average of a large number of 

 estimates of rates of work for different machines gave 1.4 

 acres as a day's work for each foot wide that the machine 

 covers. That is, a day's work for an average machine 

 that completes one foot at a trip would be 1.4 acres per 

 day, and for a machine that covers 6 feet, it would be 8.4 

 acres per day. 



The rates of work varied from 1 acre per day for each 

 foot covered by the machine to over 2 acres. One acre 

 per day is very slow work, and 1.75 acres is rapid work. 

 It is usually safe to estimate that a machine of light 

 draft with good horses will cover 1.5 acres for each foot 

 that it is wide. If the machine is a heavy one, it the 

 horses are slow, if the fields are small, or if there are delays, 

 the rate of work will be much less. 



If one knows the period in which the work is to be done 

 and the probable proportion of days on which work can 

 be done, he can make an approximate estimate of the 

 acres that a machine can handle. 



Suppose that one wishes to be able to make all his 

 timothy hay in a period of about two weeks, and that in 

 his climate he can count on two-thirds of the days being 

 suitable for haying, he would then expect about 8 days on 

 which the mower could be used. If a six-foot mower is 

 drawn by two fairly good horses, it will be a machine of 



