464 



On the Cost of Horse-power. 



Horse-labour on Whitfield Farm. 



These fio;ures represent the cwts. drawn ( = lifted) one mile in 

 the several operations ; and, adding them together, we have the 

 annual labour of the farm, which amounted, in the case before us, 

 to 37,105 cwt. drawn (= lifted) one mile per annum. For the 

 words " per annum " we may substitute 300 days of 9 hours each, 

 and the work done will be found on calculation to have been equal 

 to the lift of 135,450 lbs. one foot high per minute during all that 

 time ; which, as 7 horses were employed, was 16,492 lbs. apiece, 

 or about one-half the theoretical quantity- — a very high average, 

 however, as w^ill appear from what I have already said. In order 

 to ascertain the cost of horse-power in this case, we must assume 

 a rate of movement natural to the draught animal — say 2\ miles 

 per hour. Tlie work done was 37,106 cwts. drawn (= lifted) one 

 mile in 2700 hours : this is equivalent to 14,842 cwts. drawn 2-| 

 miles in 2700 hours, or 5^ cwts. drawn that distance every hour. 

 But the cost of horse labour on this farm was 381/. 10^. per annum, 

 or 2s. lOfZ. per hour — that then was the cost of drawing (= lifting) 

 b\ cwts. 2\ miles in that time. Horse-power on Whitfield larra 

 thus cost as nearly as possible 6r/. per cwt. drawn 2i^ miles at that 

 rate of movement. If tlie ploughing of an acre was equal to 

 lifting 3 cwt. 10 miles, then by horse-power it was done for 65. ; 

 if it was equal to lifting 5 cwt 8 miles (I name fewer miles,- 

 because the greater draught implies greater depth of ploughing, 

 and deeper ploughing involves a wider furrow-slice), then it cost 

 8s. per acre. And these are the figures with which an engineer 

 would have to compare the performance of his engine. 



Take now the case of Mr. Melvin's farm. In order to under- 

 stand some of the figures in the cartage columns of the following 

 Table, it is necessary to extract the following particulars from 



