AMERICAN VINES. 61 



If we take into account the installation of the plant, it is 

 far safer to reckon on one day per acre. 



COST OF TRENCHING OR SUBSOILING WITH STEAM 



WINDING DRUMS. 



Three forms of expenditure must be taken into considera- 

 tion. 



1st. The writing off of the cost of the plant. 



2nd. The wear and tear. 



3rd. The daily cost of the work. 



A. SIMPLE-EFFECT PLANT. 



Average cost 400. This capital is to be written off in 

 eight years. If we assume that we plough 80 poles per day, 

 and work 60 days in the year, we arrive at the following: 



Per Annum. 





 Writing off and interest at 5 per cent. 



of 400 in eight years ... ... 71 



Wear and tear of material at 3 per 



cent, of the capital ... ... 12 



Total ... 83 



Equal to 1 7s. 4d. per day. 



The daily expenditure is reckoned as follows : 



*. d. 

 One engine-driver ... ... 4 9 



Two men ... ... ... 4 9 



One horse and one boy ... ... 4 



One pair bullocks and driver for 



carrying water and fuel ... 4 9 



6cwt. Iqr. 61bs. of coal (8'8 Ibs. per 



horse-power hour for an engine of 



8 horse-power working ten hours), 



at 18s. per ton ... ... 5 8 



Oil, cotton-waste, putty, &c. ... 1 7 



Total ... 1 5 6 

 Plus writing off wear and tear ... 1 7 4 



Daily expenditure ... 2 12 10 



Which brings the cost of ploughing 1 acre to 3 7s. 5d. 



