96 INSTALLATION OF TRENCHING OR SUBSOILING PLANT. 



It will be interesting to compare these figures with those- 

 given later on for drums worked by steam power, to study 

 the limits of economy of both systems. 



The complete plant (drum, cable, pulley, plough) is worth 

 from 80 to 100, which has to be written off in ten years. 

 The steel traction cable costs from 4d. to 6d. per pound,* 

 and weighs from 12 to 13 ounces per yard. A cable lasts 

 from 150 to 200 days. 



Under favorable conditions the cost of trenching or sub- 

 soiling 1 acre with horse-winding drums is under 6 8s.; if 

 it exceeds this figure it is advisable to have recourse to other 

 means for the execution of the work. 



* These prices are subject to market fluctuations. 



