PRELIMINARY OPERATIONS 



99 



means bringing the drain pipes perilously near the spade when 

 trenching operations are in progress, and should only be adopted 

 when the soil is exceptionally heavy. 



\Yhether a main drainage system is installed or not, it is 

 essential on almost any soil except the very lightest that provi- 



FIG. 46. Drainage system for a stiff soiL 



sion should be made for carrying off the surface water. As the 

 cultivated ground will, in a year or two, be at a higher level than 

 the paths, the surplus surface water will tend to run into the 

 paths, and the surface drains are therefore most conveniently 

 laid in the paths. These surface drains are very simply made, 

 and there is no reason why the boys should not themselves 



