MANUAL FOR SUGAR GROWERS. 37 



terial lias been found to answer most successfully ; 

 the other forms of drain are found, sooner or later, 

 to become filled with earth and are thus rendered 

 useless, whereas the earthenware drain-pipe prop- 

 erly laid will remain in good order for a long term 

 of years, probably twenty or thirty. 



The actual operation of laying tile drains in a 

 piece of land is one which requires careful consid- 

 eration beforehand, and if possible the work should 

 be conducted by workmen having practical knowl- 

 edge and experience of tile-laying. The points to 

 be considered are, the size of pipe required, the 

 depth of the drains, and their distance apart. For 

 most work pipes having an internal diameter of one 

 and a half inch will serve for the drains, and if 

 these are connected with a main drain, as they fre- 

 quently require to be, this main drain must be of 

 sufficient capacity to remove freely all the water 

 collected by the small secondary drains, and its size 

 will be determined by their number. In laying 

 tiles, levels are carefully taken, and trenches are 

 opened, with specially shaped tools, to the required 

 depth ; care is taken that the earth at the bottom of 

 the trench is disturbed as little as possible, all 

 treading or walking in the trench being avoided ; 

 the tiles are laid end to end, and the joint is covered 



with a short length of pipe 



of larger size, as shown B =z 



in the figure ; the earth Fia - 7. Diagram of pipes and joints 

 Pj , in tile drain. 



is returned to the trench 



and is firmly pressed down. It is desirable to leave 



the earth at the surface somewhat raised over the 



