CHAPTER XIII. 



Draining Necessity for Gradient of the trenches 

 Frequency of occurrence Mr. Wall's opinion Draining 

 swamps Mauritius grass. 



NEARLY all coffee estates being situated more or 

 less on hill slopes, their surface soil is liable to be 

 washed away during the heavy rains of the mon- 

 soon. In order to prevent this, recourse must be 

 had to continuous trenches or drains dug across the 

 face of the slope, and the more frequently these 

 occur the better. 



These trenches will not merely prevent the soil 

 from being carried off, but will benefit the land in 

 other ways, as will soon be evidenced by the 

 appearance of the plants in their immediate neigh- 

 bourhood. The trenches should be pretty nearly 

 level, especially if near each other, though a slight 

 gradient will be desirable in order to allow the 

 gradual escape of surplus rainfall ; otherwise they 

 will be constantly in danger of overflowing or 

 bursting, and thus causing damage. The fewer 



