240 THE RUBBER TREE BOOK 



as is frequently the case in Ceylon, their construction is almost 

 an impossibility. 



In such cases terracing although the first outlay is ex- 

 pensiveis a much better solution of the difficulty. Where 

 no stones are available, as in Sumatra, belts of guinea-grass 

 are often employed to prevent wash. These cost little like 

 politeness and, like it, are worth much. The cost of these 



> HEVEA TREE 



RETAINING DRAINS 



FIG. 65. Diagram of Water-pits for Retaining Soil-wash. 



on a well-known Java estate has been found in practice to be 

 from one shilling and sixpence to two shillings per acre. 



When the Heveas have reached a more advanced age their 

 roots, well spread throughout the soil, assist in binding it to- 

 gether, but for some years breakwaters of some kind are indis- 

 pensable on hilly land. 



While methods may have to vary in different countries and 

 under different conditions, it is clear that in all cases effective 



