THE ARTIFICIAL ROCK GARDEN 63 



at which to do it, and not after the rock- 

 work is finished. It is hardly necessary to say 

 that the real effect cannot be judged until after 

 your rocks have been placed in position ; but 

 please remember that the hills and banks are 

 not made to grow rocks, but that the rocks 

 are placed there to keep up the soil in which 

 the plants are to grow. Without the rocks 

 the soil on any steep gradient would soon be 

 washed down, although there is an angle, called 

 " the angle of repose,'' at which soils of every 

 description will remain stationary. But this 

 angle is generally of a far more gentle gradient 

 than is suitable for a rock garden, therefore it 

 will be necessary to adopt the other alternative 

 and build the slope up in the form of terraces, 

 each of which will, in all probability, have 

 a gradient considerably less acute than the 

 " angle of repose," and there will, therefore, be 

 less chance of the soil being washed down by 

 heavy rains. 



