98 ROCK GARDENS 



bed. There will have to be a plug or tap at 

 the lower end of the pipe, in such a position 

 that it can be easily got at, and the end which 

 is in the hollow should be covered with per- 

 forated zinc to prevent it getting choked. 



Having fixed this pipe, build a wall of 

 concrete, or bricks if preferred, round the sides 

 of the hollow, about 4 to 6 inches thick, and 

 about 10 inches high, making sure that the 

 top of this wall is approximately on the same 

 level all round. 



On the lower side, and about 8 inches from 

 the bottom, fix a pipe of about i|-inch bore. 

 This will act as an overflow, and also conduct 

 the water to the next marshy spot and keep 

 the water in the hollow at a constant level, 

 and should have its end covered with per- 

 forated zinc. This being in position, put a 

 layer of about ^-inch thick of pure cement 

 all over the bottom and sides to ensure their 

 being water-tight. 



It is advisable to put on the cement before 

 the concrete has set very hard, say on the 

 following day, for it will be found to bind 

 together better and not be liable to chip off. 



