APPENDIX. 155 



soil, the latter are likely to crumble away under 

 the great weight on top ; to prevent which, 

 should any difficulty be experienced in obtaining 

 tiles or flags of a sufficient length, it becomes 

 necessary either to put brickwork or stones 

 along the sides, or, as an alternative, to arrange 

 half nine-inch pipes on two single rows of 

 bricks, running parallel to each other, and nine 

 inches apart, which answers fairly well (Fig. 5). 

 The pipes and bricks should be fastened with 

 cement ; this w^ill keep the earth very dry. It 

 is a great mistake, however, to make the earths 

 too elaborate, the simpler they are the sooner 

 the foxes wall take to them, and the more likely 

 they are to remain healthy and satisfactory. 



