WALLS, FORM OF. 



552 



WALLS, FORM OF. 



that many will still insist upon doing so ; 

 and therefore the best description of walls, 

 most approved methods of protection, &c., 

 continue to be subjects of the first im- 

 portance. No material for kitchen-garden 

 walls can equal good red brick of medium 

 hardness of texture. The joints should 

 be formed as narrow as possible, of the 



FIG. I. CURVED FORM FOR FOUR-AND-A-HALF- 

 INCH WALL. 



best lime and sharp sand, and can either 

 be left white, or the lime can be coloured 

 a few shades lighter than the bricks. The 

 bricks are better without any colouring 

 whatever. This is not only the best- 

 looking wall, but the plants are easier 

 trained to it, and are probably subject to 

 fewer alterations of temperature upon its 

 surface than they would be upon a wall 

 of any other substance or colour. Walls 

 should never be less than 8 or more than 

 14 feet high, and may vary from 9 to 22 

 inches in thickness. From 10 to 12 feet 

 is a good average height, and 14 inches in 

 thickness will impart strength enough for 

 that height, but when they are built in this 

 thickness, a quasi buttress, 9 inches thick, 

 is placed at intervals of 10 or 12 feet, to 

 give stability to the wall. The super- 

 structure is carried up on the foundation 

 in the thickness of 9 inches to the level 

 of the ground, or a few inches above it, 

 and a coping of one or two courses laid 

 in the ordinary way, and a third course 

 of headers placed on the side, is used to 

 finish the wall, giving it the appearance 

 of being built in panels. When built 

 without piers or buttresses, the wall is 

 frequently built in a curved form, as 

 shown in Fig. I, as a 4! inch curved 

 wall of this form will resist as much 

 pressure as a straight wall 9 inches thick 



kitchen-garden walls should be straight; 

 and they are not safe without piers, unless 

 they are a brick and a half, or 13^ inches, 

 thick. 



Copings. All walls for fruit-trees should 

 also be furnished with a coping of stone, 

 slate, or some other hard, durable material, 

 of sufficient width to project 4 inches on 

 each side of the wall. The top of the 

 coping should be slightly convex, and the 

 under surface as much concave, to facili- 

 tate the removal of water. A groove or 

 " throating " should also be formed 

 inch deep, and f inch from the out- 

 side edge of the lower side, to inter- 

 cept and throw off all drip. The 

 coping should also be made in lengths as 

 long as possible, to reduce the number of 

 jointings. If stone is used, the joints 

 should be formed of the best Portland 

 cement ; if slate, a mixture of white and 

 red lead must be used. It would also be 

 advisable to have the copings overlap, as 

 shown in Fig. 2, as they are compara 

 lively useless unless waterproof. As if 

 fine weather frost falls in nearly perpen 

 dicular or vertical lines, a coping pro 

 jecting over a wall will often protect th 



FIG. 2. COPING REBATED TO OVERLAP. 



trees on its surface ; and it will do this 

 the more effectually if it has previously 

 preserved them in a dry state. Permanent 

 and temporary copings of much greater 

 width than 4 inches are frequently used. 

 Temporary copings of much greater 

 widths are frequently used. The section 

 in Fig. 3 represents a bracket for sup- 

 porting a wide coping of slate or other 

 material that is sometimes brought into 

 temporary use. The top surface, A, of 

 the bracket consists of a bar of iron 2 

 inches wide, on which the slabs meet. 



without piers. As a rule, however, all j Any length of slate may be used, but 



