CONSTRUCTION OF GARDEN WALLS. 



97 



Fig. 92. 



fact, none of the objections so common to 

 the Yorkshire paving, or any other free- 

 stone, seem to apply to the Castlehill 

 Caithness paving. 



Mr R. Mallet of Dublin, an architect of 

 great taste and ingenuity, has recom- 

 mended, in the " Gardeners' Magazine," 

 vol. ix. p. 193, the use of slate walls for 

 garden purposes. He proposes to em- 

 ploy cast-iron uprights, the spaces be- 

 tween being filled in with 

 slabs of slate. The section 

 of these uprights to be as in 

 fig. 92 : they are to be placed 

 in the plane of the wall, and 

 supported by being set on 

 ^ _ blocks of stone in the foun- 

 dations. " When slates, 

 boards, or flags are used, the breadth of 

 the rebate in the iron post may be consi- 

 derably less — say an inch, as in 

 fig. 93. Slate ' walls,' of great 

 strength and durability, might 

 be made by filling up the 

 spaces with two surfaces of 

 slate, distant three or four 

 inches, with gravel and grout, 

 or rammed puddle, as in fig. 94, in which 

 a is the iron upright, b the slates, 



Fig. 94. 



and c the puddle or filling-up matter. 

 Slates thus placed, from the inertia 

 and non-elasticity of the mass, would 

 almost resist fracture ; a blow of a ham- 

 mer would only punch a hole through, 

 without shattering the slate." Or they 

 may be left hollow ; but we question if 

 they could be heated with safety. Slate 

 walls made in the way recommended by 

 Mr Mallet, "with the addition of eyes 

 cast on one side of the iron uprights for 

 the wires of a trellis, and the slates 

 painted black, would appear to be," he 

 thinks, " the best garden walls that could 

 be erected. They could harbour no in- 

 sects, would not be eaten out by nailing, 

 would look better than brick walls, and 

 the tops of the uprights would be available 

 for rolling blinds, &c, for protection. Per- 



VOL. I. 



haps the deep violet colour of the slates 

 would be the best possible for garden 

 walls, which " he has " deduced from 

 some recent observations on the rays of 

 light and heat. These slate walls might 

 be hollow — viz., filled with rounded peb- 

 bles, and no- 

 ly 1 * thing else, and 



thus be heated 

 by steam occa- 

 sionally, or be 

 entirely hollow, 

 with a double 

 rebate, and per- 

 forated upright- 

 ly, and become 

 long smoke flues 

 of great depth 

 and thinness, 

 as in fig. 95, in 

 which d is the 

 side view of an 

 upright, and e a 

 cross section or 

 plan." 



Such walls would be both economical 

 and useful, and certainly far more elegant 

 than those in common use. We differ, 

 however, in opinion from Mr Mallet, in 

 regarding them as capable of being heated 

 more especially by flues, as the slates 

 would not stand the heat near the fur- 

 naces; and as for jointing them with tar, 

 as he proposes, to prevent the escape of 

 smoke or steam, we consider it the very 

 worst material that could be employed 

 for that purpose. 



The same intelligent architect has also 

 suggested, in the work last quoted, a brick 

 wall supported with iron uprights, and 



the spaces 

 filled in 

 with reba- 



ted bricks, 

 as shown 

 in annex- 

 ed fig. 96. 

 "A 4-inch 

 wall built 

 in this 

 way, with 



posts at every 4 feet," Mr Mallet thinks, 

 "would be as strong and stiff as an or- 

 dinary 14-inch wall, and, excluding the 

 original expense of brickmaking and 

 foundry apparatus, would not cost above 

 one-third of the expense. The bottom 



Fig. 96. 



