82 



GARDEN WALLS. 



Fig. 58 is a plan of the upper course of 



Fig. 58. 



be 



the footing, show- 

 ing the manner 

 of bonding the 

 angles. The dot- 

 ted lines denote 

 the course above 

 of heading bricks 

 laid flat. The two 

 bricks on edge, 

 marked s s at the 

 reversed in every other 



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angle, will 

 course. 



Fig. 59 shows the elevation of a wall so 

 constructed. The advantages of Dearn's 

 hollow walls 



Fig. 59. 



are a saving 

 of one-third of 

 the number of 

 bricks, as 4500 

 are required 

 for a rod of 

 reducedbrick- 

 work, accord- 

 ing to the 

 usual mode 

 of building ; 

 whereas 3000 are sufficient according to 

 Dearn's plan. Nor is it only in bricks 

 that the saving is effected : half the mortar 

 will suffice, and the labour is just the same. 

 Fig. 60 exhibits the elevation, fig. 61 the 



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Fig. 60. 



Fig. 61. 



section, and fig. 62 the plan of another 

 mode of building hollow walls, recom- 

 mended by the same architect. Instead 

 of the brick-on- edge courses, half bricks 

 may be used as stretchers; and to pro- 

 vide these half 



Fig. 62. 



n 



hrhtT 



bricks economi- 

 cally, and with- 

 out the trouble of 

 cutting them with 

 the trowel, as is 

 usually done, he 

 proposes to cut 

 them half through 

 with a sharp knife, 



or piece of wire, while in a soft state, 

 prior to their being put into the kiln : 

 after burning they will separate easily 

 by giving them a slight stroke on the 

 part opposite to where they have been 

 already partially separated. This was a 

 great saving formerly ; for, had they been 

 moulded half brick size at first, they 

 would have been charged double duty, — 

 that is, each half brick would have been 

 charged the same as a whole one. In the 

 section, fig. 61, the three courses of foot- 

 ing are shown solid ; the elevation only 

 represents the wall above the footing or 

 ground-level. 



Hollow walls of 14 or 18 inches in 

 thickness may be constructed by running 

 up the sides of bricks, either on edge, or 

 better on bed, to the height of eight or 

 ten courses, and running a course of 

 headers through the wall, of bricks made 

 corresponding in length to the thickness 

 of the wall ; or these may be laid in 3 or 

 4 feet apart, and the course made good 

 with half-sized common bricks. 



Hollow stone walls. — Stone walls may 

 be built hollow, with a view to heat them, 

 either by causing the smoke and hot air 

 to circulate through them, or by hot 

 water in glass, earthenware, or metal 

 pipes. In constructing them, two long 

 2-inch planks are set on edge parallel to 

 each other, and kept separate to any dis- 

 tance by coupling screws. These are 

 placed in the centre of the intended wall, 

 and the sides are carried up in rubble, or 

 coursed stones, as high as the planks. 

 The screws are then slackened, which al- 

 lows the planks to come together, and so 

 be easily lifted up, and set for another 

 course. Headers, or stones sufficiently 

 long to go through the wall, are set in at 

 convenient distances, to bind the sides 

 together. The late Mr Loudon proposed, 

 in building hollow stone walls, to employ 

 a hollow light deal box, fig. 63, "3 inches 

 in thickness, 3 feet long, and 2 feet deep ; 



Fig. 63. this box to 



be used as 

 a gauge for 

 preserving 

 the vacuities 

 of the pro- 

 per width. 

 It has two rings in its upper side, by 

 which means it may be easily drawn up 

 to about two-thirds of its height, at which 



