PITS HEATED BY HOT WATER, Ac. 



457 



made to open. The hot-water pipes are 

 supported upon suspended brackets, a 

 mode very generally adopted at 

 Frogmore, which has the advan- 

 tage of their being less likely to 

 get out of level than if laid upon 

 piers, which, on soft foundations, 

 are apt to sink. Being suspended as here 

 shown, the pipes lose none of their heat by 

 abstraction, but give it out from all parts 

 of their surface by radiation. The floors 

 are laid with polished pavement. For 

 cultural purposes no houses on the lean- 

 to principle are better adapted, and the 

 healthy condition of the plants gives 

 efficient evidence of this. 



Ridge-and-furrow roofs were first em- 

 ployed by Sir Joseph 

 Paxtonfor roofing pits. 

 Of the correctness of 

 the idea there can be 

 no doubt. The an- 

 nexed diagrams will 

 explain his views, 

 which are given in 

 answer to a corre- 

 spondent in " The 

 Gardeners' Chronicle." 

 He says, "The best 

 method of building 

 pits is to construct 

 them of 9-inch brick 

 on bed ; and the best 

 mode of heating them is by Roger's 

 conical boiler." In the case of a pit 

 78 feet long and 7 feet wide, he ad- 

 vises as follows : — " Cover the pit with a 

 ridge-and-furrow roof, making the space 

 from the ground in front of the pit to the 

 valley-rafter 3 feet 6 inches, and the back 

 Fig 643 wa ^ below the 



rafter 5 feet 6 

 inches. See sec- 

 tion across the 

 pit," fig. 643.— 

 " Divide the 

 whole length 

 into four com- 

 partments for 

 growing the different sorts of plants, by 

 4i-inch brick-on-bed walls. Divide the 

 whole length of the ridge-and-furrow roof 

 into 12 bays, having a ventilation in the 

 angle of each pediment, as at d d d, fig. 

 644. Now, to get to the plants, each 

 light is hinged at the valley-rafter, and 

 fastened with a thumb button at the 



VOL. I. 



ridge-rafter. By referring to fig. 644, 

 it will be seen that the light or frame 

 « h Fig. 644. 



leaves the ridge rafter at a, in the direc- 

 tion of b, and lies flat upon the next light 

 at c. Each light may be opened in this 

 way, so that a workman may get to any 

 part of the pit." 



A pit upon this construction was erected 

 in 1842 by John Allcard, Esq., of Strat- 

 ford Green, well known for his enthusi- 

 astic love of plants. A description 

 of it, with the annexed illustrations, is 



Fig. 645. 



published in " The Gardeners' Chronicle." 

 " Each ridge is formed of two lights rest- 

 ing on the top sides, where they open 

 against each other, and secured on the 

 lower sides by hinges ; so that when it is 

 necessary to give air, or to work in the 

 interior of the pit, they can be tilted to 

 any required height, or be thrown back 

 like the leaves of a book, against the 

 ridges on either side. In wet weather 

 these top lights can be kept quite closed, 

 as abundance of air can be admitted both 

 at the back and front of the pit by means 

 of triangular ventilators situated immedi- 

 ately under each ridge. All the water 

 which falls on the pit is carried off in 

 gutters formed in the rafters, upon which 

 the lower sides of the ridges rest." The 

 dimensions of Mr Allcard's pit are 40 feet 

 long, 9^ wide, and 5\ feet deep at the back, 

 and 4 feet in front. The following de- 

 scription refers to the figures annexed : 

 " Fig. 645, a, represents a light open, with 

 the iron stay pierced with holes to regu- 



3 m 



