HEATED BY FERMENTATION. 



437 



high as the bottom of the coping-stone, 

 to prevent the weather from acting upon 

 any part of the walls of the pits." The 

 authority just quoted highly approves of 

 pits, heated by hot dung or other fer- 

 menting matter, being placed parallel and 

 near to each other, so that the back lin- 

 ings of the one may serve for the front 

 linings of that which is immediately be- 

 hind it. 



The following description of a cucum- 

 ber or melon pit is by an anonymous 

 contributor to "The Gardeners' Maga- 

 zine," who very properly recommends, 

 where the ground is liable to be flooded, 

 to sink the foundations only to the depth 

 of 12 or 15 inches under the surface, and 

 to lay a drain along the centre of brick 

 on edge, and covered with bricks laid 

 across ; but in ordinary high and dry 

 situations they should always be sunk 2 

 or 3 feet below the surface, and a cavity 

 cut that depth for the linings, for the 

 better retaining the heat, and for conve- 

 nience in working. This pit is 2 feet 6 

 inches below the ground-level. "The 

 front and back walls are built in the 

 pigeon-hole manner, and a vacuity is left 

 between them and the brick-on-edge divi- 

 sions. A stone shelf may be placed over 

 the vacuity at the back part, for holding 

 strawberries in fruit, &c. The lights are 

 at an angle of 12° to the horizon." We 

 think this pit would be much improved 

 by substituting slate for the brick be- 

 tween the bed and vacuity, as in Atkin- 

 son's pit, already described. 



Atkinson's succession pine pit. — These in 

 many respects resemble the early and 

 late forcing pits of the same architect, 

 already noticed. The walls are built in 

 the pigeon-hole fashion, having an inner 

 4-inch wall carried up to within 2 feet of 

 the top, leaving a space between each 

 which is covered at top with a thin slate, 

 with holes in it to admit the steam from 

 the back linings into the atmosphere of 

 the pit. The steam is regulated by plugs 

 in the slate, and the walls are tied together 

 by 14-inch piers 4 feet apart, intended to 

 strengthen the walls and support the 

 rafters which are placed over the centre 

 of each pier. The front wall is in 

 like manner hollow, and also supported 

 by similar piers, the cavity between the 

 walls in this case being left open. The 

 front wall is divided into panels fitted 



with thin tiles set on edge in cement, so 

 that the heat of the linings may freely 

 pass through into the cavity, and ascend 

 through it, and warm the atmosphere of 

 the pit. This precaution of excluding 

 the rank steam from the linings from 

 entering directly into the pit, particu- 

 larly during winter, has its advantages. 

 The dimensions of these pits are as fol- 

 lows : 6 feet 9 inches in the clear of the 

 interior walls in width, the back wall 



8 feet high, the front one 5 feet ; the pit 

 is sunk 3 feet under the ground-level, 

 surrounded by trenches for the linings 

 2i feet wide. The retaining walls are 



9 inches thick, coped with oak kerbs 

 1 foot in breadth. 



Cooper's pit for forcing grapes hy dung 

 heat, fig. 607. — This plan was communi- 



cated to the Horticultural Society by 

 Sir George Staunton, as the practice of 

 the Rev. Blakley Cooper, and has merits 

 to claim some attention even at this day. 

 Mr Cooper states his reason for adopting 

 this plan in the following words : " I have 

 long thought it unnatural to force the 

 branches of a vine in a heated atmosphere, 

 whilst the roots are confined to a soil 

 that, early in the season especially, is, if 

 not frozen, the very reverse of hot ; and 

 I have presumed it to be impossible that 

 the roots could keep pace in their growth 

 with the branches, and consequently 

 maintain that supply of sap required of 

 them by the forced and accelerated ad- 

 vance of the shoots. It is well known 

 that a cautious and progressive tempera- 

 ture in the house can alone insure success 

 in bringing out all the eyes ; and that in 

 most cases, when early forcing is resorted 

 to, a few eyes only on each shoot can 



