452 



PITS AND FKAMES. 



in 2-feet lengths, one half of which is fixed 

 to the frame, while the other half moves 

 on a rail, so that when acted upon at one 

 end of the pit by a wheel and lever handle, 

 they may be drawn forward from one inch 

 to their whole length, as the extent of 

 ventilation may be less or more. A simi- 

 lar movement at the other end shuts them 

 up again. By these means the 4-inch open- 

 ings along both sides of the pit may remain 

 always open. Top ventilation is secured 

 through the ridge, as exemplified in va- 

 rious ways — vide section Ventilation. 



It is of great advantage to have free ac- 

 cess to pits of this kind during all seasons. 

 Here it is amply provided for along the 

 centre, and by having a door at both ends. 



Cold air is admitted at the sides close 

 to the ground-level, and also close to the 

 floor-level, by openings 4 inches square, 

 and at distances 4 feet apart. We prefer 

 small openings to large ones, as admitting 

 a more equal distribution of air ; and also 

 that they should be brought in at the 

 lowest part of the pit, to cause circulation. 

 The cold air admitted by them is received 

 into the space under the tanks, from 

 whence it is allowed to ascend upwards 

 between the tank and side walls to the 

 top, as well as through under them, and 

 ascending in the passage. The same 

 operation going on on the other side 

 causes an equal distribution of air in all 

 parts of the pits. 



Although the external openings for the 

 admission of cold air are placed 4 feet 

 asunder, it does not follow, nor is it requi- 

 site, particularly in winter, that many of 

 them be opened. All that is necessary is, 

 that an adequate supply be admitted, and 

 warmed sufficiently according to the sea- 

 son. In summer these precautions are 

 wholly unnecessary; for the whole of the 

 external, as well as the internal, openings 

 may be used at once. The spaces under 

 the tanks may be left solid ground, and 

 the tanks formed upon it, the passage only 

 being excavated, and the sides supported 

 by 9-inch walls. 



To render this pit still more efficient, 

 the whole interior should be excavated, as 

 shown in the figure, to the level of the 

 passage, and the tanks supported as we 

 have described. The spaces under the 

 tanks will be found exceedingly useful for 

 forcing rhubarb, sea-kale, chicory, mush- 

 rooms, asparagus, &c, and for keeping 



bulbs and other plants in during their 

 season of rest. 



This pit may be divided into four com- 

 partments of 25 feet each, the division 

 nearest the boiler being occupied with 

 French beans in winter and spring, and 

 cucumbers or melons during summer ; the 

 next with plants for flowering during 

 winter ; the third with strawberries, aspa- 

 ragus, &c. ; and the fourth with bedding 

 out plants. 



Fortune's plant-pit, fig. 633. — The trans- 

 verse section, as shown by the figure, will 



Fig. 633. 



fully explain the principle of this pit : a 

 back and front shelves or stages ; b pas- 

 sage along the middle ; c proposed tank. 

 The width is 9 feet, and will form a scale 

 to the other parts. The stages are of 

 narrow boards, laid on cross bearers, hav- 

 ing one end let into the walls, and the 

 other supported by upright posts set 

 along both sides of the walk. A narrow 

 shelf d, supported on iron brackets, runs 

 along the front, for small plants. These 

 brackets, Mr Fortune proposes, should 

 support the hot-water pipes ; but we 

 would suggest their being supported from 

 below, as being much less liable to strain 

 the front wall, which is only 9 inches thick. 

 Under the front stage a large water tank 

 is proposed at c, to contain the rain water 

 that falls on the roof. In regard to the 

 angle of elevation which plant-pits of 

 this description should have, Mr Fortune 

 quite agrees with our own experience on 

 the subject. "Any experience which I 

 have," he says, "goes to prove, that 

 houses with high angles — that is, from 

 30° upwards — having a wall behind, are 

 apt to draw the plants too much to the 

 front, and to make them one-sided • and 

 for this reason I prefer houses of this 

 description with rather flat roofs." The 

 angle Mr Fortune, therefore, prefers for 

 such houses, should range from 20° to 

 28°. The section of the pit above given 

 is rather below the minimum of these. 



