362 



FORCING GARDEN. 



40. 



The succession-pit performs the same functions as the 

 nursing-pit, but at a more advanced stage of the growth 

 of the plant, and consequently requires an increase of 

 size. With this difference, At- 

 kinson's Melon-pit does very 

 well for summer use. In colder 

 seasons, we should prefer a pit 

 similar to that represented on 

 the margin ; in which a hot-wa- 

 ter apparatus on the siphon 

 principle is employed to heat 

 the atmosphere of the pits, and 

 the bottom-heat is communicat- 

 ed by the circulation of hot wa- 

 ter from the same boiler, in open 

 troughs resting on the bottom of 

 . the pit. The boiler a is placed 

 nearly on a level with the bot- 

 tom of the pit. 5, Pipes, on the 

 siphon principle for warming 

 the air of the pit. CC, Troughs 

 for communicating the bottom- 

 heat-, placed in the bottom of the 

 pit on a level with the boiler. 

 The water is drawn from the 

 boiler to the ends of the troughs 

 d d by small movable siphons, 

 which promote its ciiX5ulation. 

 The bed j?^ in which the plants are plunge-d, is supported 

 by, a framework of woo<:l, resting- on brick piers between 

 the troughs. A ]x)iler placed in the centre is sufficient 

 for a -range of sixty feet. Pits sueh as these have been 

 in successful operation for the last two years in the gar- 



