CHAPTER X. 



FORCING PITS OR GREEN-HOUSES. 



Forcing pits and green-liouscs of the style about to be 

 described, whenever the greater expense in their erection 

 is not a consideration, are, in our experience, far superior, 

 and in the course of five or six years, more economical for 

 all purposes of forcing or forwarding vegetables, than the 

 hot-bed or cold frame. Figure 23 represents the end sec- 

 tion aud ground plan of the style we have in use, and 

 which may be adapted to any plant that requires artificial 

 heat and protection of glass. The pits, represented by 

 this plan, are 100 feet in length, and each 11 feet wide in- 

 side. The heating is accomplished by one of Hitching's 

 Patent Boilers, ( C), heating about 1200 feet of 4-inch pipe. 

 The glass roof, (J7), is formed of portable sashes, 6^3 feet ; 

 each alternate sash is screwed down, the others being 

 movable, so as to give abundance of air. The fixed roof 

 plan of building green-houses or pits, is, in our climate, a 

 great mistake, in my opinion, unless in large graperies 

 or conservatories, where architectural beauty is of more 

 consideration than the health of the plants. The mov- 

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