COMBINED CELLAR A^D GEEEKHOUSE. 101 



in fig. 47. If the glass roof is made fixed it should have 

 ventilating sashes 3x3, at intervals of six or nine feet on 

 each side of the roof ; if of sashes, they should be seven 

 feet long by three feet wide, every alternate one being 

 arranged to move for ventilation in the usual way. The 

 position of the structure would be best with its ends north 



Fig. 47. — GREEXHOUSE A2sD CELLAR COMESED. 



and south. The shutters for covering the glass at night 

 should be made of light half-inch pine boards, three feet 

 wide by seven feet long. 



It will be understood that the advantage of this com- 

 bination of cellar and greenhouse over the ordinary cold 

 pit is that the air of the greenhouse is warmed or equal- 

 ized by mixing with the atmosphere of the cellar, which 

 will rarely be less than 40°. For the same reason, if a 

 high temperature by fire heat were wanted, say 70°, this 

 large body of air from below of 40° would make it diffi- 

 cult to obtain it. It will be necessary, of course, to have 

 the flooring boards covering the cellar wide enough apart 

 to freely allow the passage of the air; this will at the same 

 time give light enough for any operations necessary to be 

 done in the cellar. 



