346 



FORCING GARDEN. 



The roof is unequally ridged, the north or shorter side bo 

 ing slated and furnished with ventilators, to admit air. 

 The sashes are immovable, and the laps of the panes are 

 closely puttied. There is a path within, and a single turn 



Fig. 42. 



of a flue behind. We should prefer the following form, 

 in which there are ventilators, a a, and a hot-water appa 

 ratus surrounding the whole pit. The dimensions of this 



Fig. 43. 



may be fifty feet long, and nine feet wide, the glass being two 

 feet and a half from the curb of the bark pit in front, and 

 five feet behind. We next present a section of a pine-pit 

 with a curvilinear roof, in which the astragals are parallel. 

 A segment of an elliptical arch somewhat less than a quad 

 rant, the origin of the curve being on the front wall, seems 

 better adapted for a pit than any portion of a circle. Tbis 



