FORCING-PITS OR GREENHOUSES. 



87 



shows a greenhouse twenty feet wide by fifty feet long, 

 with furnace-room, or shed, ten by twenty feet. Here 

 the flues are so disposed as to avoid crossing the walkc, 

 being placed under the center bench, but as near as pos- 

 sible to the walk on each side, so that the heat may be 

 evenly diffused throughout. If a difference in tempera- 

 ture is required in a house of this kind, it may be obtained 

 by running a glass partition across the house, say at 

 twenty-five feet from the furnace end, which will, of 

 course, make the latter end the hottest. It will be 



Fig. 13. END-SECTION. 



observed that the plan (figure 12) shows by dotted lines 

 this new or revived plan of flue heating. Figure 13 (the 

 same scale) is a section, showing the arrangement of the 

 benches, etc. 



In constructing the furnace for flue heating, the size 

 of the furnace doors should be, for a greenhouse twenty 

 by fifty, about fourteen inches square, and the length of 

 the furnace bars thirty inches; the furnace should be 

 arched over, and the top of the inside of the arch should 

 be about twenty inches from the bars. The flue will 

 always "draw" better if slightly on the ascent through- 

 out its entire length. It should be elevated, in all cases, 

 from the ground on flags or bricks, so that its heat may 

 be given out on all sides. The inside measure of the 

 brick flue should not be less than eisrht bv fourteen 



