GREENHOUSE STRUCTURES. 85 



have but one greenhouse. It will be necessary to have 

 the flues built as close to the walks as possible, so that 

 the heat maybe evenly distributed in the two outside 

 houses. The cost of three greenhouses, each eleven by 

 sixty feet, connected as shown on the plan, heated by 

 flues, would be about $600 at present prices in this 

 locality. Figure 21 shows a greenhouse twenty feet wide 

 by sixty feet long, with furnace-room, or shed, twelve by 

 twenty feet. Here again the flues are so disposed as to 

 avoid crossing the walks, being placed under the center 

 bench, but as near as possible to the walk on each side, 



Fig. 21. PLAN OP A. SINGLE HOUSE. 60x20 ft. 



F, R, Furnace Room, 12x20 ft.; B, B, Side Benches, ft. wide; C, C, Cen- 

 ter Bench, 8ft. wide; W, W, Walks, 2ft. wide; S, S, Smoke- 

 flue; C F, Furnace, with Chimney above. 



so that the heat may be evenly diffused throughout. This 

 is our favorite style of greenhouse to heat by a flue, and 

 such as is now mostly used by beginners ; it would, in this 

 locality, at present prices, if built of wood, cost about $400. 

 If a difference in temperature 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 that end the hottest. 

 It will be seen that the principle set forth in my article of 

 November, 1874, is carried out in both these plans, and it 

 would be unsafe to attempt to heat greenhouses of these di- 

 mensions without conforming to it. Its peculiarity consists 

 in running the flue, in each case, back to the furnace 

 from which it starts and in to the chimney, whici> i 



