A SIMPLE MODE OF HEATING GREEN-HOUSES. 



273 



piece, and a cement joint at G. H H, brick 

 work, surrounding the furnace, 4 inches 

 thick, (made tight by plastering both sides,) 

 except the front wall, which supports the 

 end of furnace ; this is 8-inch work. I I, 

 common stove pipe, leading to chimney at 

 such an angle as will prevent soot from 

 accumulating. J J, soot door for cleaning 

 the horizontal flue or smoke pipe. K K, 

 cast iron water tank, 20 inches wide, 4 feet 

 2 inches in length, and 5 inches deep, rest- 

 ing upon a projection in the brick work. 

 The length of the water pan, however, is 

 governed by the width of the air chamber 

 at M. N N N, sheet iron slides or covers, 

 resting upon the top of brick work, and by 

 moving these slides, the opening for the 

 hot air can be made of any width, or en- 

 tirely closed. O, a cast iron support for 

 the back end of stove, three-fourths of an 

 inch thick, standing on edge, which allows 

 the stove to expand in length or contract, 

 without displacing any part of the work. 

 The bottom of the air chamber is on a 

 level with the floor of the green-house. 



The stove and fixtures, placed in the 

 middle of, and not at the end of the house. 

 Two supply drains, P P, conduct the cold 

 air from both ends of the house ; these are 

 made of well seasoned plank, air tight, 16 

 nches square, and placed directly under 

 Vol. III. 18 



the plant ranges, four inches above the 

 floor. As they approach the furnace, they 

 are contracted in depth but increased in 

 width, till entering the air chamber, they 

 are nearly as wide as the length of the stove. 



The wood work of the supply drain only 

 reaches the brick work, which is here sup- 

 ported by an iron bar, with a single brick 

 under its centre, as a support. On the in- 

 side, within the air chamber, are small 

 piers of brick work, six inches high, extend- 

 ing nearly under the centre of the stove, on 

 the top of Avhich is placed two pieces of 

 sheet iron, that the cold air may be con- 

 ducted directly under the centre of the 

 stove. 



I think this plan, in some respects, pre- 

 ferable to the Polmaise. My supply drains 

 are kept upon the surface ; the air within 

 growing warmer as it approaches the fur- 

 nace, instead of getting colder, as in the 

 Polmaise plan, by descending so far be- 

 neath the surface, and away from the influ- 

 ence of the heated air of the house. 



If the air in the air-chamber, around the 

 stove and its pipe, becomes much heated, 

 as it does, it must rise if the slides, N N, 

 are drawn apart. This calls for a new 

 supply, which can only be furnished by the 

 drains. Every degree of heat that can be 

 retained in the air of the drain, as it ap- 



