40 HORTICULTURE. 



Now we mean to heat our little green-house with an air-tight stove, 

 of good size ; and we mean to heat it, too, in the latest and most 

 approved system nothing less than what the English call Polmaise 

 by which we are able to warm every part of the house alike ; by 

 which we shall be able to create a continual circulation of the warm 

 air from one end of it, quite over the plants, to the other; and 

 which, no doubt, they will mistake for a West India current of air 

 every evening. 



In order to bring this about, we must have an air-chamber. This 

 also must be below the level of the green-house floor. It is not im- 

 portant under what part it is placed ; it may be built wherever it is 

 most convenient. In our plan (fig. 2), as there is a cellar under 

 the parlor, we will put it next the cellar wall, so that there may be 

 a door to enter it from this cellar. This air-chamber must be built 

 of brick, say about 7 or 8 feet square (as represented by the dotted 

 lines around b). The wall of this air-chamber should be two bricks 

 thick at the sides and one brick at the ends, and all smoothly plas- 

 tered on the inside. The top should be covered with large nagging 

 stones ; and upon the top of these, a course of bricks should be laid, 

 which will form part of the floor of the walk in the green-house 

 above. Or, if flagging is not to be had, then cover the whole with 

 a low arch of brick work. 



In this air-chamber we will place our air-tight stove, the smoke 

 pipe of which must be brought back into the cellar again, so as to be 

 carried into one of the chimney flues of the house. There must be 

 a large sheet-iron or cast-iron door to the air-chamber, to enable us 

 to feed the fire in the stove ; and, in the top or covering of the air- 

 chamber, directly in the middle of the walk (at 1), must be an 

 opening 1 8 inches in diameter, covered with a grating, or register. 

 Through this the hot air will rise into the house. 



Now, both that we may heat the house easily and quickly, and 

 a*so that we may have that continual circulation of air which is so 

 wholesome for the plants, we must also have what is called a " cold- 

 ah drain ; " it must lead from that end of the house farthest from 

 the hot-air chamber, and therefore the coldest end, directly to the bot- 

 tom of the air-chamber itself. We will put the mouth of this drain in 

 the middle of the walk near the door, at 2, with a grating over it 



