A CHAPTER ON GREEN-HOUSES. 



261 



the air-chamber to the open air through 

 the foundation wall, at 4, to supply the 

 house with fresh air. This air-pipe should 

 be six inches in diameter, and there should 

 be a slide iw it to enable us to shut it up, 

 whenever the weather is too cold to admit 

 of its being open, without lowering the 

 temperature of the house too much. 



Now let us suppose all is ready, and that 

 a fire is lighted in our air-tight stove. The 

 air in the air-chamber becoming heated, it 

 rises rapidly, and passes into the green- 

 house, through the grated opening at 1. 

 Very quickly, then, in order to supply 

 the deficiency caused in the air-cham- 

 ber, the air rushes through the cold-air 

 drain. This makes a current from the 

 coolest part of the house, at 2, towards the 

 air-chamber ; and, to make good again the 

 lost air carried off from that end of 

 the house, the warm stream, which rises 

 through the opening at 1, immediately 

 flows over the tops of the plants towards 

 the opposite end of the house, and, as it 

 becomes cold again, descends and enters 

 the mouth of the cold-air drain, at 2. By 

 taking advantage of this simple and beauti- 

 ful principle, — that is to say, the rising of 

 warm air, we are able in this way to heat 

 every part of the house alike, and have a 

 constant bland zephyr passing over the 

 plants.* 



It is not easy to find anything simpler, or 

 more easily managed, than this way of heat- 

 ing a small green-house. In this latitude, 

 a couple of cords of wood, or a couple of 

 tons of anthracite, will be sufficient for the 

 whole winter; for, it must be remembered, 

 that no matter how cold the day, the mo- 

 ment the sun shines, there is not the slight- 



* Our readers, to whom this mode of heating is not quite 

 clear, will please turn back to a detailed plan of the Pol- 

 maise mode, page 124, and also examine the plan of " A Sub- 

 scriber," in this number. 



We should add, that when a coal airtight stove is used, 

 there should be a water pan suspended over it. For a wood 

 air-tight, it is not necessary. 



est need of a fire ; the temperature will 

 then immediately begin to rise. Usually, 

 after bright days, which are abundant in 

 our coldest winter months, we shall not need 

 to light a fire till one, two, or sometimes 

 three hours after sun-set ; and if our air- 

 tight is one of good size, and constructed as 

 it should be, so as to maintain a good fire 

 for a long time, our last replenishing in the 

 evening need not usually be later than 10 

 o'clock ; but we must, in this case, give a 

 full supply of fuel for the night's consump- 

 tion. 



Every sensible person will, of course, use 

 light outside shutters, for the roof and side- 

 glass of such a house as this. We slide 

 them on at sunset, and take them off' at 

 sunrise ; and by this means, we not only 

 save one-third of our fuel, but keep up 

 a pleasant green-house temperature with- 

 out cold draughts at night. It is worth 

 while to remember, too, that in glazing 

 the roof, the most useful possible size for 

 the glass is 4-by-6 inches, or, at the largest, 

 6-by-8 inches. The former answers the 

 purpose perfectly, and is not only much less 

 costly than large glass, but is also far less 

 expensive to keep in repair; neither hail 

 nor frost breaking the small panes, as they 

 do the large ones. 



As to the minor details, we will have a 

 small cistern under the floor, into which 

 the water from the roof can be conveyed 

 for watering the plants. Beneath the cen- 

 tre stage, (which may be partly concealed 

 with lattice work,) we may keep our 

 dahlia roots, and a dozen other sorts of 

 half hardy plants for the summer border, 

 now dormant, and snugly packed quite out 

 of sight. 



We did intend, when we sat down, to 

 give our novices a great deal of exceed- 

 ingly valuable advice about the sorts of 

 plants that they ought to cultivate in this 



