94 THE HOT-HOUSE. [Jan. 
is to be made of iron-bars, and one half of the depth of the fur- 
nace; the brick for the furnace should be laid in good well-worked 
brick-clay (not in mortar), which, when burned by the fire, will 
cement so as to become a solid mass; this must have an iron-barred 
grate one half of the depth of the furnace, as before observed, the 
remainder of the depth to be made solid with brick; having an ash- 
hole underneath, with a close-shutting door to it. The furnace must 
also have an iron door placed in an iron frame, which door must be 
furnished, near the lower part, with another small door, for the ad- 
mission of air to the fires, both having latches, so as to shut close 
occasionally; observing that this door is not to be wider than what is 
necessary for the admission of the fire-wood. Having both your 
ash-hole and furnace thus provided with close-shutting doors, you 
may manage your fires to great advantage, by closing them up oc- 
casionally from too great a current of air, especially when burned 
clear, which would carry off the heat through the flues too rapidly. 
If you intend to burn stone-coal, the furnace need not be so large, 
but the grate must run the whole depth. 
Having finished the furnace, proceed to carry up the walls, ob- 
serving particularly, to leave a scarcement a foot wide in both end 
•walls; immediately opposite, where the back wall flues are to be 
erected, from the level of the lowest flue to the top of the highest, 
by which means you can open the ends of the flues and clean them, 
■when necessary, either by running in scrapers on the ends of long 
poles, or hauling any kind of small brush-wood through them, by 
means of aline from one end to the other; these scarcements may 
either be made up with brick from time to time, or with sashes and 
shutters, which will be more convenient. Whenever there are re- 
turned flues, one above the other, similar contrivances will be found 
useful; but where there is only one running flue, a top tile may be 
taken off at convenient distances, by which means it can be cleaned. 
When the walls are finished, then begin to erect the flues along 
the inside walls; but, as before mentioned, it would be adviseable to 
have them detached therefrom two or three inches, that, by being 
thus apart, the whole heat may arise from both sides of the said 
flues, which will aff'ord an additional advantage, in moie eff'ectually 
diff'using the whole heat internally in the house; much of which 
would be lost in the back wall were the flues attached to it: the first 
range may be carried along the front and both ends, dipping under 
the end door-ways and rising the other side; if there is no return 
flue to be in front, which is not necessary in a house of moderate 
dimensions, let this flue be carried so that the covering tiles and 
plaster may be within three inches of the level of the front and 
end walls, upon which a board may be supported with bricks, to be 
brought on an exact level with the front wall, for the convenience of 
placing thereon a number of pots of strawberries, for forcing, or any 
other small plants; and, moreover, the flue being carried near the 
glasses, the heat will be particularly efficacious in repelling the cold 
external air, frost, damps, Sec. and also in distributing the heat more 
equally to all parts of the house: for the several returns in the 
