Jan.] the GREEN-HOUSE. §7 
commonly made of good timber from six to eight or ten inches 
thick, according to their height, so as to admit as great a portion 
of light and heat of the sun as may be; and, on the same account, 
one half or one third of the roof is formed of glass-work, made in 
the manner of hot-bed lights, the remainder being either covered 
with slate or shingles and tarpaulins. Or very strong canvass fixed 
on rollers, to be let down over the roof-glasses in very severe 
weather; you may also have large canvass cloths upon rollers to 
let down occasionally before the windows, or in default of such, 
you may nail up garden mats. 
Let one-third of the front side of the roof, for the whole length 
of the house, be formed of glass-work, and the back wall raised, so 
as that a horizontal ceiling may be carried from the upper part of 
these lights to it, which will cause the back half of the roof to be 
somewhat more flat than the front. Ornamental wood-work may 
be erected outside along the top of those lights to give a light 
appearance to the roof. Or, if the house be small, you may carry 
the entire roof with a gentle slope from the front to the back wall, 
which must be made of a proper height for that purpose; one-third 
or one-half of such roof may be made of glass-work, from the ter- 
mination of which carry the ceiling on a level to the back part of 
the house. 
The better to confine the air warmed by the sun in the day time, 
and to prevent the cold air from rushing in on the approach of 
night, when that within begins to cool, and consequently to con- 
tract in bulk, I would advise to have all the panes in the roof- 
lights neatly and closely puttied where they overlap one another; 
and to have either one, two or three of those lights, in proportion to 
the length of the house, so constructed, as to slide down and up a few 
feet by means of pulleys, in order to give vent to the foul air gene- 
rated in the house, which naturally ascends to the upper part. The 
sized glass, recommended in page 11, for hot-bed lights, is what I 
would particularly recommend for these roof lights, being not only 
the strongest but by much the cheapest. 
The windows or upright front-lights must be made with large 
panes of glass, &c. to admit the more light, as well as to give a 
handsome appearance to the house; the upper half of each window 
must be so contrived as to slide down, and the lower half up occa- 
sionally, to admit air to the plants when necessary. 
If a spacious and ornamental window be placed in each end, (if 
the house be detached) to receive the benefit of the rising and set- 
ting sun, it will be of considerable advantage; these particularly 
should have good close shutters either inside or outside, and be 
kept shut every night during the winter, and also in the day time 
in very severe weather, except while the sun immediately shines 
on them. If the front is so contrived that inside shutters to the 
windows cannot be conveniently hung, outside sliding shutters 
should be made to be used only when necessity requires. 
But let it be particularly observed, that all the lights, cases, 
doors, and wood-work of the house be made of good seasoned 
wood, and well painted, to prevent either their swelling by wet or 
