148 
R us tic A dorn ments. 
always be at the command of the cultivator. To shade out excess of light 
and to close all ventilators is easy work enough, but if the house is so 
constructed that neither light nor air can obtain access in sufficient plenty, 
healthy vegetation will never be seen within it. As to the forms and 
dimensions of houses, and the uses to which they are to be put, the length 
of the proprietor’s purse must determine. The best possible house for all 
general purposes is one with a span roof (Fig. 2), the roof as low as possible 
to afford sufficient head-room and to accommodate the plants, with stages 
on each side and walk through the centre, and beneath the stages a sufficient 
service of hot-water pipes heated by a saddle or upright boiler. The lean-to 
form (Fig. 1) is admirably adapted for the utilization of a suitable wall; if 
the aspect is full south, a lean-to would 
answer admirably for vines, and almost 
all kinds of flowering plants : in a north 
aspect ferns would thrive; in east and 
west aspects camellias, oranges, and a 
number of valuable hard-wooded plants, 
such as heaths, epacrises, and azaleas. 
A safe angle for a roof is 45 deg., but 
low nearly flat roofs answer admirably 
for flowering plants in the case of span- 
roofed houses in open sunny positions, 
as we obtain thereby the immense advan¬ 
tage of having all the plants “ near the 
glass.” 
Next to the lean-to the three-quarter 
span (Fig. 3) is a most useful form of house. It is more especially adapted for 
erecting against walls that are not high enough to admit of a lean-to being 
built against them. It has also this advantage over the latter, namely: 
assuming it to be built against a south wall, it not only gets all the mid¬ 
day sun, but a portion of the morning and afternoon sun, too. Such a 
house is also more roomy than a lean-to, and therefore should have 
preference in the case of a low wall. Both lean-to and three-quarter span 
structures are not so difficult to heat as a span roof, because the back 
wall freely absorbs the solar heat, and thus by reflection warms the air of 
the house to a marked degree. 
The staging in greenhouses should be arranged in such a way that the 
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