130 GREENHOUSE CONSTRUCTION AND HEATING. 
or the temperature inside will be liable to rise to an 
injuriously high point under the influence of bright sun- 
shine. To a certain extent air may be given, in mild 
weather, by sliding the front lights along so as to leave 
a small aperture between each, but with a cold wind blowing 
a little top ventilation only should be given. This may 
be provided by fixing a square of glass here and there in 
a small sash or frame, hung at the back and made to open 
with a casement stay or the like, or by leaving a narrow 
aperture all along 
either at the back of 
the coping, against the 
wall, or beneath its 
front edge, above the 
front lights, these being 
closed with narrow 
wooden flaps, with. 
hinges, to be opened 
and closed at will. 
Conservatories.— 
The real meaning of 
the word conservatory 
is a house (or place) in 
which to preserve, or keep, plants, as distinguished from a 
structure intended for growing purposes only. A conser- 
vatory may consequently be of any size, from quite a tiny 
affair, only a few feet square, to the enormous structure at 
Chatsworth, which covers an acre of ground, and may be 
built in any style, from the plainest lean-to to an elaborate 
structure with a lofty curvilinear or otherwise ornamental 
roof, cusps to the side-lights, coloured glass, cast or 
