60 
CONSERVATIVE 'WALLS. 
In addition to the various erections long devoted to the cultivation of flowering 
exotics, a new one has, within the last few years, been brought into notice, which 
has obtained the name of a conservative wall. Adopting this as an appropriate 
appellation, we intend here explaining what are its principal features and uses, and 
afterwards supplying a design which we think involves a material improvement on 
former .methods of constructing such objects. 
Conservative walls are those of an ornamental character, erected in pleasure- 
grounds, and furnished with flues, or other means of conveying artificial heat to the 
plants grown on them, as well as facilities for covering the latter externally during 
cold weather. They may, however, be without any arrangement for receiving 
fire-heat, and be simply provided with some adequate protection on the outside ; 
but in this case, only half-hardy plants can be cultivated, and not the more tender 
greenhouse species. 
The purport of all such walls is to afford the means of growing those greenhouse 
plants that can be attached to a flat surface, without the cost of erecting and main- 
taining a greenhouse, and, at the same time, to add a most delighful feature to a 
pleasure-garden, and exhibit the gratifying spectacle of delicate exotics flourishing 
arid blooming with more than their usual vigour in the open air throughout the 
summer. 
For the attainment of the ends just specified, several circumstances have to be 
taken into account. Convenience and propriety suggest that the wall should be as 
near as possible to the boundary of the pleasure-garden ; for if reared near the 
middle, or at any distance from the outside, it will not only be difficult to convey 
fuel to it, and to conceal its northern side, but it will appear objectless, and decidedly 
out of place. A plain wall is nowhere tolerable save when it defines the limits of 
an estate, or of a particular department. And perhaps the fittest situation for a 
conservative wall is between the pleasure-grounds and kitchen -garden, or in that 
part of the former which is contiguous to the offices. In either of these positions, 
it will form an agreeable line of separation. 
But it is of chief importance that the aspect of the wall be attended to, whatever 
else may be disregarded ; and unless the spot between the portions above mentioned 
•offer an exposed front to the south or south-west, some other must be selected. In 
most villas, or small mansions, a line of wall, architecturally finished, and carried 
along in direct connexion with the house, before the offices, may be readily obtained^ 
and would be a desirable appendage to a residence, while it served to conceal the 
meaner parts of the building. 
With very few exceptions, wherever conservatory walls exist they have been 
erected as mere boundary fences, and covered with ornamental plants solely with 
