CONSERVATORY WALLS. 
85 
causes which affect the vitality of vegetation, we will not pre- 
tend to determine. 
To inure an exotic to the rigours and changes of our seasons 
requires some considerable time and preparation; it is not 
reasonable to suppose a plant can in one or two years so change 
its constitutional habit as to withstand uninjured either the one 
or the other, for it may be that the periods of excitement and 
rest natural to it are directly opposed to our seasons; so that 
to affect this, the first and most material alteration in the cha¬ 
racter of the plant, time is the principal agent. In most cases 
it may be forwarded a good deal by employing a medium po¬ 
sition for the first exposure, that is such a situation in which 
only part of the severities may be felt; and it is this which 
creates the value of conservatory walls : standing out in this 
manner, with properly constructed screens and other means of 
protection, the plant enjoys through the growing season an 
abundant supply of food ; and if managed so as to be allowed 
the necessary time to elaborate and mature its acquired secre¬ 
tions, there will be but little danger of its receiving any mate¬ 
rial damage through the winter season. The construction of 
these walls must be determined in a great measure by the 
description of plants intended to place against them. For many 
of the finer sorts of greenhouse plants it is necessary that flues 
be added, and indeed a glazed front; but as this is an expensive 
erection, and we are not now writing for those who can employ 
an architect, we will reduce the scale of our ideas, and suppose 
a wall to be standing, rather an unsightly object perhaps, and 
which it is desirable to cover; we will suppose also that Camel¬ 
lias form a principal part of the subjects intended to plant 
against it, (if deciduous shrubs are used it will be much easier;) 
the situation should be one facing to the south-east or the south¬ 
west. either of which is preferable to due south. The first pro¬ 
ceeding will be to prepare the border : the natural earth, unless 
very good, should be removed to the depth of about two feet 
and a half, a third of the excavation should be filled up with 
stones and brick rubbish, to drain oft superfluous moisture , 
this is the most important part of the whole, for if the bed is not 
thoroughly cleared of any excess of moisture, all other endea¬ 
vours will fail. On these stones a thin turf may be laid all over, 
to prevent the earth falling between them. A mixture of loam 
