so 
HISTORY OF BRITISH FERNS. 
glasSj acquire more than their natural delicacy of appear- 
ance. 
For the hardy FernSj the frame or case in which they 
are grown should have a northern aspect ; the eastern and 
western aspects are less favourable, though, with attention 
to shading during sunny weather, they may be adopted, 
and are at least much preferable to the southern, even with 
the advantage of shading. It is the heat, no less than the 
brightness of such an aspect, which is to be avoided ; and 
therefore, for all practical purposes, the nearer the situation 
in which they are grown approaches the northern aspect, 
the better. The plants must be kept cool in summer, by 
shading, by sprinkling, by moderate and cautious ventila- 
tion in the daytime, and by removing all impediments to a 
free circulation of air at night, not quite closing the frame, 
as just intimated, even by day. 
Wardian cases for Ferns, in which they may be planted 
out on rockwork, may be either of the size and nature of a 
small detached greenhouse, or of those window or balcony 
greenhouses made by enclosing within a projected sash a 
greater or smaller area external to the window ; or they 
may be of smaller size and more finished workmanship, 
for the interior of dwelling-rooms, for staircase-landings, 
