THE FERN HOUSE. 107 
can grow Ferns well, witbout much fire-heat, or none at 
all during the summer. It looks expensive to double 
glaze, but I am prepared to show that, on my plan of 
‘double glazing,’ it is no more so than single glazing 
as a rule. 
A fernery needs very little or no ventilation, except 
when it is built facing the sun: then some top ventila- 
tion is necessary for the summer, but none from Sep- 
tember till April. Ifthe roof is double glazed with clips 
on the fixed vertical bar, and with green glass or the 
top painted with semi-transparent paint laid on with a 
large brush, very little trouble will arise in growing Ferns 
successfully. They will, under these circumstances, 
- maintain a very even character, being attended by a 
constant and equal temperature, which is the very thing 
forthem. During the winter months a few cinders or a 
little coke should be put into a proper stove to keep 
up a healthy temperature, when the most delicate classes 
may be grown successfully. If the fernery has to be 
built facing the south, be careful not to have the angle 
of the roof of too sharp a pitch: an angle of 30° is 
quite enough for such an aspect, but for a northern or 
north-western one, an angle of 32° may be adopted, as 
no sun can then get at the plants to affect them. If the 
fernery is facing the north, it may be double glazed with 
Belgium green glass or with common white, but it will 
be found that they will do much better under green 
glass than under white. 
It is necessary for trade purposes to stimulate ferns 
as much as possible to keep up successional fronds for 
cutting or for plants to supply customers. To do this, 
different departments connected with Fern culture are 
required ; one not too hot, for large specimens from 
