XVlll 
INTRODUCTION. 
and exactness, and would be better if double, and always 
one of them shut before tbe other is opened. 
Houses on a large scale can scarcely be made sufficiently 
air-tiglit to prevent the escape of aipeous exhalations : a 
leaden pipe, pierced with small holes, should therefore be 
carried round the building, at as great a height as may be 
found practicable, and this pipe connected with a reservoir, 
so that an artificial shower could be produced at pleasure ; 
if an increase of temperature were considered necessary, 
it might readily be attained by the introduction of hot- 
water pipes in the usual way. 
So great is the advantage of this plan, that the plants of 
tropical regions can now be cultivated in London with the 
most perfect success ; and, what is of still greater impor- 
tance, may be conveyed, uninjured by extremes of heat 
and cold, and without any additional supply of moisture, 
from the most distant parts of the earth. Mr. Ward, and 
Messrs. Loddiges of Hackney, have, in their glass cases, 
transmitted our plants to the most distant countries, and 
have received the same cases in return filled with valuable 
exotics, many of which have never previously reached this 
country in a living state. 
But the most pleasing character of this mode of cultiva- 
tion is, that it can be adapted to any spot that fancy may 
select : plants in this way may be grown in a drawing- 
room, without ever making the least litter or apparent un- 
tidiness, and without the trouble attendant on watering. 
If the cases were opened annually it would be sufficiently 
often, and the decayed fronds, or a too luxuriant growth, 
