148 GREENHOUSE CONSTRUCTION AND HEATING. 
objections, such as (1) their liability to become overheated ; 
(2) the dust and dirt unavoidable where the stove has to 
be fed and cleaned inside the house, not to mention the 
risk of an occasional down-draught and its consequent 
deadly fumes ; and (3) even where the fire is carefully 
managed, and no over-heating occurs, the flue-pipe as well 
as the stove itself’ gives off a harsh, dry heat, which dries 
and parches the plants, and effectually prevents anything 
like healthy growth. Lastly, the heat being given off 
chiefly, if not entirely, at one point, a 
proper distribution is impossible. 
Stoves of the same type, but lined 
with fire-tiles or terra-cotta are much 
less objectionable than the last, but 
even these are not devoid of faults by 
any means. 
We now have to consider the 
little paraffin lamp-stoves so largely 
i} employed for heating small green- 
al houses, etc., in all parts of the country, 
and of which an illustration is given 
above (Fig. 96). These are merely 
oil-lamps on a large scale, with one or more broad wicks, 
and afford enough heat to warm small structures up 
to 8ft. or 10ft. long, by 5ft. or 6ft. wide, sufficiently to 
exclude frost. The weak points of this class of stove are 
(1) that the products of combustion escape directly into 
the atmosphere of the house, and this is of course 
anything but conducive to the health of the plants; 
(2) the unpleasant odour that generally arises from their 
use, and which clings to the house even when the stove 
