VENTILATION. 



275 



a third kind of stove, in which are cultivated a section of plants which 

 for singularity of structure, elegance of flowering, and often a high 

 degree of the most dehghtful fragrance, is not approached by any plants 

 hitherto discovered. This structure is termed the Orchideous House, 

 the most complete specimens of which are those of Messrs. Loddiges, 

 Rollenson's, and Knight's, and we may add that, so far as our observation 

 has extended, they are the only commercial cultivators who appear rightly 

 to understand the cultivation of these extraordinary and at present 

 fashionable plants. It might appear invidious were we to pass over the 

 Clapton nursery without mention, as it is well known that the highly 

 respectable proprietor, Mr. Low, has been at great expense in sending out 

 collectors to enrich his own and facihtate the collections of private * 

 individuals. 



ON THE ERECTION OF STOVES FOR TROPICAL PLANTS. 



We have in another part of this work treated somewhat at large on the 

 subject of hot-house architecture : it remains only for us to state here that 

 structures intended for the cultivation of stove or tropical plants should be 

 rendered as close as possible by adopting the most approved modes of 

 glazing, by which means the cold air will be prevented from entering 

 the house in too great a quantity, and in consequence a vast economy in 

 the consumption of fuel will be the result. It should always be kept in 

 mind, that the smaller the quantity of fire heat applied to plants the 

 better, because the more it is used the more highly rarefied will the 

 air within the house become, and consequently the less fit for plants to 

 live in. 



VENTILATION. 



The degree of ventilation required in the stove is of much importance. 

 Puttying the laps, and having few openings or moveable lights, will 

 effectually exclude the cold and retain the warm air, admitting at the 

 same time a sufficiency of fresh for the plants, for air becomes lighter, 

 and has a tendency to ascend, when in a heated state, and to descend, 

 but much more rapidly, when in a cold state. Hence the top of a hot- 

 house is always the warmest, and for that reason flues, hot-water or 

 steam pipes ought alvrays to be placed as near to the floor as possible, 

 but so as to be clear of it. 



The nature of heated air being thus far imderstood, it follows that in 



T 2 



