156 Management of Hothouse Flues. 



makers avail themselves of the information afforded by Dr. 

 Anderson, Count Rumford, and other later writers, and let 

 them so contrive their works, that they may be opened and 

 closed at pleasure, and the most weighty objections of the 

 new school to open fire-places will be obviated. Then may we 

 expect that proposals for introducing streams of warm air 

 (without at once giving up the occasional enjoyment of radiant 

 heat from an open grate) will be favourably received by a 

 numerous and enlightened class of persons. 



In adwelling-house recently erected here, I have, besides open 

 grates, introduced an apparatus by Mr. Boyce, author of " Re- 

 marks of the different Systems of "warming and ventilating Build- 

 ings, 1826." This apparatus is so contrived, that the masses of 

 heated matter between which the air is made to pass, retain, 

 like a common oven, a high degree of heat for many hours 

 after the fire is extinguished, so that any close building, warmed 

 by it in the day, undergoes but little change of temperature 

 during the night; indeed, on the following morning, streams 

 of warm air continue to flow in through the valves provided 

 for that purpose. 



The plan is very simple, and its effect powerful beyond con- 

 ception. Nothing appears to me so well adapted to the heat- 

 ing of hot-houses. No night-watching with it would be 

 necessary ; and little or no danger from negligence need be 

 apprehended. 



I am aware that Mr. Tredgold, in his excellent treatise on 

 this subject, estimates the loss of heat from the extensive sur- 

 face of glass required in a hot-house as unavoidable, and very 

 great ; and, to compensate for this loss, I would propose that 

 the fire, instead of being suffered to die out in the evening, 

 (as in a dwelling-house,) should be replenished with fuel, be- 

 fore the out-house is left for the night; in which case, a self- 

 acting ventilator to regulate the temperature, as noticed in 

 the Gardener's Magazine, (vol. i. p. 419.) might be useful. 

 But, perhaps, a still better plan would be, when the fuel in the 

 stove is in a red heat, and combustion has nearly ceased, to close 

 the chimney by a damper, for the purpose of cutting off its com- 

 munication with the external atmosphere, and thus to bottle up 

 the heat, (if I may be allowed the expression,) on the plan 

 recommended by Dr. Anderson. 



Mr. Boyce uses no damper in the smoke-flue of his appar- 

 atus, but I am persuaded a damper might be applied with ad- 

 vantage ; and the amount of its effect, it is my intention, at no 

 distant period, to ascertain by experiment. 



