DESCRIPTION OF A STOYtt. 25 



Hence we deduce the following obvious confequences : Corollaries dc- 



1. The fire-place mull be kept feparate from all bodies that 

 conduct heat rapidly. 



2. As heat can be produced only by combuftion, and com- 

 buflion can be maintained only by a current of air, this cur- 

 rent mould be attracted into pipes, where it preferves the re- 

 quifite velocity, without going away from the place to be 

 heated ; fo that the heat it depofits in it gradually accumulates 

 in the whole of the ifolated ilove, to be afterward given out 

 (lowly, according to the laws of its equilibrium 



3. When the wood is confumed to fuch a point as to afford 

 no more fmoke, it is of advantage to flop the outlets of thefe 

 pipes, to keep in the heat, which would be carried into the 

 chimney by the continued current of frelh air, which would 

 necellarily be of a lower temperature. 



4. Wc mall obtain a higher temperature, and preferve it Apertures f« 

 longer, under fimilar circumftances, if we conftrucl within the heated aiu 

 ilove, or under the hearth and round the fire-place, pipes in 



which the air derived from without is warmed before it enters 

 into the apartment to fupport the fire, or to replace what has 

 been confumed. 



Thefe pipes are what have been called heat openings, 

 (bouches de chaleur,) becaufe inllead of confidering their prin- 

 cipal objecl, it is commonly fuppofed, that they are made to 

 give a more rapid palTage to the heat produced. This is not 

 totally without foundation, fince the temperature of the air 

 iffuing from them is iacreafed by the heat it abforbs from the 

 dove; and on tkis account fome might be difpofed to neglect 

 them, as contrary to the moll elTential objecl, that of retaining 

 the heat in it; but it is to be obferved, that we can fhut thefe 

 outlets when we pleafe ; and that we may even cut off all 

 communication with the external air by means of a fimple 

 ilider; fo that every advantage may be derived from them 

 without any inconvenience. It mull be added, that they are Neceffbrylnvery 

 necelTary in very clofe apartments, unlefs we would expofe clofea ' a ' tmeaU * 

 ourfelves to currents of cold air. Thefe reafons have induced 

 me to employ the heat openings in the Svvedifli ilove, to which 

 they had not been applied. 



The Swedifh ftoves are conflrucled flrictly according to the Swedl/h floves 

 truell principles, and the pipes in which'the fmoke circulates *, on( * r "^ ° n 



,. . r \ * r the be it princi- 



ple dilpoled in the pelt manner for effecting its complete com- pics. 



buOion. 



