PART III. ARCHITECTURE. 139 



fire-place, or fuel chamber, built with stone or brick on three 

 sides, and open in front. C the ash pit, and D the floor of the 

 house. Then suppose fig. 6. a section of this gable and chim- 

 ney. E is the grate that contains the fuel, placed on a level 

 with the surface of the floor, which is represented by F. G the 

 solid wall, or gable, which projects completely over the fire. 

 H the vent or funnel by which the smoke escapes. 



The advantage of this plan is, that more heat is thrown out 

 into the apartment by a given quantity of fuel. This is 

 effected, 1st, By the lowness of the fire-place ; 2dly, By the 

 projection over it, which makes the smoke ascend very slowly, 

 and thus gives it time to cool, or give out its heat into the 

 room. 3dly, By having the vent at H of proper dimensions; 

 that is, such as will neither permit more nor less than the re- 

 quisite quantity of smoke and air to escape. I have generally 

 found in like cases, that its superficial contents should be equal 

 to that of the upper surface of the fuel chamber. 



These circumstances occurred to me in the course of making 

 experiments for heating rooms (a branch of domestic economy, 

 which, notwithstanding the meritorious labours of Franklin 

 and Rum ford, still affords an ample field for discovery and im- 

 provement) : and should they tend to benefit the labouring 

 ' poor, which I think they may in a remarkable degree, if pro- 



