174 Mr Hart on Heating Apartments. 



inches, and the combined openings into the rooms nearly the same 

 size ; the air, therefore, is seldom above 100°, imless some of the 

 registers are shut. A damper is likewise placed where it enters 

 the vent, which is generally shut so soon as the fire goes out, to 

 retain the heat. 



If the damper is shut, the apparatus, after the fire is with- 

 drawn, will still be found giving out an agreeable warmth for 

 two days after; in this property it resembles the brick-stoves of 

 Russia or Holland. The cockle I was inquiring after would 

 have occupied a space of six feet cube for the brick-work alone, 

 and was to have cost L. 40 ; whereas this apparatus Avas put up 

 for the following sum : — 



Six cast-iron Mains, - - L. 7 10 



Two Dampers, Door, and Cover for tiie 



Fire-place, - - - 10 



Brick-work, - - - 2 



L.IO 10 



Besides, serious accidents have several times occurred with 

 the common cockle, from the brick-work giving way between 

 the furnace and the air-flue, through which the flame or sparks 

 found a passage into the buildings. It must be evident, how- 

 ever, on inspection, that no danger of this kind can arise from 

 this arrangement, as the communication wilh the air-tunnel, or 

 lower end of the pipes, passes outside of the wall of the furnace 

 altogether, so that no fire or sparks can ever get into the tubes ; 

 and, as their other ends project a foot beyond the opposite 

 wall before they enter the heated air-flue, no sparks or dust can 

 enter by that end. 



In constructing a stove of this kind, care must be taken that 

 the brick-woi'k rest on one end of the tubes only, as their alternate 

 expansions and contractions would soon rend the building ; the 

 tubes, therefore, must be free at one of their extremities, and 

 the joints simply pointed round. I am, &c. 



John Hart. 



Mitcheix-Street, Gl.a.sgow, 

 Nov. 30. 1829. 



