WARMING AND VENTILATING OCCUPIED BUILDINGS. 



Above the room to be warmed, the warm-air shaft is discontinued and 

 the flue carried up in the usual way. If, however, it be desired to use 

 the shaft for warming rooms above, it may be prolonged ; a register being 

 fitted to it at each floor to regulate its action. 



The hearths of these fire-places should be arranged as in common fire- 

 places. They should be made of cast iron, and the fire place lined with 

 fire-brick if coal or coke is to be used. A movable blower should be 

 arranged to be used for kindling the fire. 



15. Observation relative to large rooms. — It is proper to repeat here that 

 the dimensions given for these ventilating fire-places cannot be much 

 increased, even for the largest rooms. But while two fire-places of the 

 usual form, placed in the same room, often interfere with each other, 

 the same difficulty is not experienced with ventilating fire-places, which 

 supply themselves with the air necessary for draught. 



Still, in such cases, it is better, in addition to the fire-places, to employ 

 heaters, arranged according to the principles given further on, to be 

 chiefly used in warming vestibules, stairways, corridors, anterooms, 

 &c., only introducing into the living-rooms warm air, which has the 

 moderate temperature of 94° to 100° in the upper portions. 



STOVES. 



16. Domestic use. — Stoves, usually placed within the room, form the 

 most economical method of heating. Those which are made of porce- 

 lain, sheet-iron, or cast iron, without hot-air passages, and deriving 

 their supply of air from the rooms in which they are placed, give out 

 into the rooms they warm 85 to 90 per cent, of the heat produced by the 

 fuel. (Fig. 11.) 



But the amount of air which passes through 

 the stove and escapes up the chimney is only 

 about 80 cubic feet to each pound of wood 

 burned, from 96 to 112 cubic feet to each 

 pound of coal, and from 160 to 192 cubic feet 

 to each pound of coke, even with a brisk fire. 

 Stoves of this kind only produce a very slow 

 change of air, equal, at most, to one-tenth the 

 capacity of the place warmed, the air of which 

 consequently would only be completely changed 

 by them once in ten hours. 



Warmiug by means of stoves is, then, evi. 

 dently iuj urious to health. They have, besides, 

 the defect of causing considerable diflerences 

 between the temperatures which prevail at 

 different heights. These differences may be 

 as much as 18° or 20° in rooms 13 to 16 feet 

 high. 



17. Injurious effects produced by cast-iron 

 stoves. — Cast-iron stoves are much more inju- 

 rious than porcelain ones on account of the great and irregular heating of 



