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WARMING AND VENTILATING OCCUPIED BUILDINGS. 



OPEN FIKE-PLACES. 



3. At the head of comfortable and healthful forms of heating-appa- 

 ratus used within buildings are placed open fire-places, of which two 

 different kinds may be distinguished : 



1. Ordinary fire-places. 



2. Ventilating fire-places. 



The remarks which will be made in regard to the first, and the 

 proportions suitable for them, will also apply to the second, which, in- 

 deed only differ by having some special arrangements. 



COMMON PIRE-PLACES. 



Two distinct types may be considered. The first, 

 which is the one most frequently met with, consists 

 of a chimney of proper size, connected with the 

 hearth at the bottom by means of a more or less 

 narrow opening, the lower part of which forms the 

 passage which Eumford called the throat of the 

 chimney, (Fig. 1.) On the upper part of the flue 

 is placed a sort of ajutage, called a chimney-shaft 

 when built of bricks or tiles, and chimney-cap when 

 Tit 



made of terra-cotta, (Fig. 2.) The opening 



for the escape of the smoke is much smaller 

 than the sectional area of the main flue. 

 This type is almost the same as that de- 

 vised by Eumford, and which bears his 

 name; but while he pointed out its advantages 

 over the old forms of chimneys in regard to draught, 

 he did not determine the correct proportions of the 

 several parts. ^ 



In the second type, often met with in the upper stories of houses in 

 Paris, the flue, which is usually cylindrical, has the same sectional 

 area throughout. It has been recommended by M. Peclet, in his. treatise 

 on heat, as proper for every case ; but its use should be restricted to 

 very small chimneys, and, in general, to cases where stoves are used for 

 heating. 



4. General advantages and disadvantages of ordinary fire-places. — Ordi- 

 nary fire-places, which cause the removal of a considerable amount of 

 air, and, therefore, the change of that in the apartments, present the 

 incontestable advantage of forming a healthful mode of heating. But 

 the air which is removed must necessarily be replaced by the external 

 air, entering usually through the loose joints of the doors and windows, 

 thus causing currents of cold air, which become more unpleasant the 

 greater the size of the chimney or the stronger the draught produced by 

 the fire. Consequently, as Eumford says, " the draughts chill one part 

 of the body, while the rest is roasted by the fire in the fire-place, and 

 this cannot but be injurious to health." All have noticed these effects 



