Professor Hoskinff on Ventilation. 303 



•& 



within our dwellings when daylight fails, we introduce another 

 sharer in the pent-up air of our rooms, being fire indeed in another 

 form, but generally under such circumstances, that it not only ab- 

 stracts from the quantity, but injures the quality of what may re- 

 main. But fire, whether in the animal system, in the grate, or in 

 the lamp, cannot long endure the imagined limitation of air. There 

 must be access of air — of vital air — by some channel or other, or 

 the fire will go out. 



An open tire in the grate must however have a vent for some 

 of its results, or it will bo so disagreeable a companion that its 

 presence could not be endured, even as long as the most limited 

 quantity of air would last ; and the fire will compel the descent of air 

 by the vent commonly* supplied under the name of a flue — a chimney 

 flue — to render its presence tolerable in a closed room, if a supply 

 be not otherwise obtainable. But as the outer air at the higher level 

 of the top of a chimney, because of the rarity of the air in and above 

 the flue, responds to the demand of the fire less easily than the 

 lower air, or that at and about the level of the fire ; and the lower 

 air, or air at the lower levels, forces its way in, therefore, by any 

 opening it can find or make — through the joints of the flooring- 

 boards, and under the skirtings — the supply passing first up or 

 down the hollow lathed and plastered partitions, sometimes even 

 up from the drains ; and through the joints under and about the 

 doors and windows. If these channels do not exist, as they may not 

 when the joiners' work and the plastering are good, or when the open 

 joints referred to are stopped up by any means, the fire smokes, and 

 every known means of curing the chimney failing, means are sought 

 of obtaining heat without the offending fire. Ventilation is not 

 thought of yet. 



The open fire may be made to give place to the close stove or to 

 hot-air — pipes, to hot- water pipes, or to steam-pipes — which make hot 

 the air about them in a close room without causing draughts. But 

 the warmth obtained in pipes is costly under any circumstances. Air 

 does not take up heat freely, unless it be driven and made to pass 

 freely over the heated surface ; and there being little or no con- 

 sumption of air, and consequently little or no draught, in connexion 

 with heated bodies, such as close stoves and hot pipes, the heat from 

 them is not freely diffused, and is not wholesome. There is with all 

 the expense no ventilation. 



Stoves and hot pipes are, moreover, exceedingly dangerous inmates 

 in respect of fire. Such things are the most frequent causes, directly 

 or indirectly, of fires in buildings. Placed upon, or laid among or 

 about the timbers and other wood-work of hollow floors, and hollow 

 partitions, and in houses with wooden stairs, more conflagrations 

 are occasioned by hot pipes and stoves, than by any thing else, and 

 perhaps more than by all other things together. 



Open stoves with in-draught of air warmed by being drawn quickly 



