Of the Sahibrity of Warm Rooms. 577 



These are strong facts, and the evidence they afford 

 in the case under consideration is pointed, and appears 

 to me to be incontrovertible. There are many other 

 similar facts that might be adduced in support of the 

 position we are endeavouring to establish. 



It has often been objected to warm rooms, that the 

 air in them is always confined, and consequently un- 

 wholesome ; but no argument more perfectly ground- 

 less and nugatory was ever adduced in support of a 

 bad cause. 



When in cold weather a room is kept warm, the air 

 in it, so far from being confined, is continually chang- 

 ing. Being specifically lighter, in consequence of its 

 being warm, than the air without, it is impossible to 

 open and shut a door without vast quantities of it being 

 forced out of the room by the colder air from without, 

 which rushes in ; and if at any time it be required to 

 ventilate the room in so complete a manner that not a 

 particle of the air in it shall remain in it, this may be 

 done in less time than one minute, merely by letting 

 down the top of one of the windows, and at the same 

 time opening a door which will admit the external colder 

 and heavier air. And it must not be imagined that 

 the room will be much cooled in consequence of this 

 complete ventilation. So far from it, a person return- 

 ing into it, three or four minutes after it had been ven- 

 tilated and the air in it totally changed, would not find 

 its temperature sensibly altered. 



The walls of the room would still be nearly as warm 

 as before, and the radiant heat from those walls, pass- 

 ing through the transparent air of the room without 

 any sensible diminution of their calorific powers, would 

 produce the same sensation .of warmth as they did 



VOL. iv. 37 



