VENTILATION 243 



Ventilation. The subject of ventilation is a broad one, since 

 sb many factors enter into the problem of securing it. The rate 

 at which air should be renewed is influenced by the number of 

 people in a room, also by the occupations carried on therein, as 

 can be easily understood. Even in small rooms the quantity of 

 air may be sufficient, if a constant current of renewal be secured. 

 The well-known morning "closeness" of the air of a sleeping room 

 is due to the fact that in the quiet of the night the ordinary air- 

 currents are not present. It is the lack of oxygen rather than 

 the excess of carbon dioxide which is felt and which is in reality 

 the more serious. 



Important Note. The importance of fresh air in sufficient quantity cannot 

 be over-estimated. One thousand cubic feet of space for each adult (equal 

 to a room 10 feet in height, length and breadth), renewed about three times 

 hourly, is not too much. 



