DRAUGHT. 315 



supply the void caused in the room (by the 

 escape of warm air up the chimney, &c.) 



Q. Why is there always a DRAUGHT through 

 the WINDOW crevices ? 



A. The external air (being colder 

 than the air of the room we occupy) 

 rushes through the window crevices to 

 supply the deficiency, caused by the escape 

 of air up the chimney, &c. 



Q. Why is there more DRAUGHT if you open 

 the LOWER SASH of a window, than if you open the 

 UPPER sash ? 



A. If the lower sash be open, the 

 cold external air will rush more freely 

 into the room ; but if the upper sash be 

 open the heated air of the room will rush 

 out ; and (of course) there will be less 

 draught. 



Q. By which means is the ROOM better 

 VENTILATED, by opening the lower or the upper sash ? 



A. A room is better ventilated by 

 opening the upper sash ; because the hot 

 vitiated air (which always ascends towards 

 the ceiling) can better escape. 



Q. By which means is a HOT ROOM more 

 quickly COOLED By opening the upper or the lower 

 sash ? E a 2 



