VI 



THE COMPOSITION OF THE AIR 



49 



Experiment 30 



Fill a little brazier with lumps of charcoal and 

 set the charcoal on fire. When it is burning brightly 

 arrange over it a tin funnel with a glass tube passing 

 away at the top to a bell-jar through a cork, and 

 arrange another tube from the top of the bell-jar and 

 connected through a cork with a tin can full of water, 

 with a tap at the bottom. Place a lighted candle on 



FIG. 13. 



a ground glass plate and fit the bell-jar, rubbed 

 round the edge with vaseline, over it, and draw a 

 stream of air through the whole apparatus by turn- 

 ing on the tap of the tin can. 



As long as ordinary air is passing through, the 

 candle burns ; but as soon as the tin funnel is placed 

 over the brazier, so as to collect the air from the 

 burning charcoal, the candle goes out. 



In order that we may be sure of the nature of 

 E 



