136 



CHEMISTRY. 



be no burning without oxygen. But as the gas is contin- 

 ually forming, and pressing upward and outward, some of 

 it passes all the time into 2, where it mingles with the oxy- 

 gen and takes fire. While the form of each of the parts of 

 the flame remains the same, the matter in them is continual- 

 ly changing. 



173. Experiments. What we have said of the flame of a 



candle can be verified by many 



very interesting experiments. If 

 we place one end of a small tube 

 in the dark part of the flame, Fig. 

 53, some of the unburned gas will 

 pass through the tube, and may be 

 lighted at the other end. This ex- 

 periment may be tried in another 

 Fig. 53. form, as represented in Fig. 54. 



Here the gas passes into a flask. After considerable has 

 passed in we can take out 

 the tube, and with a match 

 set fire to the gas which we 

 have thus collected. We 

 do the same thing essential- 

 ly if we throw a piece of 

 candle into the flask, and 

 then vaporize it by a strong 

 heat. The same gas that 

 we have in the dark part 

 of the flame of a candle is 

 collected there, and we can 

 set fire to it. If you put a 

 small slip of wood directly 

 across the flame of a candle, Fi - 54< 



just above the wick, so that the middle of it will be in the 

 dark part, and hold it there a few seconds, on taking it out 



