CHEMICAL HISTORY OF A CANDLE 171 



second candle. If I took the air proceeding from another 

 candle, and sent it down by a complicated arrangement into 

 this tube, I should put this burning candle out. But what 

 will you say when I tell you that my breath will put out 

 that candle? I do not mean by blowing at all, but simply 

 that the nature of my breath is such that a candle can not 

 burn in it. I will now hold my mouth over the aperture, 

 and without blowing the flame in any way, let no air enter 

 the tube but what comes from my mouth. You see the 

 result. I did not blow the candle out. 

 I merely let the air which I expired 

 pass into the aperture, and the result 

 was that the light went out for want of 

 oxygen, and for no other reason. Some- 

 thing or other namely, my lungs had 

 taken away the oxygen from the air and 

 there was no more to supply the com- 

 bustion of the candle. It is, I think, very 

 pretty to see the time it takes before 

 the bad air which I throw into this part 

 of the apparatus has reached the can- 

 dle. The candle at first goes on burn- 

 ing, but so soon as the air has had time 

 to reach it it goes out. And now I 

 will show you another experiment, be- FlG g 



cause this is an important part of our 

 philosophy. Here is a jar which contains fresh air, as 

 you can see by the circumstance of a candle or gas- 

 light burning it. I make it close for a little time, and 

 by means of a pipe I get my mouth over it so that I 

 can inhale the air. By putting it over water, in the 

 way that you see, I am able to draw up this air (supposing 

 the cork to be quite tight), take it into my lungs, and throw 

 it back into the jar: we can then examine it, and see the 

 result. You observe, I first take up the air, and then throw 

 it back, as is evident from the ascent and descent of the 

 water; and now, by putting a taper into the air, you will 

 see the state in which it is by the light being extinguished. 

 Even one inspiration, you see, has completely spoiled this air, 

 so that it is no use my trying to breathe it a second time. 



