CHEMICAL HISTORY OF A CANDLE 107 



ranged. Suppose I take this candle, and hold a piece of 

 paper close upon the flame, where is the heat of that flame? 

 Do you not see that it is not in the inside? It is in a ring, 

 exactly in the place where I told you the chemical action 

 was; and even in my irregular mode of making the experi- 

 ment, if there is not too much disturbance, there will always 

 be a ring. This is a good experiment for you to make at 

 home. Take a strip of paper, have the air in the room quiet, 

 and put the piece of paper right across the middle of the 

 flame (I must not talk while I make the experiment) and 

 you will find that it is burnt in two places, and that it is not 

 burnt, or very little so, in the middle; and when you have 

 tried the experiment once or twice, so as to make it nicely, 

 you will be very interested to see where the heat is, and to 

 find that it is where the air and the fuel come together. 



This is most important for us as we proceed with our 

 subject. Air is absolutely necessary for combustion; and, 

 what is more, I must have you understand that fresh air is 

 necessary, or else we should be imperfect in our reasoning 

 and our experiments. Here is a jar of air; I place it over 

 a candle, and it burns very nicely in it at first, showing that 

 what I have said about it is true; but there will soon 

 be a change. See how the flame is drawing upward, pres- 

 ently fading, and at last going out. And going out, why? 

 Not because it wants air merely, for the jar is as full now 

 as it was before; but it wants pure, fresh air. The jar is 

 full of air, partly changed, partly not changed; but it does 

 not contain sufficient of the fresh air which is necessary for 

 the combustion of a candle. These are all points which we, 

 as young chemists, have to gather up ; and if we look a little 

 more closely into this kind of action, we shall find certain 

 steps of reasoning extremely interesting. For instance, here 

 is the oil-lamp I showed you an excellent lamp for our 

 experiments the old Argand lamp. I now make it like a 

 candle [obstructing the passage of air into the centre of the 

 flame] ; there is the cotton ; there is the oil rising up in 

 it, and there is the conical flame. It burns poorly because 

 there is a partial restraint of air. I have allowed no air to 

 get to it save around the outside of the flame, and it does 

 not burn well. I can not admit more air from the outside, 



