CHEMICAL HISTORY OP A CANDLE 



137 



which rises from the water is steam. But can it be steam? 

 Why, certainly not; because there it remains, you sec, 

 unchanged. There it is standing over the water, and it can 

 not therefore be steam, but must be a permanent gas of some 

 sort. What is it? Is it hydrogen? Is it anything else? 

 Well, we will examine it If it is hydrogen it will burn. 



FIG. 73 



[The lecturer then ignited a portion of the gas collected, 

 which burnt with an explosion.] It is certainly something 

 combustible, but not combustible in the way that hydrogen is. 

 Hydrogen would not have given you that noise; but the 

 color of that light, when the thing did burn, was like that 

 of hydrogen; it will, however, burn without contact with 

 the air. That is why I have chosen this other form of appa- 

 ratus, for the purpose of pointing out to you what are the 

 particular circumstances of this experiment. In place of an 

 open vessel, I have taken one that is closed (our battery is 

 so beautifully active that we are even boiling the mercury, 

 and getting all things right not wrong, but vigorously 

 right) ; and I am going to show you that that gas, what- 

 ever it may be, can burn without air, and in that respect 

 differs from a candle, which can not burn without the air. 

 And our manner of doing this is as follows: I have here a 

 glass vessel (G) which is fitted with two platinum wires 

 (IK) through which I can apply electricity; and we can 

 put the vessel on the air-pump and exhaust the air; and 

 when we have taken the air out we can bring it here and 



