CHEMICAL HISTORY OP A CANDLE 131 



Hydrogen gives rise to no substance that can become solid, 

 either during combustion or afterward as a product of its 

 combustion ; but when it burns it produces water only ; and if 

 we take a cold glass and put it over the flame, it becomes 

 damp, and you have water produced immediately in apprecia- 

 ble quantity; and nothing is produced by its combustion but 

 the same water which you have seen the flame of the candle 

 produce. It is important to remember that this hydrogen is 

 the only thing in nature which furnishes water as the sole 

 product of combustion. 



And now we must endeavor to find some additional proof 

 of the general character and composition of water, and for 

 this purpose I will keep you a little longer, so that at our 

 next meeting we may be better prepared for the subject. 

 We have the power of arranging the zinc which you 

 have seen acting upon the water by the assistance of an 

 acid, in such a manner as to cause all the power to be 

 evolved in the place where we require it. I have behind 

 me a voltaic pile, and I am just about to show you, at the 

 end of this lecture, its character and power, that you may 

 see what we shall have to deal with when next we meet. 

 I hold here the extremities of the wires which transport 

 the power from behind me, and which I shall cause to act 

 on the water. 



We have previously seen what a power of combustion is 

 possessed by the potassium, or the zinc, or the iron filings; 

 but none of them show such energy as this. [The lecturer 

 here made contact between the two terminal wires of the 

 battery, when a brilliant flash of light was produced.] This 

 light is, in fact, produced by a forty-zinc power of burning; 

 it is a power that I can carry about in my hands through 

 these wires at pleasure, although if I applied it wrongly to 

 myself it would destroy me in an instant, for it is a most 

 intense thing, and the power you see here put forth while 

 you count five [bringing the poles in contact and exhibit- 

 ing the electric light] is equivalent to the power of sev- 

 eral thunder-storms, so great is its force ( u ) And that 

 you may see what intense energy it has, I will take the 



"Professor Faraday has calculated that there is as much electricity re- 

 uired to decompose one grain of water as there is in a very powerful 

 of lightning. 



