80 



CHEMICAL AFFINITY. 



Now when water is opened out in this way by 

 means of the battery ; which adds nothing to it 

 materially, which takes nothing from it mate- 

 rially (I mean no matter, I am not speaking of 

 force) ; which adds no matter to the water ; it 

 is changed in this way the gas which you saw 

 burning a little while ago, called hydrogen, is 

 evolved in large quantity, and the other gas, 

 oxygen, is evolved in only half the quantity; so 

 that these two areas represent water, and these 

 are always the proportions between the two 

 gases. 



Oxygen 

 Hydrogen 

 Water . 



. 88*9 

 . 11-1 

 . 100-0 



But oxygen is sixteen times the weight of 

 the other eight times as heavy as the par- 

 ticles of hydrogen in the water ; and you there- 

 fore know that water is composed of nine parts 

 by weight one of hydrogen and eight of oxy- 

 gen ; thus : 



