1*0 FARADAY 



they are. Their bulk is large, and we can easily apply experi- 

 ments to them. I will take this jar (H) first, and will ask 

 you to be prepared to recognize hydrogen. 



Think of all its qualities the light gas which stood well 

 in inverted vessels, burning with a pale flame at the mouth 

 of the jar, and see whether this gas does not satisfy all these 

 conditions. If it be hydrogen it will remain here while I hold 

 this jar inverted. [A light was then applied, when the 

 hydrogen burnt] What is there now in the other jar? You 

 know that the two together made an explosive mixture. 

 But what can this be which we find as the other constituent 

 in water, and which must therefore be that substance which 

 made the hydrogen burn? We know that the water we put 

 into the vessel consisted of the two things together. We find 

 one of these is hydrogen : what must that other be which was 

 in the water before the experiment, and which we now have 

 by itself? I am about to put this lighted splinter of wood 

 into the gas. The gas itself will not burn, but it will make the 

 splinter of wood burn. [The lecturer ignited the end of the 

 wood and introduced it into the jar of gas.] See how it 

 invigorates the combustion of the wood, and how it makes it 

 burn far better than the air would make it burn; and now 

 you see by itself that every other substance which is con- 

 tained in the water, and which, when the water was formed 

 by the burning of the candle, must have been taken from the 

 atmosphere. What shall we call it, A, B, or C? Let us call 

 it O call it " Oxygen ; " it is a very good, distinct-sounding 

 name. This, then, is the oxygen which was present in the 

 water, forming so large a part of it. 



We shall now begin to understand more clearly our 

 experiments and researches, because when we have examined 

 these things once or twice we shall soon see why a candle 

 burns in the air. When we have in this way analyzed the 

 water that is to say, separated or electrolyzed its parts 

 out of it, we get two volumes of hydrogen and one of 

 the body that burns it. And these two are represented 

 to us on the following diagram, with their weights also 

 stated; and we shall find that the oxygen is a very heavy 

 body by comparison with the hydrogen. It is the other 

 element in water. 



