CHEMICAL AFFINITY SI 



bustible. There is a jar full of it; and if I carry it along 

 in this manner and put a light to it, I think you will see it 

 take fire not with a bright light; you will, at all events, 



FIG. 27 



hear it if you do not see it. Now that is a body entirely 

 different from oxygen; it is extremely light; for, although 

 yesterday you saw twice as much of this hydrogen produced 

 on the one side as on the other by the voltaic battery, it was 

 only one-eighth the weight of the oxygen. I carry this jar 

 upside down. Why ? Because I know that it is a very light 

 body, and that it will continue in this jar upside down quite 

 as effectually as the water will in that jar which is not upside 

 down; and just as I can pour water from one vessel into 

 another in the right position to receive it, so can I pour this 

 gas from one jar into another when they are upside down. 

 See what I am about to do. There is no hydrogen in this 

 jar at present, but I will gently turn this jar of hydrogen 

 up under this other jar (FiG. 28), and then we will examine 

 the two. We shall see, on applying 

 a light, that the hydrogen has left the 

 jar in which it was at first, and has 

 poured upward into the other, and 

 there we shall find it. 



You now understand that we can 

 have particles of very different kinds, 

 and that they can have different bulks 

 and weights; and there are two or 

 three very interesting experiments which serve to illustrate 

 this. For instance, if I blow soap bubbles with the breath 

 from my mouth, you will see them fall, because I fill them 



