though the result is the same in so far as it gives us certain gaseous particles. Here then is the hydrogen. I showed you yesterday certain qualities of this gas, now let me exhibit you some other properties. Unlike oxygen, which is a supporter of combustion, and will not burn, hydrogen itself is combustible. 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 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
