Lecture

1 II |       shining either light or dark, although I have nothing
2 II |   make it so that it is quite dark, and we will, in the first
3 II |    You see the screen remains dark. The glass, then, internally,
4 II |      the screen still remains dark. Now Dr. Tyndall will press
5 II |      some parts and leaves it dark in others, and all because
6 II |      the screen remains quite dark; but I am going to warm
7 II |   parts which are hot, making dark and light lines just as
8 II | internal condition; for these dark and light parts are a proof
9 III|  cylinder of oxygen, when the dark red vapor of hyponitrous