Page:On the various forces of nature and their relations to each other.djvu/147

Rh taken a quarter of an hour or more to reach the first ball?

Here is another experiment, for the purpose of shewing the conductibility of this power through some bodies, and not through others. Why do I have this arrangement made of brass? [pointing to the brass work of the electrical machine, fig. 41]. Because it conducts electricity? And why do I have these columns made of glass? Because they obstruct the passage of electricity. And why do I put that paper tassel (fig. 43) at the top of the pole, upon a glass rod, and connect it with this machine by means of a wire? You see at once that as soon as the handle of the machine is turned, the electricity which is evolved travels along this wire and up the wooden rod, and goes to the tassel at the top, and you see the power of repulsion with which it has endowed these strips of paper, each spreading outwards to the ceiling and sides of the room. The outside of that wire is covered with gutta-percha. It would not serve to keep the force from you when touching it with your hands, because it would burst through; but it answers our purpose for the present. And so