Page:On the various forces of nature and their relations to each other.djvu/139

first seem rather strange; and I must therefore shew you an experiment to prove that this is not an accidental matter, but that the whole of the mass is really concerned in this force, just as in falling the whole of the mass is acted upon by the force of gravitation. I have here (fig. 40) a steel bar, and I am going to Fig. 40.make it a magnet, by rubbing it on the large magnet (fig. 39). I have now made the two ends magnetic in opposite ways. I do not at present know one from the other, but we can soon find out. You see when I bring it near our magnetic needle (fig. 38) one end repels and the other attracts; and the middle will neither attract nor repel—it cannot, because it is half-way between the two ends. But now, if I break out that piece (n s), and then examine it—see how strongly one end (n) pulls at this end (S, fig. 38), and how it repels the other end (N). And so it can be shewn that every part of the magnet contains this power of attraction and repulsion, but that the power is only