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CORRELATION OF THE PHYSICAL FORCES.
Here again is a fine illustration of this strong power of magnetism. It is a magnet of the
Fig. 53.
same sort as the one you have just seen. I am about to make the current of electricity pass through the wires which are round this iron for the purpose of showing you what powerful effects we get. Here are the poles of the magnet; and let us place on one of them this long bar of iron. You see as soon as contact is made how it rises in position (fig. 54); and if I take such a piece as this cylinder, and place it on, woe be to me if I get my finger between; I can roll it over, but if I try to pull it off, I might
