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and the needle on another piece, and let them float on water, at a little distance from each other, and you observe that the magnet moves to. wards the iron, as much as the iron moves towards the magnet.

Charles. If two magnets were put in this situation, what would be produced?

Tutor. If poles of the same name, that is, the two north, or the two south, be brought near together, they will repel one another; but if a north and south pole be presented, the same kind of attraction will be visible, as there was between the magnet and needle.

James. : Will there be any attraction or repulsion if other bodies, as paper, or thin slips of wood, be

placed between the magnets, or between the magnet and iron?

Tutor. Neither the magnetic attraction nor repulsion is in the least diminished, or in any way affected by the interposition of any kind of bodies, except iron. Bring the magnets together within the attracting or repelling distance, and hold a slip of wood between them : you see they both come to the wood.

Charles. You said that iron was more easily rendered magnetic than steel, does it retain the properties as long too?

Tutor. If a piece of soft iron, and a piece of hard steel, be brought within the influence of a magnet, the iron will be most forcibly attracted, but it will almost instantly

lose its acquired magnetism, whereas the hard steel will preserve it a long time.

James. Is magnetic attraction and repulsion at all like what we have sometimes seen in eleetricity?

Tutor. In some instances there is a great similarity : Ex. I tie two pieces of soft wire (Vol. VI. Plate 11. Fig. 28*.), each to a separate thread which join at top, and let them hang freely from a hook x. If I bring the marked or north end of a magnetic bar just under them, you will see the wires repel one another, as they are shown in the figure hanging from %.

Charles. Is that occasioned by the repelling power which both wires have acquired in consequence of be

The reader must turn to Vol. VI. Plate II, for the figures referred to in Magnetism.

*

ing both rendered magnetic with the same pole?

Tutor. It is : and the same thing would have occurred if the south pole had been presented instead of the north.

James. Will they remain long in that position?

Tutor. If the wires are of very soft iron they will quickly lose their magnetic power; but if steel wires be used, as common sewing needles, they will continue to repel each other, after the removal of the magnet.

Ex. II. I lay a sheet of paper flat upon a table, and strew some iron filings upon it. I now lay this small magnet (Vol. VI. Fig. 29.) among them, and give the table a few gentle knocks, so as to shake the filings, and you observe in what manner they have ranged themselves about the magnet. :

Charles. At the two ends or poles, the particles of iron form theinselves into lines, a little sideways; they bend, and then form complete arches, reaching from some point in the northern half of the magnet to some other point in the southern half.--- Pray how do you account for this? 1

۱: Tutor. Each of the particles of iron, by being brought within the sphere of the magnetic influence, becomes itself magnetic, and possessed of two poles, and consequently disposes itself in the same manner as any other magnet would do, and

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