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James. Will there be any attraction or repulsion if other bodies, as paper, or thin slips of wood, be placed between the maggets, or between the magnet and iron?

Tutor. Neither the magnetic attraction nor repulsion is in the least diminished, or in any away 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 J

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 along time.

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

them, you

Tutor. In some instances there is a great similarity : Ex. I tie two pieces of soft wire Plate vill. Fig. 28.) each to a separate thread which juin 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

will see the wires repel one ano. ther, as they are shown in the figure hanging from z.

Charles. Is that occasioned by the repelling power which both wires have acquired in consequence of being 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 роsition ? 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 ito

I now lay this small magnet 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 themselves 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?

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 also attracts with its extremities the contrary poles of other particles.

Ex. III. If I shake some iron filings through a gauze sieve, upon a paper that

covers a bar magnet, the filings will become que magnets, and will be arranged in beautiful curves.

R

VOL. III.

James. Does the polarity of the magnet reside only in two ends of its surface?

Tutor. No: one half of the magnet is possessed of one kind of polarity, and the other of the other kind; but the ends, or poles, are those points in which that power is the strongest.

DEF. A line drawn from one pole to the other is called the axis of the magnets

CONVERSATION XXV.

The Method of making Magnets-m..Of the Mariner's

Compass.

TUTOR. I have already told you

that artificial magnets, which are made of steel, are now generally used in preference to the real magnet, because they can be procured with greater ease, may be varied in their form more easily, and will communicate the magnetic virtue more powerfully.

Charles. How are they made?

Tutor. The best method of making artificial magnets is to apply one or more powerful magnets to pieces of hard steel,

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