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A LECTURE 0N MAGNETISM. 365

right in yOur left hand, and cause the testaneedle to ap-
proach the lower end of your strip; one end is attracted,
the other is repelled. Raise your needle along the strip;
its oscillations, which at first were quick, become slower;
opposite the middle of the strip they cease entirely; neither
end of the needle is attracted; above the middle the test-
needle turns suddenly round, its other end being now at-‘-
tracted. Go through the experiment thoroughly; you thus
learn that the entire lower half of the strip attracts one end
of the needle, while the entire upper half attracts the oppo-
site end. Supposing the north end of your little needle to
be that attracted below, you infer that the entire lower half
of your magnetized strip exhibits south magnetism, while
the entire upper half exhibits north magnetism. So far,
then, you have determined the distribution of magnetism in
your strip of steel.

You look at this fact, you think of it; in its suggestive-m-
ness the value of the experiment chiefly consists. The
thought arises, “What will occur if I break my strip of
steel across in the middle ? Shall I obtain two magnets,
each possessing a single pole?” Try the experiment;
break yOur strip of steel, and test each half as you tested
the whole. The mere presentation of its two ends in suc-
cession to your test-needle suffices to show you that you
have not a magnet with a single pole, that each half pos-
sesses two poles with a neutral point between them. And
if you again break the half into two other halves, you will
find that each quarter of the original strip exhibits precisely
the same magnetic distribution as the strip itself. You
may continue the breaking process; no matter how small
your fragment may be, it still possesses two opposite poles
and a neutral point between them. Well, your hand ceases
to break where breaking becomes a mechanical impossi-
bility; but does the mind stop there? N 0: you follow
the breaking process in idea when you can no longer realize

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