him, within the body of the bird, a large needle,
which lay across it from one end to the other. In the bread with which
the swan was fed, he also showed him concealed a small bar of iron.
Tommy could not comprehend all this, although he saw it before his eyes;
but Mr Barlow, who was present, taking up the bar of iron, and putting
down several needles upon the table, Tommy was infinitely surprised to
see the needles all jump up, one after another, at the approach of the
bar, and shoot towards it, as if they had been possessed of life and
sense. They then hung all about the bar so firmly, that, though it was
lifted into the air, they all remained suspended, nor ever quitted their
hold. Mr Barlow then placed a key upon the table, and putting the iron
near it, the key attached itself as firmly to the bar as the needles had
done before. All this appeared so surprising to Tommy, that he begged an
explanation of it from Mr Barlow. That gentleman told him, "that there
was a stone often found in iron mines, that was called the _loadstone_.
This stone is naturally possessed of the surprising power of drawing to
itself all pieces of iron that are not too large, nor placed at too
great a distance. But what is equally extraordinary is, that iron
itself, after having been rubbed upon the loadstone, acquires the same
virtue as the stone itself, of attracting other iron. For this purpose
they take small bars of iron, and rub them carefully upon the loadstone,
and when they have acquired this very extraordinary power, they call
them _magnets_. When Harry had seen the exhibition of the swan, upon
revolving it over in his mind, he began to suspect that it was
performed entirely by the power of magnetism. Upon his talking to me
about the affair, I confirmed him in his opinion, and furnished him with
a small magnet to put into the bread, and a large needle to conceal in
the body of the bird. So this is the explanation of the feat which so
much puzzled you a few days past."

Mr Barlow had scarcely done speaking, when Tommy observed another
curious property of the swan, which he had not found out before. This
bird, when left to itself, constantly rested in one particular
direction, and that direction was full north and south.

Tommy inquired the reason of this, and Mr Barlow gave him this
additional explanation: "The persons who first discovered the wonderful
powers of the loadstone, in communicating its virtues to iron, diverted
themselves