The same influence which affects the magnetic needle already described,
will also communicate magnetism to soft iron. If a bar of that metal
bent, be surrounded with a common bonnet wire, or a copper wire
prevented from touching the iron by a winding of cotton or thread, and
then if a current of voltaic electricity be sent through the wire, the
bar becomes a powerful magnet, and will continue so as long as the
connection with the battery is preserved. On breaking the contact, the
magnetism disappears. This experiment may be easily made by the young
reader with a horse-shoe magnet, surrounded by several coils of wire.