of them weighing three pounds averdupois would lift another of the same
weight. Philos. Trans.

After this Dr. Knight made very successful experiments on this subject,
which, though he kept his method secret, seems to have excited others to
turn their attention to magnetism. At this time the Rev. Mr. Michell
invented an equally efficacious and more expeditious way of making
strong artificial magnets, which he published in the end of the year
1750, in which he explained his method of what he called "the double
touch", and which, since Mr. Knight's method has been known, appears to
be somewhat different from it.

This method of rendering bars of hardened steel magnetical consists in
holding vertically two or more magnetic bars nearly parallel to each
other with their opposite poles very near each other (but nevertheless
separated to a small distance), these are to be slided over a line of
bars laid horizontally a few times backward and forward. See Michell on
Magnetism, also a detailed account in Chamber's Dictionary.

What Mr. Michell proposed by this method was to include a very small
portion of the horizontal bars, intended to be made magnetical, between
the joint forces of two or more bars already magnetical, and by sliding
them from end to end every part of the line of bars became successively
included, and thus bars possessed of a very small degree of magnetism to
begin with, would in a few times sliding backwards and forwards make the
other ones much more magnetical than themselves, which are then to be
taken up and used to touch the former, which are in succession to be
laid down horizontally in a line.

There is still a great field remains for future discoveries in magnetism