| The Revolving Magnet surely had the longest survival of
any of the Davis/Page apparatus. The first description of it is in
a note written for Benjamin Silliman's American Journal of Science
in August 1837, and it can be found as Page's Motor Apparatus in
the 1916 catalogue of the L. E. Knott Apparatus Company of Boston.
The apparatus was originally designed by Charles
Grafton Page as a motor, but the cut from the 1842 edition of the Manual
of Magnetism shows it being used as a generator. Its cost was $5.00
in 1842; by 1916 it cost $8.50. In both eras it could be obtained with
a permanent magnet or an electromagnet. |
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