Paper, 'On an explanation of Hall's phenomenon' by S [Shelford] Bidwell

Description

Bidwell writes: 'Mr E H Hall’s first paper relating to what is now generally known is the “Hall effect” appeared in the “Phil. Mag.” for March, 1880. It was entitled “On a New Action of the Magnet on Electric Currents” and in it was described the following experiment:—A strip of gold-leaf was cemented to a plate of glass and placed between he poles of an electromagnet, the plane of the glass being perpendicular to the magnetic lines of force. A current derived from a Bunsen cell was passed longitudinally through the gold, and before the electromagnet was excited two equipotential points were found, by trial, near opposite edges of the gold-leaf and about midway between the ends; when these points were connected with a galvanometer there was, of course, no deflection. A current from a powerful battery being passed through the coils of the magnet, it was found that a galvanometer deflection occurred indicating a difference of potential between the two points, the direction of the current across the gold-leaf being opposite to that in which the gold-leaf itself would have moved across the lines of force had it been free to do so. On reversing the polarity of the magnet, the direction of the transverse (electromotive force was reversed; and when the magnet was demagnetised the two points reverted to their original equipotential condition. The phenomenon is attributed by the author to the direct action of the magnet upon the current in the gold leaf. In a second paper, published in the “Phil. Mag.” for November, 1880, experiments are described in which other metals were used in addition to gold. With silver, nickel, tin, and platinum the nature of the effect was the same as with gold though differing in degree; but in the case of iron the direction of the transverse current was found to be reversed, a result which Mr Hall was naturally inclined to connect with the magnetic properties of iron, and which he says had been predicted by Professor Rowland. But he was greatly puzzled to account for the fact that the two strongly magnetic metals, iron and nickel, gave opposite effects.'

Annotations in pencil and ink. Includes five pages of diagrams relating to Bidwell's experiments.

Subject: Electricity

Received 14 February 1884. Read 21 February 1884.

A version of this paper was published in volume 36 of the Proceedings of the Royal Society as 'On an explanation of Hall's phenomenon'.

Reference number

PP/4/30

Earliest possible date

1884

Physical description

Ink and graphite pencil on paper

Page extent

24 pages

Format

Manuscript
Diagram