Paper, 'On the effect of magnetisation upon the dimensions of wires and rings of annealed iron' by Shelford Bidwell

Description

Bidwell writes: 'In the year 1885 I submitted to the Royal Society the first of a series of papers upon the changes produced by magnetisation in the dimensions of rods, &c., of iron and other magnetic metals [see PP/8/9]. The chief, and perhaps the most interesting, subject of the paper was the observation that if the magnetising force were sufficiently increased, the extension which a magnetised iron rod at first underwent (as originally noticed by Joule) was followed by contraction, the rod ultimately becoming shorter than when it was unmagnetised. The elongation was generally found to attain a maximum with a magnetising force of from 80 to 120 C. G. S. units, and to vanish with a force of 300 to 400, retraction occurring when still higher forces were applied.'

Annotations in pencil and ink. Includes two pages of graphs and a photograph of the rings of anneated iron used in the experiments.

Subject: Metallurgy / Magnetism

Received 2 March 1894 / 12 March 1894. Read 1 March 1894.

A version of this paper was published in volume 55 of the Proceedings of the Royal Society as 'On the effect of magnetisation upon the dimensions of wires and rings of annealed iron'.

Reference number

PP/23/14

Earliest possible date

1894

Physical description

Ink and graphite pencil on paper

Page extent

11 pages

Format

Manuscript
Diagram
Photograph