Paper, 'On the changes produced by magnetization in the length of rods of iron, steel, and nickel' by Shelford Bidwell

Description

Bidwell writes: 'The earliest systematic experiments on the effects produced by magnetisation upon the length of iron and steel rods were those of Joule, an account of which is published in the “Phil. Mag.” of 1847. The experiments were made with bars 36 inches long, which were placed inside a solenoid 38 inches long; and the variations in the length of the bars when currents of electricity were passed through the solenoid were measured by means of a delicate micrometer, each division of which indicated a change of 1/138528 inch. Using bars of iron and soft steel, he found that their length was increased by magnetisation, the elongation varying up to a certain point as the square of the intensity of the magnetisation, temporary or permanent, of the bar, and he remarked that the elongation was, for the same magnetisation, greater in proportion to the softness of the metal.'

Annotations in pencil and ink. Includes four pages of diagrams of experimental apparatus and results.

Subject: Magnetism

Received 1 April 1885 / 15 January 1886. Read 23 April 1885. Communicated by Frederick Guthrie.

A version of this paper was published in volume 40 of the Proceedings of the Royal Society as 'On the changes produced by magnetisation in the length of rods of iron, steel, and nickel'.

Reference number

PP/8/9

Earliest possible date

1885

Physical description

Ink and graphite pencil on paper

Page extent

77 pages

Format

Manuscript
Diagram