(Paris, Crochard, 1820). No wrappers as extracted fron 'Annales de Chimie et de Physique', Volume 15 (2e Series). Pp. 93-102.
First appearance of this importent paper in which Arago gives an account of his discovery of how iron and steel could be magnetized by the action of the voltaic current, THE FIRST STEP TOWARDS THE ELECTRIC TELEGRAPH.
"Arago .... made several important contributions to electromagnetism on his own. On 20 September 1820 he announced the discovery of the temporary magnetization of soft iron by an electric current, which suggested to Ampère a theory about the nature of magnetic "currents" and provided the technological key to the electric telegraph. Ampère calculated that the magnetic power could be multiplied by twisting the current-carrying wire into a helix, and with Arago he carried out the first experiments on primitive solenoids. In his historical articles Arago was always careful to credit Ampère with the major share of this discovery, which ultimately depended upon Ampère’s mathematical theory."(DSB).
Arago formed a close freinship with Fresnel,whose views on the nature of light he ardently supported. He assisted Fresnel in some of his most importent work and made original discoveries in the same field.
Magie "A Source Book in Physics", p. 443 ff.