arago's

Updated: June 27, 2025

To Faraday these experiments explained the phenomenon of Arago's rotating disk, the disk inducing the current from the magnet, and, in reacting, deflecting the needle. To prove this, he constructed a disk that revolved between the poles of an electro-magnet, connecting the axis and the edge of the disk with a galvanometer.

Edward Huntington Williams - A History of Science — Volume 3

Faraday's invention of the first dynamo is interesting because at the same time he made the invention he solved a problem which up to his time had been the despair of the ablest physicists and mathematicians. This was the phenomenon of Arago's rotating disc.

John Lord - Beacon Lights of History, Volume 14 : The New Era; A Supplementary Volume, by Recent Writers, as Set Forth in the Preface and Table of Contents

A few years later he became interested, like all the scientists of the time, in Arago's experiment of rotating a copper disk underneath a suspended compass-needle. When this disk was rotated rapidly, the needle was deflected, or even rotated about its axis, in a manner quite inexplicable.

Edward Huntington Williams - A History of Science — Volume 3