Paper, 'On the rate of propagation of the luminous discharge of electricity through a rarefied gas' by J J [Joseph John] Thomson

Description

Thomson writes: 'Though the determination of the velocity of propagation of the luminosity which accompanies the electric discharge through gases might well be expected to throw considerable light on the means by which the discharge is effected, as far as I can find, no attempts seem to have been made in this direction since Wheatstone, in 1835, observed the appearance presented in a rotating mirror of the discharge through a vacuum tube 6 feet long; he concluded from his observations that the velocity with which the flash went through the tube could not have been less than 2 x 10^7. cm. per second. This very great velocity does not seem to be accompanied by a correspondingly large velocity of the luminous molecules, for von Jahn (Wiedemann’s ‘Annalen,’ vol. 8, 1879, p. 675) has shown that the lines of the spectrum of the gas in the discharge tube are not displaced by as much as 1/40 of the distance between the D lines when the line of sight is in the direction of the discharge tube. It follows from this, by Doppler’s principle, that the particles when emitting light are not travelling in the direction of the discharge at the rate of more than a mile a second, proving at any rate th at the luminosity does not consist of a wind of luminous particles travelling with the velocity of the discharge.'

Annotations in pencil and ink.

Subject: Physics

Received 2 January 1891. Read 15 January 1891.

A version of this paper was published in volume 49 of the Proceedings of the Royal Society as 'On the rate of propagation of the luminous discharge of electricity through a rarefied gas'.

Reference number

PP/17/5

Earliest possible date

1890-1891

Physical description

Ink and graphite pencil on paper

Page extent

21 pages

Format

Manuscript