Paper, 'Observations on the radiation of light and heat from bright and black incandescent surfaces' by Mortimer Evans

Description

Evans writes: 'In the course of an investigation into the nature of carbon filaments, such as are ordinarily used in the construction of incandescent lamps, my attention was arrested by certain variations in the amount of light emitted from filaments which were, to the best of my belief, of similar nature and composition, but which, when tested under precisely similar conditions, gave the most anomalous results. I was also struck with changes which occurred to a greater or less degree in the light yielded by certain lamps when re-tested subsequent to a shock of over-incandescence, or long continued hard running at a high temperature; the light yielded after this occurrence (indeed the light yielded by any lamps that had been much used) I found to be invariably lessened both in quantity and brightness, and to require a considerable increase in the energy supplied to it to produce from the same filament the light it originally gave.'

Annotations in pencil and ink. Includes three graphs and three corresponding prints.

Subject: Optics / Radiation

Received 3 February 1886. Read 18 February 1886. Communicated by Lord Rayleigh [ John William Strutt].

A version of this paper was published in volume 40 of the Proceedings of the Royal Society as 'Observations on the radiation of light and heat from bright and black incandescent surfaces'.

Reference number

PP/8/12

Earliest possible date

1886

Physical description

Ink and graphite pencil on paper

Page extent

18 pages

Format

Manuscript
Diagram
Print