Paper, 'Report on the capacities, in respect of light and photographic action, of two silver on glass mirrors of different focal lengths' by C [Charles] Pritchard

Description

Pritchard writes: 'In May of last year, I was requested by a Committee on stellar photography, appointed by the Council of the Royal Society, to examine the comparative photographic capacities of two silver on glass mirrors, each having an aperture of 15 inches, but of different focal lengths, viz., 80 inches and 120 inches respectively. In the present report these will be designated by the symbols 15/80-inch and 15/120-inch. The mirrors in question were provided by the generosity of Dr Warren de la Rue. Various unforeseen difficulties incidental to pioneering in a science still in its infancy have intervened, unavoidably impeding the progress of the enquiry.'

Annotations in pencil and ink. Includes two drawings of photographic plates of stars and corresponding engraved prints.

Subject: Optics

Received 18 April 1888. Read 3 May 1888.

A version of this paper was published in volume 44 of the Proceedings of the Royal Society as 'Report on the capacities, in respect of light and photographic action, of two silver on glass mirrors of different focal lengths'.

Reference number

PP/12/9

Earliest possible date

1888

Physical description

Ink and graphite pencil on paper

Page extent

24 pages

Format

Manuscript
Drawing
Print