A Manual Of Photography
Forfatter: Robert Hunt
År: 1853
Forlag: John Joseph Griffin & Co.
Sted: London
Udgave: 3
Sider: 370
UDK: 77.02 Hun
Third Edition, Enlarged
Illustrated by Numerous Engrabings
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THE PHOTOGRAPHOMETER.
157
Section II.—Instruments for Measuring Actinic
Variations, &c.
THE PIIOTOGRAPIIOMETER.
M. Claudet has devised the Photographometer and the
Dynactinometer for measuring the intensity of the actinic
radiations. These are both most ingenious instruments, the
operations of which will be rendered intelligible by the following
description :—
The accompanying figure (20) shews the photographometer
complete. The sensitive plate or paper is placed in a dark box,
20.
which is fixed in an independent frame, as shewn in Figs. 21
and 22, and as placed in its position at F in the adjoining cut.
A black silk webbing being fixed to the moveable plate seen at
the head of the instrument, and strained over two rollers, R, R,
it will be evident that the sensitive plate is screened from light
until the moveable slide falling down the inclined plane passes
21.