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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136 SCIENTIFIC INVESTIGATIONS ON PHOTOGRAPHY.
change upon inorganic bodies exposed, at the same time, to the
influence of the chemical rays.
6. Hence actinism, regarded at present merely as a pheno-
menon different from light, stands in direct antagonism to light.
7. Heat radiations produce chemical change in virtue ot some
combined action not yet understood. . .
8. Actinism is necessary for the healthful germination ot seed;
li<rht is required to excite the plant to decompose carbonic acid;
caloric is required in developing and carrying out the repro-
ductive functions of the plant. .,
9. Phosphorescence is due to actinism, and not to light.
10. Electrical phenomena are quickened by actinism, and
retarded by light. . ...,
Numerous other points of minor importance wiU present
themselves on studying the facts described. Without venturing
to obtrude my own views, I now leave the subject for that lull
investigation which it will, I trust, receive, as promising beyond
all others to enlighten us on those curious phenomena which
appear to link together the organic and the inorganic worlds.