The morning news. [volume] (Savannah, Ga.) 1887-1900, 1897-11-20
LIGHT STORED IN METAL.
A Great Many Substances Generate
Rays in Absolute Darkness.

From an Exchange.
Another startling discovery has been
made in the realm Of invisible rays. and
independently verified by different experi-
menters. namely, that many substances
which We have been in the habit Of re-
garding as inert are constantly emitting
invisible rays In the absence of other light.
which rays possess actinic power and
therefore are capable Of affecting sensitive
Photographic plates. Some six months ago
the eminent French investigator, Becque-
rel, discovered that the element uranium
when exposed to brilliant light stored up
during this period energy which was either
transferred into rays Of other kinds, or
else emitted in its original Incident form,
when the substance was placed in abso-
lutte darkness. Moreover, these rays pos
sessed remarkable, power of penetrating
light, Opaque subs tances, X-ray like. DR..
Russell In a paper recently read before
the Royal society of London, described how
in repeating Becquerers experiments he
discovered that this particular action is
by no means confined to uranium salts,
but that many of the metals and other
bodies, such as wood, charcoal copai
straw, etc, possess il In a marked degree
The radiations from these bodies how
ever, differ in one very important par
tIcular from those given out by the uran-
ium compounds. While the latter readily
pass through glass, the former are com
pletely stopped by 1t.
Starting with the metals mercury. zinc
magnesium, cadmium, nickel, aluminium
pewter, fusible metal, bismuth, tin, CO.
bait and anthony. he found that all these.
after a weeks exposure near a sensitive
plae In the dark, every precaution being
taken to exclude extTaneous light pro-
duced a distinct effect upon the plate,
while gold, iron and copper only showed a
very slight effect. The fact has been
known for a long time that certain sub
stances were placed in contact with a
sensitive film for a long time will show
traces Of their outline in the DEVELOPMENT
Of the plate. This phenomenon has never
been satisfactorily explained. DIR. Rus
sells results, however, are not based on
this principle, as In the instance a polish
ed surface of zinc with a design scratched
on 1t gave distinct image of the mark
ings when not touching the plate. and
even when. thin screens of gutta percha
or celluloid were interposed between the
sensitive plate and the zinc surface. In
another set of experiments, cardboard pill
boxes, used for inclosing certain sub
stances before the experiments were
found to be quite active themselves in
emitting these remarkable radiatiohs. i'm
printing a most distinct image OF them
selves
Different qualities of cardboard give va
rying results, the better kinds acted but
family, while cheaper kinds, such as
straW-board, were very active. In the
same way certain printing inks gave very
good impressions on the plate while 9TH
eTs were altogether inert
As regards the conditions affecting the
emission of these radations 1t Is known
that heat increases their activity, and the
water vapor IN no way assists their ac-
ton. Their source is a mystery Some
form Of potential energy stored up in the
active bodies possesses the power of gem
Grating, through what medium has not
even been surmised. rays quite as remark
able as the Roentgen rays, and possessing
in a limited degree many of their char
acterlstic properties. Probably their ma
ture is akin to what has paradoxlcally
been styled dark light"