Martinsburg herald. [volume] (Martinsburg, W. Va.) 1881-1920, 1903-04-11
RADIUM PHOTOGRAPHY:
Remarkable Experiments With
New Chemical Metal.
MOST COSTLY OF SUBSTANCES.

Rare and wonderful Metal.
Curious and interesting photographs
20. shadoweraphs, as they might bel
ter be called perhaps taken recently
il tile Photographic department Of the
Massachusetts Institute Of Technology
at Boston illustrate the properties Of
the new chemical metal radlum, one OF
the 50 called radio active salts which
have recently startled the scientific
world by demonstrating that an Y ray
picture can be taken %withoutthe X ray
apparatus. says the New York Mail
and Express.
This remarkable metal, which takes
the form Of powder and Is n OF sew.
eral similar agents obtained BY a series
OF delicate chemical operations FROM
the mineral %pitchblende, gives out rays
having many of the characteristic
properties both Of the cathode and the
X ray. they pass through substances
ordinarily im%pervious to light, and the
pictures taken with them are therefore
practically Identical with those taken
by means OF an x ray machine.
Radium is the most expensive Of all
known substances. its value being liter.
ally many thousand times its weight in
gold. a single pound OF it, if such an
amount were obtainable, would per
haps be worth well over S1,0O0.000. IN
the few grams Of powder used in max
ing the institute pictures, for exam
pie, there Is only about l per cent OF
the substance that actually produces
the picture taking ray, this small guam.
titY being 50 powerful. however. that
satisfactory negatives can be secured
even with 50 short an exposure as fiji.
teen seconds, and in the opinion Of sci
entists who have been Investigating its
properties its power Is practically in.
exhaustible.
Taking a picture with radium Is a
much simpler matter than taking one
with N y ray machine. The powder
is kept in a small box not unlike the
cases In which the old fashioned da,
guerreotypes were framed, with IN in
ner cover OF thin celluloid to hold the
precious substance in place when the
box Is opened and its invisible power
turttea ia the direction of the object to
be photographed. The radium itself is
a harmless. looking yellowish powder,
that can be seen to glow dimly when
the eye of the operator has become ac-
customed to the surrounding darkness.
But the photographer must work in
absolute darkness, for the seemingly
magic rays, although they have slight
Illuminating power, act upon a photo
graphic plate much as sunlight does.
The picture making mechanism con.
sists simply Of q sensitized plate and
the little box of radium, the article to
be photographed being placed between
them, either in direct contact or with
an intervening space of a few inches.
AS with the X ray, the power Of
radium varies with its di~stancelfrom
the object photographed. The nearer
the metal is held to the object the
clearer is the impression aud the short
er the time necessary to secure good
results.
Various theories have been p%ropound-
ed as to the source of the power of
this powder to penetrate substances
Opaque to light. One theory is that
radium sends out countless rays of
very short wave length, which are but
little ~obstructed by cloth, paper, cellu-
loid, flesh and some other substances,
but cannot pass through such denser
media as metals, wood or bone with
anything like the same rapidity. An
other supposes that radium is contin-
ually throwing off little invisible bits
of matter. smaller than the atoms
which were so long considered the lin
it Of material divisibility. Indeed it is
necessary in this case to think of an
atom as divided into two parts. one
charged with positive and the other
with negative electricity. In ~explana-
ton of the radium photograph one
must further picture that these in
finitesimal particles. hurled into space
by the chemical, pass through certain
substances and splash, as 1t We're.
against the sensitiZed plate, which
they thus affect everywhere except
where their passage is retarded by the
denser media. The result is of course
that the outline, or shadow, of the
more opaque portions of the object in
terposed appears in the negative, its
darkness being in proportion to the
resistance offered TO the rays.
Radium apparently keeps its curious
property indefinitely, the storing up
process being as mysterious us the dis
appearance Of the genii in the Arabian
Nights entertainments into his copper
cylinder. Among the pictures taken by
the photographers at the Institute is
one made with nitrate of uranium, an
other Of the chemical substances pro
ducing rays that have this peculiar
penetrating power, although In a much
less degree than the radlum especially
prepared for the purpose. The nitrate
Of uranium used to obtain this negative
had, it so happened, been stored away
for years. But the result WAS a very
fair outline picture, though it was not
ILL.,