Evening star. [volume] (Washington, D.C.) 1854-1972, 1903-08-07
PoLoNIUM AND RADIUM.
Mime. Curie Talks About Them and
Their Behavior.

From the Indo pendent
Several bits of history new to most read
ers are brought out by Nine. Curie. One is
the share which she and her husband had
respectively in the famous discovery of
polonium and radum. AS long ago as
1898 she had found that salts of thorium
emitted substantially the same peculiar
radiations as uranium compounds. A Ger
man, Schmidt, seems to have hit upon the
fact simultaneously, but, so far as the
Paris chemists were concerned, Nine
Cur1e alone deserves the credit of that dis
covery. It was then noticed that large
number of natural minerals. which are
mixtures Of several Salts but which con-
tained either radium or thortum, were
radioactive. At first it was believed that
one or the other of these two metals was
responsible for the phenomenon. Nine.
Curie then undertook an experiment which
suggested a. different conclusion.
One of these minerals was chalcolite,
which is a compound of phosphates of
copper and uranium. In it's native state 1t
was about twice as powerful as uranium
in emitting what are known as Becquerel
rays. Nine. Curie manufactured an arti-
fetal chalcolite, putting in the proper In
gradients to insure genuineness, but this
product failed to exhibit the same radiat-
ing power as the natural salt Thus was
excited a suspicion that some other ele-
ment was present in minute quantities in
the latter 1t was at this point that M.
Curie was tempted to Join his wife In the
hunt. Two new elements were eliminated,
polonium, which resembles bismuth in its
chemical properties, and radium, which is
allied to barium. For the second of these
part of the honor is due to M. Bemont,
who assisted in the research.
What Nine. Curie says about the cause
of the mysterious properties recently OBJ
served deserves to be quoted in full:
From the beginning of the Investigations
1k;x- ,t,eyfu hn 70 ni ty
of their radiation has been a problem
which has had the greatest interest for all
students and investigators in physics. To-
day we are further advanced In our knowl-
edge of radioactive substances, and
know how to isolate one radioactive body
of great radiant dunn. By TAX
ing advantage of the wonderful properties
OF radlum we have succeeded in making
profound study of the rays emitted by
radioactive bodies generally. The differ
ent kinds of radiations which have been
studied up to the present time all present
certain analogies with the groups Of rays
which exist in Crookes tubes, with the So
called cathode rays and with the Rontgen
rays. Similar groups of rays are also to be
found in the secondary radiations produced
by Rontgen rays, and in the radiation from
substances which have, by Induction, ac-
Quired radio-activity.
while the nature of the radiation is
actually better known than before, the
cause of spontaneous radio-activity re-
mains as much of a mystery as ever, and
this phenomenon is still an enigma for us.
spontaneously active substances, and.
above all, radium, are sources of energy.
The amount of energy to which they give
rise Is revealed to us by the radiations of
Becquerel and by the chemical and lumi-
nous effects produced, and the fact that
there is a constant disengagement of heat.
'It has been asked, then, II the energy
thus manifested Is created in the radio
active substances themselves, or. rather,
If it is not borrowed by them from ex-
ternal sources. None Of the numerous hy-
potheses which have been founded on these
two methods Of viewing the question have
as yet received any experimental confirma-
ton"