The Washington times. [volume] (Washington [D.C.]) 1902-1939, 1903-07-19
THE DISCOVERY OF
POLONIUM AND RADIUN
Nine. CuTie Tells of the Part Played by
Herself and Husband.

in The Independent" One is the share
which she and her husband had respec-
lively IN the famous discovery OF DO
lonium and radium. AS long ago as 1893
she had found that salts of thorirr
emitted substantially the same peculiar
radiations as uranium compounds A
German. Schmidt seems to have hit
upon the fact simultaneously, 5us. so
far as the Paris chemists were con-
cerned. Nine. Curie alone deserves the
credit OF that discovery II was then
noticed that a large number OF natural
minerals. which are mixtures OF several
salts, but which contained either ra-
dunn or thorium, were radioactive. At
first il was believed that one or the
other OF these two metals was RESPONSE
bic for the phenomenon. Nine Curie
then undertook an experiment which
suggested a different conclusion.
One Of these minerals was chalcolfte.
which is compound Of phosphates Of
copper and uranium. In its native stats
II was about twice as powerful as uran-
ium in emitting what are known az
Becquerel rays. Nine Curie manufac-
tured an artificial chalcolite. putting in
the proper ingredients to insure gen
uineness. but this product failed 70 ex
hibit the same radiating power as the
natural salt. Thus was excited a sus-
picion that some other element was
present in minute quantities in the lat
ter. 1t was at this point that NJ Curie
was tempted to join his wife in the
hunt. Two new elements were elimi-
mated, poIonium, which resembles bis
muth in its chemical properties, and
radium, which is allied TO barium. For
the second of these part OF the hcnor is
due to NJ. Bemont, who assisted In the
research.
A third element has been partially
Identified by NJ Debierne presumably
a Frenchmen, though his nationality is
not mentioned from pitchblende. the
mineral which yields uranium and radi-
um. To this other substance the dis
coverer gave the name actinium- II IS
associated with iron compounds. from
which separation Is exceedingly difficult.
Though extraction has thus far been in
complete. Nine Curie appears-t 10 regard
it as a distinct element.
A local sensation was created in Ber-
lin a few months ago by Prof. Merek-
walds announcement that he had found
a new radioactive substance. He de-
rived it from pitchblende, and was dis
posed to call it 'radio-tellurium-" Nine
Curie believes that this is identical with
polonium, found by her five years ago.
What may prove to be a fourth radio
active element. having the chemical
properties Of lead, has been observed
by Messrs. Giesel. Hoffman. and Strauss
Little information is yet available con-
corning It. or these new elements. radi-
um is the only one which has been iso-
lated from all impurities.
To give an idea OF the difficulty Of ex-
tracing polonium land probably radium).
Nine. Curie says that the mineral in
which it occurs contains also uranium
lead. calcium, copper, bismuth, zinc. CO.
bait, manganese. nickel. vanadium,
anthony. thallium. niobium. tantalium.
arsenic, barium and traces OF Others
A practical use for radium is suggest
ed by the fact that by means OF he
phosphorescence which It excites true
diamonds can be distinguished from
paste. Glass which is made iuorescent
thereby gradually turns brown or violet
What Nine. Curie says about the cause
OF the mysterious properties recently
observed deserves TO be quoted in full:
From the beginning of the investiga-
lions on radioactive substances the
spontaneity of their radiation has been
problem which has had the greatest
gators in physics. Today we are fur
Their advanced in our knowledge Of
radioactive substance. and We know
how 10 isolate one radioactive body OF
great radiant power-radium- BY TAX
ing advantage OF the wonderful proper
ties of radium we have succeeded in
making a profound study Of the rays
emitted by radioactive bodies gener-
ally The different kinds of radiations
which have been studied up to the pres
ent time all present certain analogies
with the groups of rays which exist in
Crookes tubes. with the so-called
cathode rays and with the Roentgen
rays. Similar groups Of rays are also
TO be found in the secondary radiations
produced by Roentgen rays, and in the
radiation from substances which have.
by induction, acquired radio-activity.
while the nature of radiation is &C
tually 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 luminous effects produced.
and the fact that there is a constant
disengagement of heat.
1T has been asked, then, If the energy
thus manifested is created in the radio
active substances themselves. or. rather,
If it is not borrowed by them from
external sources. None OF the numer-
Gus hypothesis which have been found
ed on these two methods OF viewing the
question have as yet received any e1-
detrimental confirmation"