Evening journal., 1903-09-10
NATIVE PLATINUM.
TIE "NobIe' Metals Extracted From
This Peculiar Substance.


On the slopes OF the Ural mountains
and in Brazil, California, Australia,
Canada and many other countries pc
"uliar substance known as native platl-
mum IS found This is an alloy Of the
metals platinum, palladium, iridium,
csnlium, rhodium and ruthenium, to
rather with a little gold and iron. All
cS these except the last mentioned arc
tre noble" metgls. They do not tor
nish III the air and are not soluble in
0ny single acid. The most plentiful
metal occurring In native platinum is
that from which it takes its name.
This metal is Of a grayish color and
with one exception is the heaviest sub
stance known. It's fusing point is ex-
tremely high, and this property, TO-
gethcr with its freedom from tnrnlsh-
ing. causes It to be largely used for the
manufacture Of crucibles and other
vessels required by scientists 10 stand
a very high temperature. II is also
sometimes used as a substitute for gold
In photography, and when deposited in
a thin film on the interior Of the tubes
Of telescopes IL forras dead black
surface, which prevents the light from
being reflected by the polished sides.
Palladium Is Of lustrous white
color II IS the most easily fused OF
the metals found in platinum one, and
can even be volatllized A curious
quality which this metal possesses is
that when heated to redness it is
porous TO hydrogen gas, allowing It 10
pass through somewhat in the snme
manner that blotting paper permits the
passage of water. The silvery white
color Of palladium and its freedom
from furnishing render it useful for
making scales and division marks on
scientific instruments. A mixture Of
this metal with mercury Is sometimes
used for filling teeth Osmium is q
metal which possesses two remarkable
pBoperties-it is the most refractory
Of the metals, resisting fusion at the
most intense heat, and it. is also the
heaviest substance known. being twen-
ty-two and a half times heavier thAn
water Together with iridium, 1t oc-
ours principally IN peculiar variety Of
nntive platinum called osmiridium,
This mineral differs from ordinary
platinum ore in that it contains a
larger proportion of osmium and irid-
ium than platinum. Osmiridium is
found in small particles, varying in
weight from one-sixth 10 one-third Of
a grain. These particles are extremely
hard and. are used for pointing non
wearing pens.
Metallic iridium possesses n white
steel-like appearance. The knife edges
of delicate balances and other bearings
which require extreme hardness are
often made Of It. An alloy of 10 per
cent iridium and 90 per cent platinum
has been found TO be very httle affected
IN volume by changes Of temperature
and Is the substance Of which the
standard meter kept in the internatien-
al metric bureau at Paris is made.
Rhodium and ruthenium are metals Of
little practical use. The former occurs
in platinum ore TO the extent Of TO G
per cent. The latter is found only in
osmiridium and averages about per
cent OF that mineral The metal which
ranks next to platinum in price Is zir
conium, which occurs in hyacinth and
some other rare minerals. Uranium Ii
remarkable for its high atomic weight
the heaviest known.-Chambers' Jour
nal.