The news & observer. [volume] (Raleigh, N.C.) 1894-current, 1905-07-19
TantaIum Minerals for In
candescent Lamps.
INHENDERSON COUNTY
All of the Zircon of 1904 Obtained
from this State, and Large GUAM
titles of MonazIte. Fgr EIec-
trio. kernst and Wells
bach Lamps.

North Carolinians will be deeply in.
terested in the report which DR.. JOSEPH
Hyde Pratt. Of the United States Geo,
logical Survey, has recently prepared
on the production of monazite. zireon
gadolinite and columbite or tantalum
minerals. These minerals are all min
ed for siRlilar purpose. that is. fol
incandescent lamps The ziucon i
county, this State, and the three
States in which tantalum minerals
may be mined to any large extent are
North Carolina, Connecticut and South
Dakota.
The use IF tantaIum in the CONNER
cial world is due 10 the discovery that
this metal IS capable of .withstaading
the highest temperature obtained IN
an incandeScent light and that il is
sufficiently ductile TO permit its being
drawn into a very fine wire which
shows little tendency TO break when
heated by the electric current. The
experiments made in the chemical Ia
boratory of Siemens & Haiske, manu-
facturerS of incandeScent lamps
which led to the discovery of these
qualities in tantalum and in the in
vention OF the tantalum lamp are
clearly recalled by DR.. Pratt.
The localities in North Carolina,
Connecticut. and South Dakota where
tantalum minerals have been or may
be found are enumerated and list
is given of minerals that contain tam
talum. together with their chemical
composition and the localities where
they have been discovered. The guam
tity Of tantaium required in the manu-
facture of the lamps is exceedingly
small however. so that few tons of
these minerals viii go long way in
supplying he demand for the metal
OF these tantalum minerals the
production of monazite is at the pres
ent time of the greatest Importance,
as the others have all been produced
in much smaller quantities. With the
exception OF portions OF the monaZlte
and the columbite which We're export
ed 10 Germany. all of the output OF
these minerals was used in the United
States. The demand for monazite is
constantly increasing. while there is
but little increase in the use OF Zircon
and gadolinite. The demand for column
bite and other tantalum minerals has
arisen only during the last year, and
il is impossible 10 predict the ex-
tent 10 which those may be used.
The commercial value of monazite
IL TIE. PICSSAiOc VI - AAAOiA
is used in the manufacture of the
mantles for the Welsbach and other
incandescent gaSlights. The Wells
bach light consists OF cylindrical
hood or mantle composed of fibrous
network of the rare earths, the top
OF which is drawn together and held
BY a loop of platinum wire. The ex-
act composition of the hoods is not
generally known, as il is a trade Sc
cret but they are composed largely
OF thoria with smaller quantities of
the Ianthanum and didvmium oxides.
The output OF Zircon and gadolinlte
is employed almost exclusively in the
manufacture of chemical compounds
that are utilized in the construction
OF the glover of the Nerst lamp. The
Zircon is mined for its Zirconia con-
tent and from the gadolinite is OBJ
tanned yttria, these two oxides repre-
senting the principal ores used in the
glover The. zircon is obtained entire
" from the deposits in Henderson
county. y. c. and the gadolinite is
obtained from Liano county. Texas.
DR.. Pratt describes the occurrences of
gadonnite discusses its chemical COM
position. gives analyses of specimens
from Texas and Colorado. enumerates
and describes the principal yttrium
minerals. and closes his discussion OF
gadolinite with description OF the
Nernst lamp.
During 1884 the production of