Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1890-04-20
The Government Survey Locating
Mines for Gold Hunters.
HOW THE YELLOW STUFF is FOUND.
A Corner in Platinum Threatened and a
Plea for Dakota Tin.
PHOTOGRAPHIC FILMS OF STONE
CORRESPONDENCE OF THE DIsPATcH.I

bHlS CouHtFyy Lndt give PTomlSe Oi yellow
wealth. 1t is generally supposed that gold
is only found in stray places and isolated
localities, whereas the fact is that it is the
most widely distributed of all metals. Every
gravel-bank and sand bar is mine of it,
the only trouble being that there is not
enough of the metal present to pay for the
process of separating it. THERE'S not a cart
load of sand on the Atlantic and Pacific
coast that will not yield at least ''color. -
Philadelphia Is built on soil that would
very nearly, if not quite, pay for panning,
Just for the gold in it. The yellow mineral
is everywhere, almost. And why?
Simply because all of it found in the
world was originally deposited by sea
water during those ages when the waves of
ocean overfowed the continents. Under
certain chemical conditions sea water will
dissolve gold and hold it in solution, and
thus it happened that during the epoch re-
ferred to the ocean was tincture of this
metal. Gold was one OF the elements enter
ing into the original composition of the form
ing earth crust, and the sea water held it sus-
pended for time and finally deposited it,
as if with the intention of putting coat of
gliding on the globe.
THE CALIFORNIA FIELDS.
But In some places conditions were more
favora BILE than in others for the reception of
the deposit. For instance, the California
hills, in the process of formation, were by
causes geological all erumpled up, so that
cracks were left everywhere. In these gold
collected with other minerals deposited in
the same way, and in this manner were
formed what are now called gold-bearing
veins.
It is believed by geologists that all the
gold in the earth is on the surface of the
globe or very near it. Quite otherwise is it
with silver, which was all thrown up Or
iginally from the earth's bowels by volcanic
action. Just as occurred in the case of gold,
the floods of ocean took up the silver and
deposited it wherever circumstances were
favorable, as In Nevada, where one silver
bearing crack in the rocks, at Virginia
City, has already been mined to the depth
of 2, 200 feet without getting anywhere near
the bottom.
The processes employed by the Geological
Survey in the examination of rocks are
most interesting. To begin with, chip OF
the stone to be Investigated is ground down
on one side with an emery wheel until it is
an absolute plane perfectly polished. The
polished side is then attached to piece OF
glass and the other side of the stone chip is
applied to the emery wheel until the chip
itself is ground all away, save only a film
of inconceivable thinness. This film is
finally removed and placed upon a little
glass "slide," and now the stone is ready
to be examined. f9 -
PHOTOGRAPHS OF THE STONE.
For this purpose it is put under power
full microscope, in which an arrangement is
provided for polarizing light. Looked
at through the instrument in the ordinary
way, the film of stone, which resembles q
mere blot of discoloration on the glass to
the naked eye, is exhibited merely magni-
fed enormously. But when by the turn of
a screw the light is polarized, the object is
suddenly dressed in the most gorgeous col
ors of the rainbow, each element found in
the rock taking on . hue OF its own-brill-
liant blue, red, green or what not Photo
graphs are taken of the little films of stone
with micro-camera. 1t only remains now
to paint the photograph with water colors
precisely as the same object appears to the
epe through the microscope, with the aid of
polarized light and you have a permanent
picture record of that particular kind of
rock.
Something happened the other day that
shows one use of a practical sort to which
the study of rocks may be put. Out in the
wild West mailbag was emptied of valua-
ble contents by parties unknown and filled
with stones. The loss was not discovered
until the bag reached its destination, and no
one had any notion where the theft was
committed within a thousand miles of the
IL
rocks, and he said at once that there was
only one place In the United States where
such were to be found. He told where the
place was, and a detective going there-it
was 45O miles away-found two Cinnamon
at work in an isolated spot where, it was
subsequently remembered, the robbed train
had stopped for water. He promptly
charged them with the crime, and they were
so taken by surprise that they confessed it.
So muc1 for rocks.
-. PLATINUM AND TIN.
Platinum has risen 100 per cent in value
within the last year, and no reason seems to
exist for supposing that it will ever go
down again.
''Four-ffths of the platinum that sup
plies the world is obtained from two mines
at Nishnee-Tagilsk and Goro- -Blagodat, in
the Ural Mountains, Siberia" said DIR.
David T. Day, of the Geological Survey,
Yesterday. platinum and gold are usually
found together. The deposits of the Qral
are mined, not for platinum primarilv,sb but
for the more precious yellow stuff-the
platinum is sby-product.' But now the
gold has become scarce and they are forced
to depend to a greater extent upon the
platinum for their profits. OF that metal
happily, there is plenty left. Laborers are
also scarce, being at work on the Trans
Siberian Railway. At present, also, the big
dealers are buying up all the old platinum
they can lay their hands on, in anticipation
of further rise in price, so that corner
seems to be arriving in the commodity.
This accounts for the RISE"
The capitalists interested in the develop
ment of the great Dakota tin lodes are max
ing tremendous effort to have protective
duty placed upon that metal. They ask ten
years of such defense against foreign COM
petition, at the end of which time they are
willing that the tariff shall be removed and
promise that the wonderful mines of the
Black Hills will supply all the tin that this
can use. These tin mines, they as
sert, will be the most productive that the
world has ever seen. Harney Peak and the
rocky crags in its neighborhood are simply
mountains of tln-much OF the ore being
composed of this valuable |
mineral. As things are now, they are not
in position to compete with the tin brought |
over from Singapore and Penang, which is
mined by 400, 900 coolies and Malays at al |
most no wages day. RENE BACHE.
All Sorts and oudifIons of Mon