Washington sentinel., 1854-02-10
Gold Assaying i'm south America.

The process of gold assaying, amongst the
native miners Of South America, is very simple.
A fragment of quartz is pounded, and rubbed
to powder between two pieces OF granite. A
bullock's horn, of black color, is the only assay
instrument. It is cut longitudinally into two
equal pieces, partly on the curve, so that one
half forms a kind Of long spoon, the inside of
which being polished The powder being
placed in the spoon, the water is poured IN 1t
and shaken, and then poured of. second
and third water being applied, nothing is left
but the coarser particles at the bottom, and at
one edge Of them, conspicuous on the black
horn, is seen fringe of gold powder, if gold be
present With keg of water at his back, and
his spoon in his wallet, and little parched
meal, the mine hunter wanders among the bar
rem rocks in search OF treasure, which he sells
when discovered, and seeks another; the
claims of labor being practically regulated BY
natural aptitudes. The man who buys the
mine digs the ore, breaks it up into the size of
walnuts, loads it into hide sacks borne on
mules, and sells it to the "benefciador," or
benefter, in the valley below, who passes it
through the MILL Having settled upon small
stream, with fall from four to five feet, he
builds up two walls to enclose it on each side,
and back wall to form small reservoir, with
a spout and plug to let out the water at his
pleasure. Over the side walls, with consider
able labor, he contrives to lay a fiat circular
granite stone, some five feet in diameter, with
a hole of some fifteen inches through the md
die. The middle of the stone is hooped round
with slaves, which stand up eighteen inches IN
the form of tube.
The outside is surrounded with similar
slaves, so that water-hght circular trench IS
formed with granite bottom. Through the
central hole is passed the straight stem OF a
tree, shod with an iron pivot, standing on an
iron shoe, fast to block below. The upper
part Of the tree is steadied in a beam above,
supported by two upright posts. Through the
middle of the vertical shaft is a horizontal hole,
with a horizontal shaft projecting on each side.
In this horizontal shaft, at nearly the level OF
the foot below, are affixed in q circle, like the
spokes Of a wheel, number of wooden spoons,
about three feet in length. To the horizontal
arms above are tied by raw-hide cordage q
sort oflarge flag paving stones, with their faces
bearing on the fiat granite below. The water
being turned on the spoons, the paving-stones
are drawn round by the motion OF the shaft,
and grind the quartz. An Improvement on
this is to use two vertical rollerstones eighteen
inches thick and FIVE feet in diameter, with
circular hole in the centre, through which the
nOrlZOntal SnaII OF ;lrHl passes, dAu AohSoo eSi
round As the stones vary in their speed on
the inner and outer edges, there is grinding
as we'll as crushing process. When the ma
chine is at work, quantity of quicksilver is
thrown into the trench, and the quartz with it.
A small stream of water runs in, and at one
portion of the rim there is hole for it to run
over, which it does, carrying the floating mud
with it. As it runs over, it falls into goat
skin, with quicksilver at the bottom. Out Of
this goatskin it falls into a second, with more
quicksilver, and so on from one to another,
according to the amount Of fall. When the
quicksilver is supposed to be saturated, the
mill is stopped, the quicksilver is taken out of
all the receptacles and poured into linen bag
Of fine texture and three or four thicknesses.
The quicksilver is squeezed through this bag,
and the. thickening amalgam is finally rammed
down with sort Of rollingpin.