The Saint Paul globe. (St. Paul, Minn.) 1896-1905, 1898-08-14

nitrate fields. AS to where the nitrate
comes from there are number Of
theories.
One Is that the desert was once the
bed Of an inland sea, and that the
nitrate came from the decaying of the
heterogeneous sea weed. Another theory
is that the ammonia rising from the
vast beds of guano on the islands off
the coast was carried by the winds
over the range of hills near the sea
and there condensed, settled and unit
ed with other chemicals of the soil to
form the deposits, and still third is
that the electrical discharges of the
Andes combine with the elements of
the air to make nitric acid. This acid
was carried down through the ages in
the floods Of the Andes and was de-
posted on these beds in the form of
nitrate Of soda. None of these theories
are entirely satisfactory, and as yet
no one has absolutely solved the prob
lem as to whence the nitrate comes.
HOW NITRATE IS MINED.
We shall see how nitrate is mined
by visit Of the great pampa Of Tam
rugal. This pampa or field has sixty
miles of of1cinas and nitrate fields.
A railroad has been built through it
to carry the nitrate to the seacoast
at Iquique, and upon it has grown up
vast factories, towns of corrugated
iron huts, in which the tens Of thou
sands of wOrkmen employed in the
business live and the homes of the
scores Of wel1-educated Europeans who
live here and manage the properties.
Leaving Iquique, the railroad carries
you UP the hills and brings you right
into the nitrate fields You are soon in
a plain about twenty miles wide with
low hills rising upward on the right
and the left. On the side Of this plain
nearest the sea the earth looks as
though it had been plowed by giants,
and 1t lies in mammoth clods of all
shapes and sizes. This is the nitrate
fields which have been or are being
worked. The rest Of the land is bleak,
bare sand. There is no vegetation and
no sign of life Of any kind.
All is sand, salt rock, and amid the
clods nitrate rock, which is called ca
liche. 1t is a soluble rock of different
colors. In some places it IS almost
white and looks like rock salt In
others it is yellow, and in others all
shades of gray, lemon, violet and green
The strata of nitrate usually lies two
feet or more under the earth and there
Is often a salt rock or conglomerate
above it. The method Of getting it out
is to bore a round hole about a foot
in diameter through the upper crust
and to extend it down for a few inches
into the soft earth below it. Now into
this hole boy is let down. He SCOOPS
out a pocket for the blasting powder
and arranges the fuse. He is then
pulled out and the fuse is lighted An
explosion follows. A great yellow cloud
of smoke and dust goes UP into the
air and the earth is broken up for a
radius of about thirty feet about the
hole. The nitrate rock is now dug off
with picks and crowbars. 1t is broken
into pieces of thirty pounds or less and
! is loaded upon iron carts to be taken
to the factory Each Of these carts will
hold three tons Of rock and each is
hauled by three mules, the driver sit
ting upon one Of the animals.
AT THE FACTORY.
The caliche or nitrate rock Is taken
in these carts from the fields to the
ofcina or factory. This usually stands
in the midst Of the fields. 1t is a COL
lection of buildings with great smoke
stacks rising above them. It contains
thousands of dollars worth of costly
machinery, vast tanks for boiling the
| nitrate rock crushers like those Of a
snelter to break 1t to pieces and set
| Ting watts In which the liquor con-
tanning the pure nitrate Of soda is left
until it has dropped its burden of val
liable salt. The nitrate rock Of the
| aqua Santa HelQS as we saw 1T blasted
| out Of the earth has only about 40 per
| cent of nitrate Of soda in it. The nj
trate sent to the markets is from 95
to Sc per cent pure and the rock must
be so treated as to bring about this re-
suit. This is done by boiling the rock
just SO much and no more.
The cruShers reduce the caliche to
pieces about two inches thick, and it
is then taken to the boiling tanks,
which are situated in a building per
haps fifty feet above the ground. These
tanks are each big enough to form a
bath tub for an elephant. They are
twenty -four feet long, nine feet wide
and eight feet deep. In them there
arc coils of pipe into which steam 10
running. raising the temperature of the
fluid in the tank to any desired MONT
The caliche is carried in cars m on
inclined railway and dumped into ~.
tanks. Then water is admitted ana is
allowed to flow from tank to tank in
such way as to act to the best ad-
vantage on the salts within. The nj
trate Of soda will remain in solution
] at lower temperature than other