<h2><SPAN name="CHAPTER_XXVI" id="CHAPTER_XXVI"></SPAN>CHAPTER XXVI.</h2>
<h3>ELECTRICAL PRODUCTS—BLEACHING-POWDER.</h3>
<p>Another industry that has assumed large
proportions at Niagara Falls, owing to the vast
quantity of electricity produced there, is the
manufacture of a commercial product called
bleaching-powder, or chloride of lime. Every
one knows that chloride of sodium is simply
common salt, so extensively used wherever
people and animals exist. Simple and harmless
as it is, while it exists as a compound of the
original elements, when separated into those
elements they are each very unpleasant and
even dangerous substances to handle. Salt is
one of the most common substances in nature.
It is found in many parts of the world in solid
beds, and is one of the prominent constituents
of sea-water.</p>
<p>Salt is a compound of chlorine and a metal
called sodium. Sodium in its pure state has a
strong affinity for oxygen, so much so that
when a lump of it is thrown into water it takes
fire and burns violently with a yellow flame.
Chlorine, the substance with which it unites
to form common salt, is a greenish-colored gas,<span class="pagenum"><SPAN name="Page_219" id="Page_219"></SPAN></span>
the fumes of which are very offensive and
very dangerous even to breathe, if the quantity
is very considerable.</p>
<p>It is a curious fact in nature that two such
substances as chlorine and sodium, both of
them so difficult and dangerous to handle,
should unite together to form such a useful
and harmless compound as common salt. The
important element in bleaching-powder is the
chlorine which it contains. It is extensively
used in the manufacture of paper and in all
other materials where bleaching is required.
The object of combining it with lime, forming
a chloride of lime, is simply to have a convenient
method of holding the chlorine in a
safe and convenient manner until it is needed
for use.</p>
<p>The chemical works at Niagara Falls manufacture
bleaching-powder on a very large
scale. The part that electricity plays is to
separate the chlorine from the sodium as it
exists in common salt. At the works I was
first taken into a room where a large quantity
of salt was stored. A belt with little carrier-buckets
on it picked up this salt and carried it
into another room, where it was thrown into
a vast mixing-vat containing water. The salt
was mixed with water until a saturated solution
was obtained. In a large room, covering
one-half acre or more of ground, were assembled
a great number of shallow vessels,<span class="pagenum"><SPAN name="Page_220" id="Page_220"></SPAN></span>
about 4 by 5 feet square and 1 foot deep.
These vessels were sealed up so that they were
gas-tight. Communicating with all of these
vessels were pipes connecting with the great
tank containing the saturated solution of salt.</p>
<p>From the top or cover of each vessel is a
pipe running to a main pipe that carries off
the chlorine gas into another room as fast as
it is formed. Through each one of these vessels
a current of electricity passes; the whole
system consuming about 2000 horse-power.
The electric current, as it passes through the
brine, separates the chlorine from the sodium,
the chlorine passing in the form of gas up
through the pipes, before mentioned, into the
main pipe, where it is carried into another
large room and discharged into a system of
gas-tight chambers. Upon the floor of these
chambers is spread a coating of unslacked
lime ground into a fine powder. The lime has
a strong affinity for the chlorine gas and
rapidly absorbs it, forming chloride of lime.
When the lime is fully saturated with the
chlorine the gas is turned off from that chamber,
which is then opened up and the chloride
taken out for shipment. A new coating of
lime is now spread in the chamber and the gas
is turned on and the process repeated.</p>
<p>There are a number of these chambers, so
that the operation in all of its phases is going
on continuously. The room where the chlo<span class="pagenum"><SPAN name="Page_221" id="Page_221"></SPAN></span>rine
gas is formed is thoroughly ventilated, a
precaution which is very necessary in case any
one of the vats should spring a leak, as they
sometimes do.</p>
<p>In each one of these vats where the electrolytic
process is going on there are two
products constantly passing off; one, as before
mentioned, is chlorine gas, and the other
caustic soda in solution. The solution in the
vat is constantly being renewed by the saturated
solution of salt from the reservoir before
mentioned. There is one stream continuously
coming into the vat and two going out,
caused by the decomposing power of the electric
current. The solution of caustic soda is
carried to large evaporating-pans, where the
water is driven out of it, leaving the caustic
soda in dry, white sticks of crystalline formation.
In this process the electric current,
which comes from the power-house with an
energy of 2000 horse-power, has to be transformed
twice; first, to bring it to the proper
voltage for the work of decomposition, and,
secondly, to change it from an alternating to
a direct current, by which all electrolytic processes
are carried on.</p>
<p>You will notice that the electrical energy
expended in this establishment is double that
used in the manufacture of carborundum.</p>
<p>The caustic soda, which is one of the products
from the decomposition of salt, is taken<span class="pagenum"><SPAN name="Page_222" id="Page_222"></SPAN></span>
to another establishment, where, by still another
electrical process, metallic sodium is
manufactured. The process here being a
secret one, the writer did not have the privilege
of examining the details.</p>
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