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HE ashes of plants that grow on the seashore and in
the waters of the sea itself contain, instead of
potash, another substance possessing almost the same
properties and called soda."
"There are plants, then, in the sea?" asked Jules.
"Certainly, my boy; and most curious ones. Our fields
are not more covered with plants than is the bottom of
the sea; but marine plants differ much from terrestrial
ones. Never do they have flowers, never anything to
compare with leaves, never any roots; they fasten
themselves to the rock by gluing the base of the stem
to it, but derive from it no sustenance whatever. It is
water and not the soil that nourishes them. There are
some that resemble viscous thongs, plaited ribbons, or
long manes; others that take the form of little tufted
bushes, of downy topknots, or of waving plumes; there
are some of pinked strips, others coiled in a spiral,
and still others fashioned like coarse, slimy strings.
Some are olive-green, some pale rose; others are yellow
like honey, and others,
 again, of a bright red. These strange plants are called
algae, or seaweeds.
"For a long time the only way to obtain soda was to
gather such marine plants as were cast upon the shore
by the waves and to cut down the various kinds growing
at the water's edge. As soon as this material was quite
dry it was burned out of doors in a ditch, so as to get
the ashes. But as this method was slow and did not
furnish enough soda to supply what is needed in the
arts, which use an enormous quantity, men of science
set their wits to work to devise more fruitful and more
expeditious methods. To-day soda is prepared from
common salt, the sea furnishing inexhaustible
quantities. Immense factories, each with a large force
of workmen, are occupied exclusively with this work."
"Soda, then, is something very important?" asked
"Yes, one of the most important articles used in
manufacture. Many things of the greatest utility and in
everyday demand need for their fabrication the
co÷peration of soda. The fine, white paper on which you
write, the magnificent colored designs of our calicoes
and other prints, the glass in our bottles and
window-panes, our soap, that invaluable aid to
cleanliness, all these things and countless others
require the use of soda, or of potash, which I will
call its sister, so much do they resemble each other."
"Then potash, too, must be manufactured on a large
scale?" was Marie's query.
"The manufacture of potash stands on a par, in
importance, with that of soda; but potash is always
 dearer because less abundant. The greater part of it is
obtained from the ashes of terrestrial plants. For this
purpose in well-wooded countries such as certain
regions of Russia and North America, whole forest are
cut down and the wood is burned on the spot, out in the
open air, just for the sake of the ashes."
"Do you mean to say," said Marie, incredulously, "that
those enormous fires that consume whole forests are
lighted for nothing but to get the ashes?"
"For nothing but to get ashes from which to extract the
potash. I hasten to add that this prodigality is
possible only in countries where forests are abundant
and the population very sparse. In such regions wood is
of little value, as there are no people to use it for
heating. But in our part of the world, where the
forests are far from sufficient for the needs of
heating, great care is taken not to waste wood thus. In
the forest-covered mountains of the Vosges, for
example, it is the practice, in order to obtain ashes,
to burn only the very small branches, which are of
little value, and the dead leaves.
"The manufacture of potash is conducted in the manner I
showed you a little while ago in our elementary
experiment. First the ashes are boiled in water, and
then the clear liquid is drawn off and evaporated to
the last drop over a fire. The incrustation at the
bottom of the kettle is the potash, which is further
purified by methods that do not concern us here.
"The properties of these two valuable substances, soda
and potash, are nearly identical. Both have a
 beautiful white color when very pure; at first sight
you would take them, in their unpowdered form, for
white marble. Both dissolve very easily in water, to
which they give the odor and taste of lye. Both have a
very disagreeable taste; a tiny piece, less than a
pin's head, placed on the tongue, as I have already
told you, would burn like a red-hot iron and take off a
piece of the skin. Both eat into leather, wool, and
silk; and both dissolve greasy substances. You have
seen this last attribute demonstrated in the use of
ashes in washing; and the same characteristic is found
again in soap, as I will now explain to you.
"Of all the stains that are left upon linen by daily
use, the most frequent, as you know, are grease-spots,
which water alone cannot remove. To take out these
spots they must first be rendered soluble in water by
adding a substance which will give them solubility.
Potash and soda fulfil this condition admirably. But
direct use of these harsh substances is impracticable.
What would become of the washerwoman's hands, rubbing
the clothes with drugs that burn the skin like fire? In
a few moments they would be nothing but one horrible
wound. And that is not all: the linen itself, however
strong it might be, would finally be destroyed by such
prolonged contact with these excessively drastic
substances. Potash and soda, therefore, can in no wise
be employed directly in washing. What is to be done
then? The difficulty is solved by adding another
substance which takes away their formidable strength
without too greatly weakening their solvent effect. To
temper the excessive energy of potash and soda, to
 soften in some measure the two terrible drugs and make
them easy to handle, they are mixed with a greasy
ingredient, sometimes oil, sometimes tallow; and from
this mixture comes soap."
"There is oil or tallow in soap?" asked Emile.
"Yes, my dear boy, and plenty of it. The rest consists
of a little potash or soda. These latter give soap the
power to clean; the oil and tallow preserve the hands
and the linen from a contact which without any
intermediary substance would be very dangerous."
"And yet, apart from the greasy feeling, there is
nothing in soap to show that it has any tallow, still
less oil. Oil runs, and soap does not."
"Oil runs only when alone. Once united with potash or
soda, it ceases to be liquid and becomes a block of the
consistency of cheese. Singular though it may seem to
you, it is nevertheless true that soap is composed of
either soda or potash and a greasy substance, oil or
"Soap for common use is made from soda and oil of
inferior quality, or beef suet or mutton tallow. Let me
tell you how soap in large quantities is made. Into
great vats of boiling water the desired quantity of
soda is dropped, then the due proportion of oil or
grease, after which the whole is stirred constantly to
mix it well together. Little by little the soda becomes
incorporated with the grease, and soap forms and floats
on the surface in a compact layer, which is then taken
off and poured into molds where it congeals in thick
square slabs. These slabs are afterward divided into
cakes of a convenient size.
 "There are two kinds of ordinary soap, white soap and
marbled soap. The first is white throughout, the second
veined with bluish lines. For common use marbled soap
is preferable to the other. Besides soda and grease or
oil, soap of any kind always contains a greater or less
proportion of moisture coming from the water in which
it was boiled. Now, white soap contains nearly half of
its weigh in moisture, while marbled soap contains not
quite a third. Being richer in the ingredients that
really count, marbled soap is for that reason more
"Resinous soap is a kind of soap that contains resin
instead of tallow or oil. This soap is of a yellow wax
color, and its cakes are transparent on the edges. It
makes a great deal of lather on being dissolved in
water, is very strong, and is good for washing clothes.
"Toilet soap is prepared from choice materials and is
perfumed with various aromatics embodied in its