Soap

"T 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 algæ, or seaweeds.

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 Claire.

"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 coöperation 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 tallow.

"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 economical.

"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 substance."