DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.1311#0209
1 76 THE GREAT EXHIBITION
materials for its production. It has opened new channels to commerce, and thus it has
become the means, as well as the mark of civilisation. Almost simultaneous with the
employment of soda, the oils of the cocoa-nut and the palm have been introduced into the
manufacture of soap. The statistics respecting the imports into the United Kingdom and
France, demonstrate the increasing consumption of these oils. The development of the
trade in palm oil has contributed largely to the abolition of the iniquitous slave-trade on
the west coast of Africa, and in many parts of the coast, has entirely suspended it.
Before we proceed to the examination of the separate specimens of the soaps which were
exhibited, a few words may be said respecting the materials employed in their manufacture.
They are, on the one hand, alkalies, and on the other, fatty and resinous substances derived
from the organism of animals and plants, especially tallow, lard, palm oil, cocoa-nut oil,
olive oil, linseed oil, fish oil, and common resin. Although physically and chemically
widely distinguished from one another, fats and oils present numerous analogies. Neither
of these substances is a pure chemical compound; the majority are mixtures in varying
proportions of different chemical bodies, which may be isolated by mechanical or chemical
processes. When this separation has been effected, the isolated substances, which are the
proximate principles of the fatty or oily bodies, though again differing much from one
another, exhibit one common chemical character; when exposed to the influence ot
powerful decomposing agents, they are broken up in a similar manner, yielding on the
one hand an acid, and on the other a neutral body. All fats may be resolved into two
proximate fatty substances, one of which is fluid at the common temperature—it is termed
olein; the other is solid, and is called stearin. The preponderance of one or the other of
these proximate constituents determines the state of aggregation of the fat. The body
usually designated stearine is generally a mixture of the stearin of the chemist and an
analogous body, margarin ; the two substances differing in their relative proportion
according to the source from which the fat is obtained. Thus, the solid fat from sheep
(tallow) contains chiefly stearin; that of the pig (lard) and of olive oil, chiefly margarin; the
solid fat of palm oil is palmitin; that of cocoa-nut oil, cocin. Stearin, margarin, olein,
palmitin, and cocin are all compounds of certain fatty acids, with oxide of glyceryl, and
may be viewed as substances resembling neutral salts, or rather compound ethers. The
changes which all these substances undergo, when submitted to the action of powerful
bases, is well illustrated by the deportment of olein with oxide of lead (litharge). When
boiled with this base, the olein is decomposed into oleic acid and oxide of glyceryl.
The former combines with the base, forming an insoluble soap, called oleate of oxide of
lead (diachylon plaster); and the oxide of glyceryl, separating in combination with water,
forms glycerin (hydrated oxide of glyceryl), a substance having a certain analogy with the
group of bodies termed alcohols. It remains dissolved in the water employed. If olein
is boiled with a solution of potash or soda, oleates of potash or soda are obtained; but being
soluble in water, they remain dissolved together with the glycerin.
The oleates of potash or soda, when separated from the water by processes immediately
to be discussed, are what we call, in common life, soaps. Similar soaps are formed by the
remainder of the fatty acids; for example, stearic and margaric acids. Palmitate of soda,
obtained by boiling palm oil with soda, likewise forms a chief ingredient of many soaps.
Potash and soda, as they occur in commerce, are combinations of the alkaline bases, thus
denominated by the chemists, with carbonic acid, and though by long boiling they could
decompose (saponify) fats, yet the operation is tedious, and the saponification generally
incomplete. It is better to deprive the alkalies of their carbonic acid, which is done by
mixing them with quicklime and water; the quick-lime combines with the carbonic acid,
forming an insoluble carbonate of lime (chalk), and the water retains the potash or soda
in solution, contaminated still with such impurities as the alkalies contained (sulphates
materials for its production. It has opened new channels to commerce, and thus it has
become the means, as well as the mark of civilisation. Almost simultaneous with the
employment of soda, the oils of the cocoa-nut and the palm have been introduced into the
manufacture of soap. The statistics respecting the imports into the United Kingdom and
France, demonstrate the increasing consumption of these oils. The development of the
trade in palm oil has contributed largely to the abolition of the iniquitous slave-trade on
the west coast of Africa, and in many parts of the coast, has entirely suspended it.
Before we proceed to the examination of the separate specimens of the soaps which were
exhibited, a few words may be said respecting the materials employed in their manufacture.
They are, on the one hand, alkalies, and on the other, fatty and resinous substances derived
from the organism of animals and plants, especially tallow, lard, palm oil, cocoa-nut oil,
olive oil, linseed oil, fish oil, and common resin. Although physically and chemically
widely distinguished from one another, fats and oils present numerous analogies. Neither
of these substances is a pure chemical compound; the majority are mixtures in varying
proportions of different chemical bodies, which may be isolated by mechanical or chemical
processes. When this separation has been effected, the isolated substances, which are the
proximate principles of the fatty or oily bodies, though again differing much from one
another, exhibit one common chemical character; when exposed to the influence ot
powerful decomposing agents, they are broken up in a similar manner, yielding on the
one hand an acid, and on the other a neutral body. All fats may be resolved into two
proximate fatty substances, one of which is fluid at the common temperature—it is termed
olein; the other is solid, and is called stearin. The preponderance of one or the other of
these proximate constituents determines the state of aggregation of the fat. The body
usually designated stearine is generally a mixture of the stearin of the chemist and an
analogous body, margarin ; the two substances differing in their relative proportion
according to the source from which the fat is obtained. Thus, the solid fat from sheep
(tallow) contains chiefly stearin; that of the pig (lard) and of olive oil, chiefly margarin; the
solid fat of palm oil is palmitin; that of cocoa-nut oil, cocin. Stearin, margarin, olein,
palmitin, and cocin are all compounds of certain fatty acids, with oxide of glyceryl, and
may be viewed as substances resembling neutral salts, or rather compound ethers. The
changes which all these substances undergo, when submitted to the action of powerful
bases, is well illustrated by the deportment of olein with oxide of lead (litharge). When
boiled with this base, the olein is decomposed into oleic acid and oxide of glyceryl.
The former combines with the base, forming an insoluble soap, called oleate of oxide of
lead (diachylon plaster); and the oxide of glyceryl, separating in combination with water,
forms glycerin (hydrated oxide of glyceryl), a substance having a certain analogy with the
group of bodies termed alcohols. It remains dissolved in the water employed. If olein
is boiled with a solution of potash or soda, oleates of potash or soda are obtained; but being
soluble in water, they remain dissolved together with the glycerin.
The oleates of potash or soda, when separated from the water by processes immediately
to be discussed, are what we call, in common life, soaps. Similar soaps are formed by the
remainder of the fatty acids; for example, stearic and margaric acids. Palmitate of soda,
obtained by boiling palm oil with soda, likewise forms a chief ingredient of many soaps.
Potash and soda, as they occur in commerce, are combinations of the alkaline bases, thus
denominated by the chemists, with carbonic acid, and though by long boiling they could
decompose (saponify) fats, yet the operation is tedious, and the saponification generally
incomplete. It is better to deprive the alkalies of their carbonic acid, which is done by
mixing them with quicklime and water; the quick-lime combines with the carbonic acid,
forming an insoluble carbonate of lime (chalk), and the water retains the potash or soda
in solution, contaminated still with such impurities as the alkalies contained (sulphates