Prep. (Barnard’s patent process.) A highly volatile fluid, discovered by Mr Barnard. India rubber or caoutchouc, as imported, cut into small lumps, containing about 2 cubic inches each, is thrown into a cast-iron still, connected with a well-cooled worm-tub (any flat vessel with a large evaporating surface will do, the entire top of which can be removed for the purpose of cleaning it out); and heat is applied in the usual way, until the thermometer ranges to about 600° Fahr., when nothing is left in the still but dirt and charcoal. The dark coloured fetid oil which has distilled over is next rectified along with 1⁄3rd its weight of water, once or oftener; and at each rectification becomes brighter and paler, until at about sp. gr. ·680 it is colourless, and slightly volatile. The product is then shaken up with nitro-hydrochloric acid, or chlorine, in the proportion of a 1⁄4 of a pint of the acid to 1 gallon of the liquid. To enable the dirt to be the more easily removed from the bottom of the still, common solder, to the depth of about 1⁄2 an inch, is thrown in.—Prod. 80%.
Prop., &c. Mixed with alcohol, caoutchoucin dissolves gums and resins, especially copal and india rubber, at the common temperature of the atmosphere, and it speedily evaporates, leaving them again in the solid state. It mixes with the oils in all proportions. It has been used in the manufacture of varnishes, and for liquefying oil paints, instead of turpentine. It is very volatile, and requires to be kept in close vessels. According to the researches of Himly, Gregory, and Bouchardat, the caoutchoucin of Barnard consists of several liquids, some of which have the composition of olefiant gas, and others that of oil of turpentine.
CA′′PERS. The flower buds of various species of Capparis, particularly C. spinosa, caper tree, preserved in vinegar. They are chiefly imported from Spain, Italy, and the south of France, where the caper tree is largely cultivated for the purpose. The flower-buds are picked daily, and thrown into a cask of strong pickling vinegar, until it becomes full, when it is sold to the dealers by the collector. The former sort them into different sizes by means of copper sieves, in a similar way to that adopted for lead shot and gunpowder. In this way they are divided into nonpareilles, capuchins, capotes, seconds, and thirds, of which the former, or smallest, are regarded as the best; but much depends upon the quality of the vinegar.
The bright green colour of capers, so much valued by the ignorant, arises chiefly from the presence of copper derived from the sieves used in sorting them. In many cases, copper coin, as sous and halfpence, are added for the purpose. Thus the eye is gratified at the sacrifice of the stomach, and an insidious poison introduced into the system, simply to give an unnatural appearance to a condiment which tastes better without it. See Copper.
CAPILLAIRE′. [Fr.] Simple syrup, or a concentrated solution of sugar in water, flavoured with orange-flower water, or some other similar aromatic. The name was originally given to a mucilaginous syrup, prepared by adding to an infusion of maiden-hair (Adiantum capillus Veneris) some sugar and orange-flower water.
CAP′NOMOR. See Kapnomor.
CAP′RIC ACID. HC10H19O2. Syn. Ru′tic acid; Acidum cap′ricum, L. An acid discovered by Chevreul, and obtained by decomposing caprate of barium with dilute sulphuric acid, or primarily by the saponification of butter or cocoa-nut oil, when it appears combined with butyric, caproic and caprylic acids. It is also procured by acting upon oleic acid or oil of rue with nitric acid.
Obs. When butter is saponified with caustic potassa or soda, and the resulting soap decomposed by adding an acid, in excess, and distilling the mixture, the four acids above named pass over into the receiver, in combination with water. The mixed acids may be separated by saturating them collectively with baryta, and by taking advantage of the unequal solubility of the newly formed barium salts. The less soluble portion (equal to about 1⁄20th of the dry mass) contains capric and caprylic acid; the larger and more soluble portion, butyric and caproic acid. On the same plan the two groups are resolved into their separate acids. These acids are deprived of their uncombined water by means of chloride of calcium. It is advisable to employ the term rutic acid, as the older term is easily confounded with caproic and caprylic.
Prop. Capric or rutic acid crystallises in fine needles, which fuse at 86° Fahr., giving out an odour resembling that of a goat. It is sparingly soluble in boiling water.
Prep. (Miller.) Castor oil is saponified by means of potassa or soda, and afterwards an excess of the hydrated alkali is added, amounting to one half the oil used. The mass is heated in a retort, and an oily liquid covered with water distils over. This oily liquid, which is the octylic alcohol, is rectified several times with potassa until the residue is no longer coloured brown.—Prop. A colourless liquid, of powerful aromatic odour; insoluble in water, but dissolving readily in acetic acid, ether, and alcohol. Its boiling point is 356° Fr., its sp. gr, ·823. The caprylate of ethyl, erroneously termed caprylic ether, is a colourless liquid, with an agreeable odour of pine-apples.