Lime juice may be advantageously employed in the manufacture of citric acid, the proportion of this acid being larger than in lemon juice.
CIV′ET. Syn. Civet′ta Zybeth′um, L. A perfume obtained from the civet cat (Viverra civella, Linn.), a fierce, carnivorous quadruped, somewhat resembling a fox, found in China and the East and West Indies. The civet is secreted in a sort of pouch between the anus and the sexual organs. “Several of these animals have been brought into Holland, and afford a considerable branch of commerce, especially at Amsterdam. The civet is squeezed out in summer every other day, in winter twice a week; the quantity procured at once is from 2 scruples to 1 drachm or more.”
Civet is frequently adulterated with spermaceti and butter, and a similar substance to civet, but of a darker colour, obtained from the polecat. When pure it has an odour intermediate between that of musk and ambergris, but less refined; a pale-yellow colour; an acrid taste; and the consistence of honey. It is used in perfumery.
CLAIRET. See Liqueur.
CLAR′ET RAGS. Syn. Tournesol en drapeau, Fr.; Bezet′ta cœru′lea, L. 1. Pieces of clean linen coloured with Auvergne—or ground archil.
2. Pieces of linen dipped into the juice of mulberries, blood-red grapes, lees of red wine, &c. Used to colour jellies, confectionery, the rind of cheeses, &c.
CLARIFICATION. The act of clearing or making bright; commonly applied to the process of ‘clearing’ or ‘fining’ the liquids by chemical means, instead of by filtration. The substances used for this purpose are popularly known as ‘clarifiers’ or ‘finings.’
The substances employed in the clarification of liquids operate by either mechanically embracing the feculous matter, and subsiding with it to the bottom of the vessel, or by inducing such a change in its nature or bulk that it subsides by its own density, in each case leaving the liquor transparent. Albumen, gelatin, the acids, certain salts, blood, lime, plaster of Paris, alum, heat, alcohol, &c., serve in many cases for this purpose. The first is used, under the form of white of egg, for the clarification of syrups, as it combines with the liquid when cold, but on the application of heat rapidly coagulates and rises to the surface, carrying the impurities with it, forming a scum which is easily removed with a skimmer. It is also much used for fining wines and liqueurs, particularly the red wines and more limpid cordials. Gelatin, under the form of isinglass, dissolved in water or weak vinegar, is used to fine white wines, beer, cider, and similar liquors that contain a sufficient quantity of either spirit or astringency (tannin), to induce its precipitation. Sulphuric acid is frequently added to weak liquors for a similar purpose, either alone or after the addition of white of egg or gelatin, both of which it rapidly throws down in an insoluble form. A pernicious practice exists among some unprincipled manufacturers of using certain salts of lead and potash to clear their liquors; especially those that are expected to sparkle in the glass, as ‘cordial gin,’ &c. For this purpose a little sugar of lead, dissolved in water, is first mixed up with the fluid, and afterwards a little more than half its weight of sulphate of potassa, also dissolved in water, is added, and the liquor is again ‘roused’ up. By standing, the sulphate of lead, formed by this mixture, subsides, and leaves the liquor clear. Bullock’s blood is used in the same way as isinglass or white of eggs, for fining red wines, beer, and porter. Lime, alum, alcohol, acids, and heat, act by curdling or coagulating the feculencies, and thus, by increasing
their density, induce their subsidence. Plaster of Paris acts, partly like the above, and partly like albumen, or gelatin, by developing and forcing down the suspended matter. Sand is often sifted over liquors (especially cordials and syrups), for the simple purpose of acting by its gravity, but appears to be quite useless, as it sinks too rapidly. The juices of plants are clarified by heat, which coagulates the albumen they contain. Marl or clay is frequently used to clear cider and perry. A strip of isinglass is generally employed to clarify coffee. See Wine, Brewing, Cordials, Coffee, Finings, Infusion, &c.
CLAY. Clay is formed from the disintegration of felspathic rocks, by the combined action of air and water. Its plasticity, when moist, and its capability of being made hard by heat, are properties which render it available for many useful purposes. The purest kind of clay is kaolin, or China clay, which consists almost entirely of silicate of aluminum. It is found in China; but a precisely similar substance is obtained from deposits in Cornwall and some parts of France. Pipe-clay, a white clay nearly free from iron, is found in large quantity in the island of Purbeck. Potter’s clay is found in many parts of Britain; that of Devonshire and Dorsetshire is much valued. Brick clay contains varying proportions of iron; hence the different colours of the bricks used in different countries. See Aluminum, Fuller’s earth, Ochre, &c.