There is a remarkable relation between the specific gravity of a body in the gaseous state and its chemical equivalent or combining proportion—a relation of such a kind that quantities by weight of the various gases, expressed by their equivalents, or, in other words, quantities by weight which combine occupy, under similar circumstances of pressure and temperature, either equal volumes or volumes bearing a simple proportion to each other. This relation accounts for the law of COMBINATION BY VOLUME discovered by Gay-Lussac, and thus expressed:—
When gases combine, chemical union invariably takes place, either between equal volumes or between volumes which bear a simple relation to each other.
Gerhardt assumes that equal volumes of the elementary gases and vapours, when compared under similar conditions of pressure and temperature, contain the same number of atoms. Consult the chemical works of Fownes, Roscoe, Watts, &c. See Affinity, Atomic Theory, Equivalents, &c.
COMPOUND CHINESE TABLET OF ALABASTER (John Irvine). A cosmetic powder for the skin. It consists of chalk, free from injurious metals. (Chandler).
Compound Chinese Tablet of Alabaster (Shand). Identical in use and composition with the last-mentioned powder.
COMPOUND SUGAR-COATED MAY-APPLE PILLS (Dr Scott). Recommended as “antibilious, cathartic, chemical family pills.” Sugar-coated pills, consisting of bitter extract, powdered podophyllum root, rhubarb, jalap, and pepper. (Hager).
COMPRESSES DESINFECTANTES DE LE PERDRIEL. Charcoal powder incorporated with paper.
CONCENTRATED CASTOR OIL in Capsules of Gelatin (Taylor). 24 gelatin capsules filled with castor oil, containing ·5 per cent. of croton oil. (Hager).
CONCENTRA′TION. The volatilisation of part of a liquid in order to increase the strength of the remainder. The operation can only be performed on solutions of substances of greater fixity than the menstrua in which they are dissolved. Many of the liquid acids, solutions of the alkalies, &c., are concentrated by distilling off their water.
In pharmacy, the term CONCENTRATED is commonly applied to any liquid preparation possessing more than the usual strength. Thus, we have concentrated infusions, decoctions, liquors, solutions, tinctures, and essences, most of which are made of 8 times the common strength. This is generally effected by using 8 times the usual quantity of the ingredients, with a given portion of the menstruum, and operating by digestion and percolation; the latter being generally adopted when the articles are bulky. When the menstruum is water, a little spirit is added, to make the product keep. See Decoction, Infusion, &c.