3. From ferrocyanide of potassium in fine powder, and 8 or 10 times its weight of concentrated sulphuric acid, heated together in a glass retort.
Obs. All the processes except the last give a mixture of carbonic acid and oxide. It is therefore necessary to pass the gas through a caustic alkaline solution or milk of lime to deprive it of carbonic acid. It may then be passed over dried chloride of calcium, to deprive it of moisture. It may be collected either over mercury or water, as the latter absorbs very little of this gas.
Prop. Carbonic oxide is colourless, inodorous, neutral, inflammable, and irrespirable. It is extremely poisonous, 1% mixed with air being sufficient to cause dangerous drowsiness. The deaths produced by the combustion of charcoal in close rooms are now attributed to this gas. The antidotes, &c., are the same as for poisoning from inhaling carbonic acid.
CAR′BUNCLE. A larger sized and dangerous form of boil, attended by extensive sloughing. The treatment consists in lancing, poulticing, and the adoption of a generous diet, with wine and stimulants. The safer plan, however, is to seek the advice of a medical man.
CAR′BURETTED HY′DROGEN. See Hydrogen.
CARD′AMOM. Syn. Card′amum; Cardamo′mum, B. P. The seed or fruit of the Elettaria Cardamomum forms the officinal cardamom. It is warm, pungent, carminative, and stomachic, and is largely used as a condiment in the East, and in Europe as an adjuvant in other medicines. Several kinds of cardamoms used medicinally and as spices are produced by the genus Amomum, belonging to the natural order Zingiberaceæ, the Ginger family.
CARD′BOARD. Cardboard, or sized pasteboard, is made of two to fifteen sheets of sized paper, pressed and stained. There are varieties of cardboard known as Bristol-board, London-board, the former being largely used for water-colour drawings, mounting-board, ornamental board, &c.
CAR′MINATIVES. Medicines that allay flatulency and spasmodic pains. Among the principal carminatives are ANISEED, CARAWAY SEED, CARDAMOMS, CASSIA, CINNAMON, GINGER, PEPPERMINT, and the PEPPERS. To these may be added ARDENT SPIRITS, and most of the AROMATIC ESSENCES and TINCTURES. See Mixtures, Patent Medicines, &c.
CAR′MINE. Syn. Carmine red, Vegetable scarlet; Carmi′num, L. A beautiful red pigment prepared from the cochineal insect.
Prep. The preparation of carmine is little understood, but success in its manufacture depends less on any mystery connected with the process than on the employment of the purest water and the best materials, and the exercise of moderate care, dexterity, and patience. The following forms will produce carmine of the richest hues down to ordinary and common, according to the skill possessed by the manipulator.