Carbonic acid gas is destitute of colour, has a sourish, suffocating smell, an acidulous pungent taste, imparts to moist, but not dry, litmus paper, a transient reddish tint, and weighs per 100 cubic inches, 461⁄2 grains; and per cubic foot, 8031⁄2 grains; a little more than 33⁄4 oz. avoirdupoid. A cubic foot of air weighs about two thirds of that quantity, or 527 grains. It may be condensed into the liquid state by a pressure of 40 atmospheres, and this liquid may be then solidified by its own sudden spontaneous evaporation. If air contain more than 15 per cent. in bulk of this gas, it becomes unfit for respiration and combustion, animal life and candles being speedily extinguished by it.
Before a person ventures into a deep well, or vault containing fermenting materials, he should introduce a lighted candle into the space, and observe how it burns. Carbonic acid, being so much denser than common air, may be drawn out of cellars or fermenting tubs, by a pump furnished with a leather hose, which reaches to the bottom. Quicklime, mixed with water, may be used also to purify the air of a sunk apartment by its affinity for, or power of, absorbing this aërial acid. See [Mineral Waters] and [Soda Water].
CARBONIC OXIDE. See the article [Carbon].
CARBUNCLE. A gem highly prized by the ancients; most probably a variety of the noble garnet of modern mineralogists.
CARBURET OF SULPHUR, called also sulphuret of carbon, and alcohol of sulphur, is a limpid volatile liquid, possessing a penetrating fetid smell, and an acrid burning taste. Its specific gravity is 1·265; and its boiling point is about 112° Fahr. It evaporates so readily, and absorbs so much heat in the vaporous state, that if a tube containing quicksilver, surrounded with lint dipped in this liquid, be suspended in the receiver of an air-pump, on making the vacuum, the quicksilver will be congealed. It consists of 15·8 carbon and 84·2 sulphur, in 100 parts; being two equivalent primes of the latter to one of the former.
CARBURETTED HYDROGEN. A compound of carbon and hydrogen, of which there are several species—such as oil-gas, coal-gas, olefiant gas, oil of lemons, otto of roses, oil of turpentine, petroleum, naphta, naphthaline, oil of wine, caoutchoucine and caoutchouc.
CARDS, PLAYING. (Cartes à jouer, Fr.; Karten, Germ.) Mr. de la Rue obtained, in February, 1832, a patent for certain improvements in the manufacture of playing cards, which he distributed under three heads: first, printing the pips, and also the picture or court-cards, in oil colours by means of types or blocks; secondly, effecting the same in oil colours by means of lithography; and thirdly, gilding or silvering borders, and other parts of the characters, by the printing process, either by types, blocks, or lithography.
In the ordinary mode of manufacturing playing cards, their devices are partly produced by copperplate printing, and they are filled up with water colours by the means called stencilling.
The patentee does not propose any material alteration in the devices or forms upon the cards, but only to produce them with oil colours; and, to effect this, he follows precisely the same mode as that practised by calico printers.