CARBURET OF SULPHUR. A lim pid volatile liquid of fetid smell and acrid taste. It boils at 112° F., and eva porates so rapidly as to congeal mercury in a vacuum. It is composed of two atoms of sulphur and one of carbon. It is used as a solvent for caoutchouc, CARBURETTED HYDROGEN. A generic name for the compounds of car bon and hydrogen, of which there are several, viz.: oil and coal gas, oil of lem ons, turpentine, naphtha, otto of roses, &c. CAR D._ MACHINES. Instru ments for arranging cotton and other fibres. After picking and disentangling, the cotton is in the form of a very clean, light, downy substance, consisting of short fibres thoroughly disentangled. But these fibres are not parallel: they lie across each other at every imaginable an gle, and any attempt to combine them to gether in this state would be fruitless ; they must be rendered parallel, and to effect this is the object of the beautiful operation of carding, one of those which have exercised such a large amount of in ventive ingenuity. If we were to take two combs, and pass the teeth of one be tween those of the other, we should have a rude idea of the process of carding, es pecially if we had a few fibres of cotton entangled among the teeth : for the move ment of the two combs world tend to ar range the fibres in some degree parallel. A number of pieces of wire are inserted in a piece of wood or leather, so that all shall project to an equal distance and at an equal angle ; and if two such pieces of apparatus were placed with their wires in contact, and moved in contrary direc tions, a few fibres of cotton placed on the lower one would be combed out by the up per one, and arranged parallel. In vari ous stages of the history of the manufac ture, the two cards have been arranged in different ways. Sometimes one was on a convex surface, and the other on a con cave surface fitted to it ; sometimes one was on a cylinder, and the other on a flat surface ; sometimes both were on the surfaces of cylinders. But the principle
of action is the same in all, and is nothing more or less than a process of combing. In some arrangements the cotton is brought into the form of a " lap," or flat layer, by the scutching-machine, and in that state transferred to the carding-en gine; while in other cases the latter is fed by hand with cotton.
These card-combs are sometimes set on cylinders, and applied to the burring and carding of cotton and wool.
In 1848, letters patent were granted for the mode of constructing the hollow cy linder, to which the teeth of burring or carding cylinders are to be attached. A light cylinder of tinned sheet metal is first it was first described as a solid by M. Thilourier.
At common temperatures and pres sures water absorbs its own volume of carbonic acid ; under a pressure of two atmospheres it dissolves twice its vol ume, and so on. Carbonic acid imparts briskness and a slightly pungent and sour taste to water thus impregnated with it: it also confers the effervescent quality upon many mineral springs. Car bonic acid is recognised by its rendering lime-water turbid. It extinguishes flame and suffocates animals ; hence the miners call it choke damp. Carbonic acid is con tained in marble, chalk, and all the va rieties of lime-stone; from which it is extracted by strong heat, as in the pro cess of burning lime ; or by the action of stronger acids, in which case the car bonic acid escapes with Mountains of lime-stone, therefore, are great natural repositories of carbonic acid. This gas is also produced during the respiration of animals, and is evolved in the process of fermentation.