ALCOHOL is a limpid, colorless liquid, of a hot, pungent taste, and having a slight but agreeable smell. It is the characteristic ingredient of fermented drinks, and gives them their intoxicating quality. Looking at the extraordinary consumption of these liquors, and to the extensive application of A. for other purposes, it becomes one of the most important substances produced by art.
There is only one source of A.—namely, the fermentation of sugar or other saccharine matter. Sugar is the produce of the vegetable world. Some plants contain free sugar, and still more contain starch, which can be converted into sugar. The best vegetable substances, then, for yielding A. are those that contain the greatest abundance of sugar or of starch. See DIASTASE, FERMENTATION, and DISTILLATION.
Owing to the attraction of A. for water, it is impossible to procure pure A. by distil lation alone. Common spirits, such as brandy, whisky, etc., contain 50 or 52 per cent of A. ; in other words, they are about half A., half water. Proof-spirit, which is the standard by means of which all mixtures of A. and water are judged, contains 57.27 per cent by volume, and 49.50 per cent by weight, of A. The specific gravity of proof spirit is 918.6; and when a spirit is called above proof, it denotes that it coutains an excess of A.; thus, spirit of vine, or rectified spirit, with specific gravity 838, is 54 to 58 over proof, and requires 54 to 58 per cent of water to be added to it, to bring the strength down to that of proof-spirit; whilst the term under proof has reference to a less strong spirit than the standard. See AREOMETER. The most primitive method of learning the strength of A. was to drench gunpowder with it, set fire to the spirit, and if it inflamed the gunpowder as it died out, then the A. stood the test or proof, and was called proof spirit. The highest concentration possible by distillation gives 90 par cent of A., still leav ing 10 per cent of water. In order to remove this, fused chloride of calcium, quicklime, or fused' carbonate of potash, is added to the alcoholic liquid, the whole allowed to stand for twelve hours, and then the spirit may be distilled off quite free from water. Spirit of wine may also be deprived of its remaining water by suspending it iu a bladder in a warm place; the bladder allows much of the water to pass through and evaporate, but little of the A. The latter method is called Soemmering's process, and depends on the different degrees of rapidity with which the bladder admits of water and A. passing through it. Thus, introduce into one bladder 8 oz. of water, and into a second, 8 oz. of A., and allow both bladders to be similarly exposed on a sand-bath, till all the water has evaporated through the pore of the membrane, which will be accomplished in about 4 days, and it will then be observed that whilst 8 oz. water have made their exit from the
bladder, that only one ounce of A. has thus evaporated, and 7 oz. still remain in the bladder. This experiment explains why smugglers, a few generations ago, could supply a whisky which was stronger, and hence esteemed preferable, as they carried the whisky in bladders around their persons, and the water escaping therefrom in much greater pro portion than the A., a stronger spirit was left.
A. is used medicinally, both internally and externally. The more common form for internal use is brandy, and is that generally recommended by physicians. As a stomachic stimulant, A. is used in sea-sickness and indigestion. As a stimulant andrestoratire, it is employed with advantage in the later stages of fever. It is also employed internally as a powerful excitant to prevent fainting during operations, and to assist in restoration in cases of suspended animation. In cases of diarrhea, unaccompanied by inflammation, it is often of great benefit. Externally, A. is applied to stop hemorrhage, to harden the cuticle over tender parts. as the nipples of females for some time before delivery, and to feet which have been blistered from long walking or tight-fitting shoes.
Absolute or anhydrous A. has a specific gravity of 793 at the temperature of 60'. It boils at 173°, and has not been frozen by any cold hitherto produced. Reduced to a temperature of —130°, A. becomes of an oily and greasy consistence; at —146' it assumes the aspect of melted wax; and at —166° it gets still thicker, but does not congeal at the lowest attainable temperature. This property of non-freezing at any degree of cold to which the earth is subjected, has led to the employmentof A. colored red by cochineal, in the thermometers sent out to the arctic regions. It acts as a poison by abstracting the water from the parts it touches. It is highly inflammable; its combustion yielding only carbonic acid and water. When mixed with water, heat is evolved, and a condensation takes place. The formula of A. is In 100 lbs., therefore, of A., about 53 are carbon, 13 hydrogen, and 34 oxygen. Besides the A. consumed in wine, beer, and spirits, it is much employed in pharmacy and in the arts. It is a powerful solvent for resins and oils: and hence is employed in the preparation of varnishes. In Germany, a cheap spirit made from potatoes is much used for cooking on a small scale. See 3IErnv LATE') SPIRIT; and ALCOHOL and ALCOHOLS. The use and abuse of alcoholic drinks will be considered under FOOD AND DRINK, and TEMPERANCE.