ALCOHOL. 



ALCOHOL. 



182 



the receiver. By repeated rectifications from large quantities of quick 

 lime, alcohol may be obtained perfectly absolute. Chloride of calcium 

 which has been fused so as to render it free from water, is an extremely 

 deliquescent salt, and is more powerful than most substances in sepa- 

 rating water from alcohol. Mix equal weights of spirit and pieces of 

 the fused chloride in a stopped bottle ; when the salt is dissolved, pour 

 off the clear solution into a distilling apparatus, and continue the opera- 

 tion until the product is equal to half the bulk of the spirit employed. 

 If the distillation be properly conducted, the alcohol obtained is perfectly 

 free from water. 



In iierforming any of these processes, however, it must be borne in 

 mind, that absolute alcohol absorbs water with great avidity, and eon- 

 -e<|uently it can neither be obtained nor preserved absolute, unless it be 

 carefully protected from the' air so as to prevent its absorbing atmos- 

 pheric moisture. 



Pure alcohol possesses the following properties : It is a limpid 

 rol< iiirless liquid, of an agreeable smell and a hot pungent taste. Its 

 specific gravity is 0'791 at 68% or 07947 at 59. It has never been 

 frozen, although exposed to a cold of 220. It is extremely volatile, 

 producing considerable cold during evaporation. Heat expands alcohol 

 in a greater degree than it does water; for 100,000 volumes become 

 104,108 by being heated from 32 to 100; whereas an equal bulk of 

 \v;it<T heated to the same degree, is increased only to 100,908. Under 

 the average atmospheric pressure alcohol boils at about 173, but in 

 the vacuum of the air-pump, ebullition occurs at 60, and even below it. 

 In becoming vapour, alcohol absorbs only 0'436 of the heat required to 

 evaporate an equal weight of water; and, according to Gay-Lussac, 

 (' Ann. de C'him. et de Phys.' xv.) the density of the vapour of anhydrous 

 (waterless) alcohol compared with that of atmospheric air, is as 1 '61 3 

 to I'OOO. When the vapour of alcohol is strongly heated, as by being 

 passed through a red hot porcelain tube, it is decomposed, and there 

 are obtained, gaseous hydrocarbons, aldehyde, naphthaline, benzole, 

 phenylic alcohol, and several other sxibstances, together with a small 

 amount of carbon. Alcohol, and the vapour arising from it, are 

 extremely inflammable ; it burns with a lambent flame. Although the 

 flame of alcohol yields but little light, its heat is intense ; it burns 

 without any smoke, .and the only products of the combustion, under 

 common circumstances, are water and carbonic acid. When, however, 

 alcohol is burned in the lamp without flame, in the wick of which a 

 platinum wire is kept ignited, then acetic acid and other products are also 

 formed. There are several substances which communicate colour to 

 the flame of alcohol : boracic acid and cupreous salts impart green ; 

 barytic salts, yellow ; and the salts of strontia, an intense and beautiful 

 crimson colour. 



Alcohol may be fired by the electric spark, which when passed 

 through a mixture of the vapour of alcohol and oxygen gas, causes it to 

 take fire and explode violently. The vapour of alcohol requires three 

 times its volume of oxygen gas to be perfectly burned, and it then 

 yield* water and twice its volume of carbonic acid gas. At low tempe- 

 ratures, alcohol suffers but little change by exposure to the air ; the 

 liortiou which does not evaporate is rendered weaker by attracting 

 water, and it absorbs at the same time some air. 



Alcohol has great affinity for, and readily mixes with water in all 

 proportions, and during their combination heat is evolved ; if, for 

 example, equal measures of water and of alcohol of specific gravity 

 0'825, both at 50, be suddenly mixed, the temperature is raised to 70 , 

 and the specific gravity of the mixture, when cooled, exceeds its calcu- 

 lated density ; if, however, the alcohol be weak, then the mean density 

 is diminished. 



For the density of various mixtures of alcohol and water, see 



Ar.COHOLOMF.TRY. 



In contact with acids, alcohol forms a vast number of ethereal salts, 

 several of which are remarkable for possessing the fragrant odour of 

 various fruits. With concentrated sulphuric acid it yields sulphovinic 

 acid, which, on being heated, produces ether. [ETHKR.J Oxidising 

 agents convert it into aldehyde .and acetic acid. Chromic acid acts 

 upon it so violently as to cause inflammation when strong alcohol is 

 dropped upon the acid. Pure alcohol does not oxidise when exposed 

 to the air, but when mixed with fermentisable matters it gradually 

 absorbs oxygen, and is converted into acetic acid. Chlorine acts 

 readily upon alcohol, forming a series, of chlorinated products, and 

 finally chloral. 

 The solvent power of alcohol is great ; and it has been long known 



stensively applied. Graham (' Trans. Royal Soc. Edin.') has 

 hown that, like water, it combines with bodies in definite propor- 



these compounds he terms alcoate ; not many of them have 

 been formed, and they were obtained simply by dissolving the salts 

 constituting their base, and previously rendered anhydrous, in absolute 

 alcohol, with the assistance of heat. On cooling, the alcoates were 



ted in the solid state ; the crystallisation was generally confused, 

 but in Dome cases regular forms appeared. The crystals are trans- 



' . soft, and easily fusible by heat in their alcohol of crystallisation ; 

 their formation is prevented by the presence of a small quantity of 

 water. ('hlorid of calcium forms an alcoate consisting of 2 atoms of 

 alcohol and 1 of the salt ; nitrate of magnesia, 1 atom salt + 3 atoms 

 alcohol ; alcoate of nitrate of lime consists of 2 atoms salt and 5 atoms 

 alcohol. Several metallic salts were also converted into alcoates, and 

 ui ; the alcohol of some alcoates is retained with so 



great force of affinity as not to be expelled at a temperature of 400 

 to 500. 



Alcohol is capable of dissolving the resins, and many similar bodies 

 upon which water has no action ; hence its use in varnish-making. 

 With the fixed oils, except castor oil, it does not readily unite ; but it 

 dissolves the essential oils and camphor with great facility, and hence its 

 use in pharmacy and perfumery. Some substances which are soluble 

 in water are precipitated from it by alcohol gum, for example ; while, 

 on the other hand, water precipitates resinous bodies from solution in 

 alcohol. Alcohol dissolves sulphur and phosphorus, but not the earths 

 or their carbonates : it also dissolves sugar, soap, the oxalic, tartaric, 

 gallic, benzoic, and some other acids. Alcohol is largely used in the 

 preparation of various kinds of ether. The results of its action with 

 sulphuric acid are very different according to circumstances : thus, by 

 varying the proportions, we may procure sulphovinic acid, ether, oil o'f 

 wine, or olefiant gas. As it remains 'fluid at the lowest temperatures, 

 it is advantageously employed in filling thermometer tubes, for experi- 

 ments on artificial cold ; its antiseptic properties are great, and hence 

 its use in preserving anatomical preparations ; on account of its ready 

 inflammability, the purity and the intense heat of its flame, it is con- 

 veniently, but not economically, employed in chemical lamps, usually 

 termed spirit lamps. 



It readily dissolves ammoniacal gas ; and as the caustic alkalies. 

 potash and soda, are taken up in large quantity by alcohol, and as it 

 does not dissolve their usual impurities, the solution, by dilution with 

 water and subsequent distillation, yields these alkalies in a state of 

 great purity. In analytical operations it is sometimes employed to 

 separate two salts, both of which are soluble in water, but only one iu 

 alcohol. It is also largely employed in proximate organic analysis, and 

 in the preparation of the various ethyl compounds used in chemical 

 investigations. 



For most of these purposes pure alcohol may be replaced by the 

 methylated spirit now allowed by the Excise under certain restrictions 

 to be sold free of duty. 



Alcohol, Medical propertien of. These are of a twofold kind; 

 first, those in which it is employed on account of its solvent powers, it 

 being, next to water, the most extensively employed solvent, to obtain, 

 preserve, or facilitate the .administration of a variety of active princi- 

 ples, vegetable, mineral, or animal ; .and secondly, those in which its 

 own powers over the human frame lead to its use as a therapeutic 

 agent. The former will be treated of under TINCTURES ; and it is 

 only necessary to observe here, that, besides for these, it is employed 

 in many pharmaceutical processes in which it does not ultimately 

 appear, either for its solvent or precipitating properties, such as in the 

 preparation of many of the alkaloids, namely, aconitiua, strychnia, &c., 

 j which, though the most potent medicinal agents we possess, are 

 greatly restricted in their application by the high price charged for 

 them. This arises partly from the minute quantity in which they 

 exist in their original sources, the plants which produce them ; but 

 far more from the high duty on alcohol, which places our practical 

 ! chemists at a great disadvantage compared with those of France and 

 ! Germany. Methylated spirit is now allowed to be used, which is a 

 great boon. 



The therapeutic properties of alcohol are therefore the only pro- 

 perties to be noticed here ; and it is by no means intended to discuss 

 points which have excited keen controversies in reference to the 

 employment of alcoholic stimulants as ordinary beverages, but simply 

 that employment of them which is conceded to be allowable by all 

 parties their use as medicinal agents. Besides, as many who do not 

 require them are, in accordance with the usages of society, in the 

 habit of taking them, it is proper to indicate which are the least 

 hurtful. The excessive use of ardent spirits is deservedly reprobated, 

 and every reasoning person will gladly lend his aid to root out this 

 .almost national vice ; the evil effects of which are not limited to the 

 individual, as the physical ailments engendered by habitual drinking 

 have a great tendency to become hereditary. The mental powers of 

 the offspring are also greatly influenced by the habits of the parent ; 

 and diseases of the brain, with derangement of the intellectual faculties, 

 are the consequence. The extension of education and the better tone 

 of feeling in the higher classes have done something to banish inebriety 

 from the upper circles of society ; and a more correct understanding of 

 what is for their true interests has abated it among the labouring 

 classes. Furnishing the operatives with the means of rational anil 

 healthful recreation, both mental and bodily, after the hours of 

 toil, will aid this fortunate revolution. The refreshment of a bath 

 will be found greater, more lasting, and more economical for the 

 workman, than any artificial stimulant, and has been advocated by 

 themselves. 



It is proper however that the mode of action of alcohol should be 

 understood, to determine when it should be used. A single moderate 

 dose, suitable for the individual, produces effects which are entirely 

 limited to the viscera of the abdomen. They extend themselves from 

 the solar plexus of nerves to the organs upon which the splanchnic 

 nerve is distributed, and excite in these a livelier action. A feeling of 

 comfort in the abdomen, quicker and more powerful digestion, 

 stronger peristaltic motions, increased desire for meat and drink, more 

 abundant secretion, especially augmented secretion from the kidneys, 

 are the common phenomena which result from the lowest degree of its 



