Page:The American Cyclopædia (1879) Volume VI.djvu/153

 DISTILLATION DISTRESS 145 one fifth of the distilled liquors consists of whiskey and rum, distilled to about proof, and so left to ripen with age. Considerable whiskey is made from rectified spirits of about 75 per cent, alcohol, which is reduced and flavored by the addition of raw whiskey not rectified. All distilled liquors are sold by the gallon, according to the proof. Proof spirit is reckoned by the government as 100, which is 50 per cent, absolute alcohol. DESTRUCTIVE DISTILLATION. When organic bodies are excluded from the air and subjected to heat, they undergo decomposition, and the constituent atoms or molecules rearrange them- selves into new compounds. The causes of this are various, and depend much upon the conditions which are present. The elective affinities of atoms and molecules, when a va- riety of substances are mingled together, vary with the heat and with the nature of the sub- stances with which they are surrounded. Two or more elements united in a compound, re- quiring a certain degree of heat to separate them, will require less when another compound is present, the amount depending upon the affinity which a constituent of one compound may have for a constituent in the other. Or- ganic bodies, which are usually composed of several compound constituents (as woody fibre, starch, resin, oils, and water), very readily suffer a complete change in their chemical as well as their organic structure by the simple application of heat, and without the presence of a supporter of combustion. When wood is enclosed in an iron tube and subjected to heat, various new bodies are formed of an inorganic character, and of a composition and number depending upon the duration and degree of heat. Decomposition commences at about 284 F. ; and between this and red heat various gases, vapors, liquids, and solids are produced. The products of the lowest temperature con- tain the most oxygen, as water and carbonic and acetic acids. As the temperature rises bodies containing less oxygen are formed, such as wood spirit, acetone, and creosote. At a still higher temperature, hydrocarbons, such as toluene, xylene, eupione, and paraffine, ap- pear ; and as the temperature approaches red- ness, hydrogen is abundantly formed. By con- necting the retort with condensing vessels, by means of good-sized exit tubes, the various volatile products may be collected, and subse- quently separated by fractional distillation and otherwise. The manufacture of illuminating gas illustrates the destructive distillation of bituminous coal on a large scale. The pro- ducts may be divided into three classes, viz. : 1, coke, consisting of carbon, sulphuret of iron, and ash ; 2, ammoniacal liquor, containing car- bonate, sulphide, chloride, cyanide, and sulpho- cyanide of ammonium ; 3, tar, embracing a great variety of solid and fluid hydrocarbons and acids, among which are benzole, toluole, xylole, naphthaline, anthracene, and carbolic or l)henic, oxyphenic, and cresylic acids, together with creosote, a compound of homologous oxy- phenic and methylic acids ; also several bases, as aniline, iridoline, and rubidine ; 4, illuminating gas, containing light-yielding compounds, such as acetylene, C 2 H 2 ; ethylene, or olefiant gas, CaH 4 ; benzole, C 6 H 6 ; naphthaline, CioH 8 ; pro- pyle, CsH? ; butyle, C4H 7 ; mingled with hydro- gen, carbonic oxide, and impurities, such as car- bonic acid, ammonia, cyanogen, sulpho- cyano- gen, and sulphuretted hydrogen. These pro- cesses involve highly complex reactions, the many stages of which are yet imperfectly un- derstood. The destructive distillation of acids and the simpler bases are more easily under- stood, the products being often readily traced to their origin. The decomposition of the acids takes place differently according as they are separate or in the presence of bases. When distilled alone many undergo a simple elimina- tion of carbonic acid, with the formation of a pyro-acid. Thus, gallic acid, when heated in a close vessel to 419 F., is decomposed into pyrogallic and carbonic acids, as follows: C 7 H a 6 = C 6 H 6 3 + CO 2 Gallic acid. Pyrogallic acid. Carbonic acid. Other reactions are not quite as simple. Thus, oxalic acid yields water, carbonic acid, carbonic oxide, and formic acid, as follows : 2C 2 H 2 4 = H 2 + CO + 2C0 2 + CH 2 O 2 Oxalic acid. Water. Carb. ox. Carb. acid. Formic acid. As an example of the destructive distillation of a salt, may be taken that of acetate of lime, which is converted into acetone and carbonate of lime, thus: 2C 2 H 3 CaO 2 = Ca a C0 3 + C 3 H 6 O Acetate of lime. Carb. lime. Acetone. FRACTIONAL DISTILLATION is the separating of different constituents which naturally exist or have been artificially produced in a mass. This is accomplished quite readily on account of the different temperatures at which the va- rious constituents pass into vapors. The re- fining of petroleum is an example of fractional distillation. (See PETROLEUM.) DISTRESS (Lat. distringere, to press, straight- en, wring out), a term applied to the taking of property of a tenant for non-payment of rent ; to the seizing of cattle for damage done by them ; to a levy upon property to enforce the payment of taxes ; and lastly to a proceeding to compel the appearance of a party who can- not be found. In the two cases first men- tioned, the landlord or person who had been injured could make the seizure himself or by his deputy ; an anomalous authority, entirely at variance with a fundamental principle of law that parties should not be permitted to redress their own injuries without judicial process. The recaption of property which has been wrongfully taken away, or wrongfully detained, or the reentry upon lands of which a man has been dispossessed, though analogous in one respect to distress for rent or damage