Page:Cyclopaedia, Chambers - Supplement, Volume 1.djvu/612

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This is certainly pra&icable, though not ufually praaifed to the perfection that it might be : the principal thing to be endeavoured after, is the obtaining a taftelefs fpirit, capable of receiving any impreffion, and then the bufinefs of flavouring is eafy. The method of rectifying, by fixed alkaline falls, is capable of great improvement, as by Keeping the fpirit firft brought near to the ftate of alcohol, upon a well dried fait of tartar, or any other cheaper, but pure fixed alkali ; by this means it will be alnioft totally freed of its oil without volatilizing much of the fait, as it does in the way of diftillation ; by this means a weak tincture of fait of tartar may be procured, and an acid added to this, to takeoff the effects of the alkali in the fpirit, the whole is then to be diftilled ; and the fire being well managed, a very clean fpirit will be thus procured at one operation, fuch as can no W3y elfe be obtained at once. The ufe of the compound neutral falts in rectification feems not yet to be fufliciently known ; what is meant by thefe falts is a fixed alkaline fait faturated with an acid one. Such a fait has indeed been expected from the caput mortuum, or white faline cake, remaining upon the Dijlillatitm of the fpirit of nitre with oil of vitriol, but it proves too hard, ftony, and infoluble, to be of any great ufe on this occafion : a much better effect may be expected fromfoluble tartar, carefully pre- pared, and properly ufed ; though even this is apt to render the fpirit a little faponaceous. Some compound neutral falts have been made however upon this foundation, that would rectify common malt fpirit from proof at a fingle operation, much bet- ter than all the other more perplexed and tedious methods in ufe, A prudent ufe of fine dry fugar may alfo be of fome fervice, as it readily unites with the eflential oil, and detains and fixes it, without imparting any urinous or other naufeous flavour to the fpirit rectified upon it ; another hint to this purpofe, which may be made to turn to very good account, is that given by the ingenious method invented by Dr. Cox, of tak- ing all the oil out of the volatile falts, by firft bringing them to a neutral ftate with fpirit of fait, and then fubliming them with fait of tartar, which does the bufinefs to perfection. In the cafe of fpirits the acid may be varied, and virgin earth, chalk, calcined flints, or the like abforbents ufed in the ftead of fait of tartar, and yet the general effect will be the fame. Shaw's EflTay on Diftillery. Brewing for Distillation. Sec Brewing. Distilled juice of Tar. See TAR-water, Distilled waters. The waters dijiilled from plants and other medicinal things, may receive fomething from the veflels in which they are diftilled) which may in fome degree alter their properties. Even water alone diftilled in glafs veffels, and in thofe of metal, differs fo much, that thefe two diftillations be- ing mixed, will render one another turbid. The florentine academicians have taken this change of waters under their confideration among the many other minutiae, of natural and experimental philofophy omitted by others. They found that common water dijiilled in leaden veflels would render all other waters turbid, on mixing with it; whether it were fpring, fountain, river, or well water, except alone the wa- ter of the conduit at Pifa : an experiment that proved a qua- lity in that water, different from all others, though never be- fore fufpected in it. The experiment being repeated at various feafons afterwards, the water of this conduit was fometimes found to grow turbid alfo, but this was at fuch times as other waters, from rain, &c. had blended themfelves with the ge- nuine water of the fpring. Waters diftilled in glafs veffels, and mixed with waters diftilled \r\ lead veflels, were fuppofed by the Florentines indeed not to render one another turbid ; but, by the obfervations often made by the curious Redi, it proved that they did. This author affures us, that having dijiilled the parietaria in a glafs cucurbit, and fhifted the receiver fourteen times, and mixed all thefe fhifted waters with rofe water di- jiilled in lead, they always became turbid, though he repeated it after feveral months: but after diftilling in balneo, the re- mainder of thefe fourteen lhiftings, in a filver veffel, with a glafs head, changing the receiver eight times ; he found, in- deed, the water that was gathered in the eighth or laft re- ceiver untroubled : though he mixed with it feveral lhiftings of water diftilled in lead, but all the other feven lhiftings grew ftill turbid when thus mixed. Redi's Obfervat. Common water diftilled in gold, filver or glafs, with a glafs head, and kept in glafs, remains always clear; but, in cry f- tal of Pifa, it grows turbid in a few hours ; then milky, and in a few days yellow, and after all this bitter ; whereas in cryftal of Rome or Venice, the fame water does not grow turbid till after two or three days, and never becomes yellow or bitter in it j and in cryftal of Paris it will fcarce grow tur- bid, but after a very considerable time. The various materials ufed in the making thefe feveral kinds of cryftal, at the glafs- houfes of thefe different places, and the various manner of workingthem are the occafion of this great difference in them ; and on thefe principles we may find a new and more than or- dinary way of judging of the goodnefs of glaflea which feem equal to one another. Distilled waters of laurel leaves. See Laurocerasus. DISTILLERY. The bufinefs of fermentation is one of the

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great preparations to the Diftillery. What wc usually call virtautf fermentation in particular, is the kind it is concerned principally in. By this we ufually underftand that phyfical action oV inteftine commotion of the parts of a vegetable juice tinc- ture, or folution, which renders them fit to yield an inflamma- ble fpirit on diftillation.

This fermentation in the hands of the diftiller differs from the' common one, that is ufed in the making of potable vinous liquors, as being much more violent, tumultuary, active, and combinatory than that. A large quantity of ycaft, or other ferment, is added to the difliller's fermentation : the free air is admitted, and every thing is contrived to quicken the opera- tion, fo that it is fometimes finifhed in two or three days. This great difpatch, however neceffary to the large dealer, has its inconveniencies attending it j for the fpirit is by this means always fouler, more grofs, and really terreftrial, than it would have been if the liquor had undergone a proper fer- mentation in a flower manner. It alfo fuffers a diminu- tion in its quantity, from the violent and tumultuary admif- fion, conflict, and 3gitation of the free air, both in the body and upon the furface of the liquor, efpecially if the liquor be not immediately committed to the ftill as foon as the fermen- tation is fairly flacked or fully ended. It is a very difficult task to render the bufinefs of fermentation at once perfect and ad- vantageous. To ferment, in perfection, neceffarily requires length of time, and careful attendance, and clofe veflels, be- fide feveral other articles of nice management, which cannot be expected to be received and practifed in the lar^e way, on account of the trouble and expence, unlefs it could be proved to the diftillers, as poffibly it fome time may, that the quantity of fpirit would be fo much greater from the fame quantity of materials managed thus, than by the common way, that it will more than pay its own expence ; to which may be added, the very well known advantage of the fpirit thus procured by perfect fermentation, being much finer than that obtained in the common way: till this fhall be made out, it may not be amifs to try how much of the more perfect art of vinous fer- mentation, is profitably practicable by the diftiller in the pre- fent circumftances of things. The improvements to be made in this affair will principally regard, i. The preparation or previous difpofition of the fermentable liquor. 2. The addi- tions tending to the general, or fome particular end. 3. The admiffion or exclufion of the air. 4. The regulation of the external heat or cold ; and 5. A fuitable degree of reft at laft. When proper regard is had to thefe particulars, the liquor will have its due courfeof fermentation, and it will thence be- come fit to yield a pure and copious inflammable fpirit by diftillation. The tincture, folution, or liquor intended for fermentation, for the ftill, fhould be confiderably thin and aqueous. That fort of richnefs that there is in the ten fhil- ling fmall beer, is the utmoft that ought to be allowed to it. This property not only fits it to ferment readily, but alfo to yield a larger quantity in proportion of a pure vinous fpirit, than it would do if it were more rich and clammy : the grofs, foul, vifcid, and earthy particles of fuch glutinous liquors, be- ing after fermentation apt to rife up with the boiling heat which muft neceffarily be employed to raife the fpirit; and the fpirit thus of courfe comes over foul and fetid. There is alfo ano- ther advantage attending the thinnefs of this liquor, which is, that it will fooner become fine by ftanding before fermentation ; whence it may be commodioufly drawn off from its feces or bottom, which muft always in cafe of corn, malt, or any other mealy fubftance, be kept out where the purity of the fpirit is confulted. A certain degree of warmth feems necef- fary in all the northern climates, to all forts of artificial li- quors, intended for immediate fermentation, efpecially in winter ; but the natural juices of vegetables, which have never been infpiffated, as that of grapes, and other fruits, when fully ripened, will ufually ferment, as foon as they are ex- prelfed without any external afliftance. But, as a certain de- gree of infpiflation, prevents all tendency to fermentation in all vegetable juices, though otherwife ftrongly difpofed to fer- ment ; fo a long continuance, or an increafe of the infpiffat- ing heat, efpecially if it acts immediately through a metalline or folid body upon the juice, will deftroy its fermenting pro- perty ; and it will do this the more effectually, as the heat em- ployed approaches to that of fcorching, or the degree capable of giving an empyreuma. After the fame manner, feveral experiments make it appear that there is a certain degree of heat; the continuance, or leaft increafe of which, proves de- trimental or deftructive to fermentation ; as there is another, which in a wonderful manner encourages and promotes it. Thefe two degrees of heat ought to be carefully noted and. fettled by the thermometer, or other certain methods, for philofophtcal and chymical ufes; but for common, or alloeco- nomical occafions, they may be limited to what we call a tepid and fervid heat : a fervid heat is the bane of all vinous fermentation, as a tepid one, or rather an imperceptible warmth is the great promoter of them. In this neutral ftate therefore, with proper contrivances to preferve and continue it, the liquor is to be put into a fuitable veffel for fermentation; at which time if it works not of itfelf, it muft be quickened by

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