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VIL'LOUS, adj. Lat. villosus. Shaggy; rough; cennes, a favorite resort of the Parisians. Populafurry.

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VINCA, in botany, a genus of the monogynia order, and pentandria class of plants; natural order thirtieth, contortæ : COR. twisted; there are two erect follicles: SEEDS naked. There are five species; only two of which are natives of Britain. 1. V. major, great periwinkle. It has a woody, erect stem; leaves broader and sharper pointed; pedicles of the flowers straight, and calyx as long as the tube; otherwise like the next. 2. V. minor, small periwinkle, has a woody, creeping, slender, crooked stem; leaves long, oval, entire, pointed, opposite, glossy. Flowers single, on long curved pedicles from the ale of the leaves, which are large and blue.

VINCE (Rev. Samuel), A. M., F. R. S., late Plumian professor of astronomy and experimental philosophy at Cambridge, was of humble Suffolk parentage; but the munificence of Mr. Tilney, of Harleston, enabling him to enter himself of Caius College in 1775, he distinguished himself by gaining one of Smith's mathematical prizes, and became the senior wrangler of his year. In 1796, then a fellow of Sidney Sussex College, he was elected to the professorship, which he afterwards filled in so distinguished a manner, and which he held till his death in 1821. His works are a treatise on the Elements of Conic Sections, 8vo. 1781; another on Practical Astronomy, 4to., 1790; Plan of a Course of Lectures on Natural Philosophy, 8vo., 1793; The Principles of Fluxions, 2 vols., 8vo., 1795; The Principles of Hydrostatics, 8vo., 1796, 1800; A Complete System of Astronomy, 2 vols., 4to., 1797-1799: 3 vols., 4to., with additions, 1814; A Vindication of Christianity against the objections of Hume, in two discourses, preached before the University, 1798–1809; A Treatise on Trigonometry, the nature and use of Logarithms, &c., 8vo., 1800; A Confutation of Atheism, from the Laws of the Heavenly Bodies, 8vo., 1806; and On the Hypotheses accounting for Gravitation from Mechanical Principles, 8vo., 1806. He was, at the time of his decease, rector of Kirkby Bedon, vicar of South Creak (both in Norfolk), and archdeacon of Bedford.

VINCENNES, a town and castle of France, near the confluence of the Seine and Marne, about three miles east of Paris. The castle was built in a remote age, as a country residence of the royal family. It continued a palace during three centuries; but, since Louis XIV. removed the court of Versailles, has been used as a state prison. It is surrounded by a deep ditch, and has nine towers, of great height and solidity. The largest, called the dungeon, is surrounded by a separate ditch of forty feet in depth. It was here that the unfortunate duke d'Enghien was murdered on 21st March 1804. Adjoining to the castle is a fine park, and a forest called the Bois de Vin

tion 1800.

VINCENNES, a post town of the United States, and capital of Knox county, Indiana, on the east bank of the Wabash, 100 miles from its junction with the Ohio, in a direct line, and nearly 200 miles by the course of the river.

VINCENT (Thomas), a divine who continued to preach regularly during the plague. He died in 1671. He wrote God's Terrible Voice in the City by Plague and Fire, an Explanation of the Catechism, and other religious books.

VINCENT (Nathaniel), a non-conformist, wrote the Conversion of a Sinner, and the Day of Grace, 8vo.; several sermons and other pious books. He died in 1697.

VINCENT (William), D. D., master of Westminster School, was born in London in 1739. He was educated at Westminster, and Trinity College, Cambridge, where he obtained a fellowship. In 1762 he became an usher, and nine years after succeeded to the office of second master, at Westminster. He now took the degree of D. D., and was appointed chaplain in ordinary to the king. In 1778 he became vicar of Longdon, in Worcestershire; but soon after resigned his benefice for the rectory of Allhallows, Thames Street, in London. In 1788 he became head master at Westminster, where he continued to preside till 1801, when he was made a prebend; and two years after he succeeded to the deanery of Westminster, on the promotion of Dr. Horsley to the see of St. Asaph. As an author dean Vincent is principally known on account of his commentary on Arrian's Voyage of Nearchus; and his Periplus of the Erythrean Sea, republished together under the title of The Commerce and Navigation of the Ancients in the Indian Ocean, 1807, 2 vols., 4to. The Voyage of Nearchus was translated into French by Billecocq, Paris, 1800. Dr. Vincent died in December 1815. He published also The Conjugation of the Greek Verb, and the Greek Verb Analysed; A Defence of Public Education; and a Charity Sermon. A volume of his Discourses, with his life, was published posthumously.

VINCENT (St.), an island of the West Indies, is twenty-three miles long, and eighteen broad, containing 84,000 acres, of which nearly one half consist of mountains incapable of improvement. The island is sufficiently watered by twenty small rivers, turning sugar mills. It is divided into five parishes, with one town, named Kingston, on the south-west, and three insignificant villages. The population in 1787 was 1450 whites and 11,853 negroes. In the same year the exports of the island sold for £186,450 in England. They were composed of coffee 634 cwt., cotton 761,880 lbs., sugar 65,000 cwt., rum 88,000 galls., and cocoa 143 cwt. The peace establishinent of the island is a regiment of regular infantry, and a company of artillery, besides a Negro eorps, raised in the island, and a militia of two regiments, serving without pay. The governor's salary is £2000.

VINCENT, CAPE ST., the south-west point of Portugal, noted for the naval victory gained off it on 14th February 1797, by Sir John Jervis. Long. 8° 58′ 39′′ W., lat. 37° 2′ 54′′ N.

VINCENT (St.), BAY, a bay on the north coast of Terra del Fuego, a little to the east of cape St. Vincent.

VINCENTIUS, one of the Christian Fathers,

A. D. 434. His works are best edited by Balu-
zius, Paris, 1699.
VINCI (Leonard), Da, was born in the castle of
Vinci near Florence in 1445. Verochio was his
master, whom he soon excelled, as he did all the
painters of his time. At Milan he founded his ce-
lebrated school of painting. He was also an excel-
lent architect, and constructed the famous aqueduct
which supplies Milan with water. From that place
he went to Florence, where he labored with Michael
Angelo, in ornamenting the grand council chamber.
At the invitation of Francis I. he visited the French
court, where he died in the arms of that monarch,
in 1520. He composed a great number of discourses
on curious subjects; but none of them have been
published but his Treatise on the Art of Painting.
VINCIBLE, adj. Lat. vinco. Conquerable;
superable.

He, not vincible in spirit, and well assured that shortness of provision would in a short time draw the seditious to shorter limits, drew his sword. Hayward.

VINCULUM, in algebra, a character in form of a line, or stroke drawn over a factor, divisor, or dividend, when compounded of several letters or quantities, to connect them, and shows that they are to be multiplied or divided, &c., together by the other term. Thus d x a + b. -c shows that dis to be multiplied into a + b--c. VINDALIUS, a writer in the age of Augustus, who wrote ten books on agriculture.

VINDELICI, an ancient people of Germany, between the head of the Rhine and the Danube; Vindelicia, their country, forms now part of Suabia, and Bavaria, and Augsburg was their chief town, Augusta Vindelicorum. VINDE MIATE, v. n. gather the vintage.

Lat. vindemia. .To

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Public revenges are for the most part fortunate; but in private revenges it is not so. Vindicative persons live the life of witches, who, as they are mischievous, so end they unfortunate.

Bacon.

The afflictions of Job were no vindicatory punishments to take vengeance of his sins, but probatory chastisements to make trial of his graces.

Bramhall.

The fruits of adusted choler, and the evaporations of a vidicative spirit.

I may assert eternal providence,

And vindicate the ways of God to man.

Howel.

Milton.

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VINE, n, s.
VINEYARD,
VI'NOUS, adj.
VINTAGE, n.s.
VINTNER.

Lat. vinea. The plant that bears the grape: the field or ground where vines grow: vinous is consisting, or having the annual produce of vines, or the season for gathering qualities, of wine: vintage, the

it: vintner, a seller of wine.

The captain left of the poor to be vine-dressers.
2 Kings.
The vine-prop elm, the poplar never dry. Spenser.
Let us not live in France; let us quit all,

And give our vineyards to a barbarous people. Shaksp.
The vintner may draw what religion he pleases.

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the hot sun; and therefore vinegar will not burn, much Vinegar is made by setting the vessels of wine against of the finer parts being exhaled.

Bacon.

Heaven's blest beam turns vinegar more sour. Pope. VINEGAR, acetum, an agreeable acid and penetrating liquor, prepared from wine, cyder, beer, medicine and a sauce. The word is French, vinaiand other liquors; of considerable use, both as a gre; formed from vin, 'wine;' and aigre, 'sour'. See ACETUM, and CHEMISTRY. Wine and other vinous liquors are changed into vinegar by the acetous fermentation, which is nothing more than the acidification or oxygenation of wine, produced in

the

open air by means of the absorption of oxygen. Vinegar is composed of hydrogen and carbon united together in proportions not yet ascertained, and changed into the acid state by oxygen. As vinegar is an acid, we might conclude from analogy that it contains oxygen; but this is put beyond doubt by direct experiments. In the first place, we cannot

The more numerous the offenders are, the more his change wine into vinegar without the contact of air

containing oxygen; secondly, this process is accompanied by a diminution of the air in which it is carried on from the absorption of its oxygen; and, thirdly, wine may be changed into vinegar by any other means of oxydation. Independent of the proofs which these facts furnish of the acetous acid being produced by the oxygenation of wine, an exDistinguish betwixt a passion purely vindicative, and periment made by Chaptal gives a distinct view of

justice is concerned to vindicate the affront. Tillotson. Suits are not reparative, but vindictive, when they are commenced against insolvent persons. Kettlewell. Augustus was of a nature too vindictive to have contented himself with so small a revenge.

Assemble ours, and all the Theban race,

To vindicate on Athens thy disgrace.

Dryden.

Id.

what takes place in the process. He impregnated some water with about its own bulk of carbonic acid gas, procured from beer vats in fermentation; and placed this water in a cellar, in vessels communicating with the air, and in a short time the whole was converted into acetous acid. This car bonic acid gas, procured from beer vats in fermentation, is not perfectly pure, but contains a great quantity of alcohol in solution; wherefore water impregnated with it contains all the materials necessary for forming the acetous acid. The alcohol furnishes hydrogen and one portion of carbon; the carbonic furnishes oxygen, and the rest of the carbon; and the air of the atmosphere furnishes the rest of the oxygen necessary for changing the mixture into acetous acid. From this observation it follows that nothing but hydrogen is wanting to convert carbonic acid into acetous acid; or, more generally, that by means of hydrogen, and according to the degree of oxydation, carbonic acid may be changed into all the vegetable acids: and, on the contrary, that, by depriving any of the vegetable acids of their hydrogen, they may be converted into carbonic acid.

A process still frequently used in making vinegar consists in fixing two casks in a warm room or place, to which two false bottoms of basket-work are fixed at a certain distance, upon which the refuse of grapes and vine twigs are placed. One of these tuns is filled with wine, and the other only half filled. The fermentation begins in this last; and, when it is in full action, it is checked by filling the cask up with wine out of the other. The fermentation then takes place in the last mentioned cask, that remained half filled; and this is checked in the same manner by pouring back the same quantity of liquid out of the other and in this way the process is continued till the vinegar is made, which is usually in about fifteen days. When the fermentation developes itself, the liquid becomes heated and turbid; a great number of filaments are seen in it; it emits a lively smell; and much air is absorbed, according to the observation of the abbé Rozier. A large quantity of lees is formed, which subsides when the vinegar becomes clear. This lees is very analogous to the fibrous matter. Vinegar is purified by distillation. The first portions which pass over are weak; but soon afterwards the acetous acid rises, and is stronger the later it comes over in the distillation. This fluid is called distilled vinegar; and is thus cleared of its coloring principle, and the lees, which are always more or less abundant. Vinegar may likewise be concentrated by exposing it to the frost. The superabundant water freezes, and leaves the acid more condensed.

Take however a middling sort of beer, indifferently well hopped; into which, when it has worked well and grown fine, put some rape, or husks of grapes, usually brought home for that purpose; mash them together in a tub: then, letting the rape settle, draw off the liquid part, put it into a cask, and set it in the sun as hot as may be; the bung being only covered with a tile, or slate-stone: and in about thirty or forty days it will become a good vinegar, and may pass in use as well as that made of wine if it be refined, and kept from turning musty. Or thus:-To every gallon of spring-water add three pounds of Malaga raisins; which put into an earthen jar, and place them where they may have the hottest sun from May till Michaelmas; then pressing all well tun the liquor up in a very strong iron-hooped vessel, to prevent its bursting: it will appear very

thick and muddy when newly pressed; but wil refine in the vessel, and be as clear as wine. Thes let it remain untouched for three months before it is drawn off, and it will prove excellent vinegar.

Method of making cyder into vinegar.—The cyde (the meanest of which will serve the purpose) s first to be drawn off fine into another vessel, and a quantity of the must of apples to be added: the whole is set in the sun, if there be conveniency for it; and at a week or nine days end it may be drawn off.

Method of making wine into vinegar.-Any sort of vinous liquor being mixed with its own fæces, flowers, or ferment, and its tartar first reduced to powder; or else with the acid and austere stalks of the vegetable whence the wine was obtained, which hold a large proportion of tartar; and the whole being kept frequently stirring in a vessel which has formerly held vinegar, or set in a warm place full of the steams of the same, will begin to ferment anew, conceive heat, grow sour by degrees, and soon after turn into vinegar. The remote subjects of acetous fermentation are the same with those of vinous; but the immediate subjects of it are all kinds of vegetable juices, after they have once undergone that fermentation which reduces them to wine; for it is absolutely impossible to make vinegar of must, the crude juice of grapes, and other ripe fruits, without the previous assistance of vinous fermentation. The proper ferments for this operation, whereby vinegar is prepared, are, 1. The faces of all acid wines. 2. The lees of vinegar. 3. Pulverized tartar, especially that of Rhenish wine, or the cream or crystals thereof. 4. Vinegar itself. 5. A wooden vessel well drenched with vinegar, or one that has long been employed to contain it. 6. Wine that has often been mixed with its own fæces. 7. The twigs of vines, and the stalks of grapes, currants, cherries, or other vegetables of an acid austere taste. 8. Bakers' leven, after it has turned acid. 9. All manner of ferments, compounded of those already mentioned.

Acetic acid is the chemical name of the same acid which, in a very dilute and somewhat impure state, is called vinegar.

This acid, says Dr. Ure, is found combined with potash in the juices of a great many plants; particularly the sambucus nigra, phoenix dactilifera, galium verum, and rhus typhinus. Sweat, urine, and even fresh milk contain it. It is frequently generated in the stomachs of dyspeptic patients. Almost all dry vegetable substances, and some animal, subjected in close vessels to a red heat, yield it copiously. It is the result likewise of a spontaneous fermentation, to which liquid vege table and animal matters are liable. Strong acids, as the sulphuric and nitric, develope the acetic by their action on vegetables. It was long supposed, on the authority of Boerhaave, that the fermentation which forms vinegar is uniformly preceded by the vinous. This is a mistake. Cabbages sour in water, making sour crout; starch in starch-makers sour waters; and dough itself, without any previous production of wine.

The varieties of acetic acids known in commerce are four-1. Wine vinegar; 2. Malt vinegar; 3. Sugar vinegar; 4. Wood vinegar. We shall describe first the mode of making these commercial articles, and then that of extracting the absolute acetic acid of the chemist, either from these vinegars, or directly from chemical compounds, of

which it is a constituent. The following is the plan of making vinegar at present practised in Paris:-The wine destined for vinegar is mixed in a large tun with a quantity of wine lees, and the whole being transferred into cloth sacks, placed within a large iron-bound vat, the liquid matter is extruded through the sacks by superincumbent pressure. What passes through is put into large casks, set upright, having a small aperture in their top. In these it is exposed to the heat of the sun in summer, or to that of a stove in winter. Fermentation supervenes in a few days. If the heat should then rise too high, it is lowered by cool air and the addition of fresh wine. In the skilful regulation of the fermentative temperature consists the art of making good wine vinegar. In summer the process is generally completed in a fortnight: in winter double the time is requisite. The vinegar is then run off into barrels, which contain several chips of birch-wood. In about a fortnight it is found to be clarified, and is then fit for the market. It must be kept in close casks.

The manufacturers at Orleans prefer wine of a year old for making vinegar. But if by age the wine has lost its extractive matter, it does not readily undergo the acetous fermentation. In this case acetification, as the French term the process, may be determined by adding slips of vines, bunches of grapes, or green woods. It has been asserted that alcohol, added to fermentable liquor, does not increase the product of vinegar. But this is a mistake. Stahl observed, long ago, that if we moisten roses or lilies with alcohol, and place them in vessels in which they are stirred from time to time, vinegar will be formed. He also informs us, if after abstracting the citric acid from lemon juice by crabs' eyes (carbonate of lime), we add a little alcohol to the supernatant liquid, and place the mixture in a proper temperature, vinegar will be formed.

Chaptal says that two pounds of weak spirits, specific gravity 0.985, mixed with 300 grains of beer yeast, and a little starch water, produced extremely strong vinegar. The acid was developed on the fifth day. The same quantity of starch and yeast, without the spirit, fermented more slowly, and yielded a weaker vinegar. A slight motion is found to favor the formation of vinegar, and to endanger its decomposition after it is made. Chaptal ascribes to agitation the operation of thunder; though it is well known that, when the atmosphere is highly electrified, beer is apt to become suddenly sour, without the concussion of a thunder-storm. In cellars exposed to the vibrations occasioned by the rattling of carriages, vinegar does not keep well. The lees, which had been deposited by means of isinglass and repose, are thus jumbled into the liquor, and make the fermentation recommence. Almost all the vinegar of the north of France being prepared at Orleans, the manufacture of that place has acquired such celebrity as to render their process worthy of a separate consideration.

The Orleans casks contain nearly 400 pints of wine. Those which have been already used are preferred. They are placed in three rows, one over another, and in the top have an aperture of two inches diameter, kept always open. The wine for acetification is kept in adjoining casks, containing beech shavings, to which the lees adhere. The wine thus clarified is drawn off to make vinegar. 100 pints of good vinegar, boiling hot, are first

poured into each cask, and left there for eight days. Ten pints of wine are mixed in, every eight days, till the vessels are full. The vinegar is allowed to remain in this state fifteen days before it is exposed to sale.

The used casks, called mothers, are never emptied more than half, but are successively filled again, to acetify new portions of wine. In order to judge if the mother works, the vinegar makers plunge a spatula into the liquid; and, according to the quantity of froth which the spatula shows, they add more or less wine. In summer the atmospheric heat is sufficient. In winter stoves heated to about 75° Fahrenheit maintain the requisite temperature in the manufactory.

In some country districts the people keep in a place where the temperature is mild and equable a vinegar cask, into which they pour such wine as they wish to acetify; and it is always preserved full by replacing the vinegar drawn off by new wine. To establish this household manufacture it is only necessary to buy at first a small cask of good vinegar.

At Gand a vinegar from beer is made, in which the following proportions of grain are found to be most advantageous:

1880 Paris pounds of malted barley.
wheat.

700 500

buck wheat.

These grains are ground, mixed, and boiled, along with twenty-seven casks-full of river water, for three hours. Eighteen casks of good beer for vinegar are obtained. By a subsequent decoction more fermentable liquid is extracted, which is mixed with the former. The whole brewing yields 3000 English quarts.

In this country vinegar is usually made from malt. By mashing with hot water, 100 gallons of wort are extracted in less than two hours from one boll of malt. When the liquor has fallen to the temperature of 75° Fahrenheit, four gallons of the barm of beer are added. After thirty-six hours it is racked off into casks, which are laid on their sides, and exposed, with their bung holes loosely covered, to the influence of the sun in summer; but in winter they are arranged in a stove-room. In three months this vinegar is ready for the manufacture of sugar of lead. To make vinegar for domestic use, however, the process is somewhat different. The above liquor is racked off into casks placed upright, having a false cover pierced with holes fixed at about a foot from their bottom. On this a considerable quantity of rape, or the refuse from the makers of British wine, or otherwise a quantity of low priced raisins, is laid. The liquor is turned into another barrel every twenty-four hours, in which time it has begun to grow warm. Sometimes, indeed, the vinegar is fully fermented, as above, without the rape, which is added towards the end, to communicate flavor.

Good vinegar may be made from a weak syrup, consisting of eighteen ounces of sugar to every gallon of water. The yeast and rape are to be here used as above described. Whenever the vinegar (from the taste and flavor) is considered to be complete, it ought to be decanted into tight barrels or bottles, and well secured from access of air. A momentary ebullition before it is bottled is found favorable to its preservation. In a large manufactory of malt vinegar, a considerable revenue is derived from the sale of yeast to the bakers.

Vinegar obtained by the preceding methods has more or less of a brown color, and a peculiar but rather grateful smell. By distillation in glass vessels, the coloring matter, which resides in a mucilage, is separated, but the fragrant odor is generally replaced by an empyreumatic one. The best French wine vinegars, and also some from malt, contain a little alcohol, which comes over early with the watery part, and renders the first product of distillation scarcely denser, sometimes even less dense, than water. It is accordingly rejected. Towards the end of the distillation the empyreuma increases. Hence only the intermediate portions are retained as distilled vinegar. Its specific gravity varies from 1.005 to 1.015, while that of common vinegar of equal strength varies from 1.010 to 1.025.

A crude vinegar has been long prepared for the calico printers, by subjecting wood in iron retorts to a strong red heat. The following arrangement of apparatus has been found to answer well. A series of cast-iron cylinders, about four feet diameter and six feet long, are built horizontally in brick work, so that the flame of one furnace may play round about two cylinders. Both ends project a little from the brick work. One of them has a disc of cast-iron well fitted and firmly bolted to it, from the centre of which disc an iron tube about six inches diameter proceeds, and enters at a right angle the main tube of refrigeration. The diameter of this tube may be from nine to fourteen inches, according to the number of cylinders. The other end of the cylinder is called the mouth of the retort. This is closed by a disc of iron, smeared round its edge with clay-lute, and secured in its place by wedges. The charge of wood for such a cylinder is about 8 cwt. The hard woods, oak, ash, birch, and beech, are alone used. Fir does not answer. The heat is kept up during the day time, and the furnace is allowed to cool during the night. Next morning the door is opened, the charcoal removed, and a new charge of wood is introduced. The average product of crude vinegar called pyrolignous acid is thirty-five gallons. It is much contaminated with tar; is of a deep brown color; and has a specific gravity of 1025. Its total weight is therefore about 300 lbs. But the residuary charcoal is found to weigh no more than one-fifth of the wood employed. Hence nearly one half of the ponderable matter of the wood is dissipated in incondensable gases. Count Rumford states that the charcoal is equal in weight to more than four-tenths of the wood from which it is made. The count's error seems to have arisen from the slight heat of an oven to which his wood was exposed in a glass cylinder. The result now given is the experience of an eminent manufacturing chemist at Glasgow. The crude pyrolignous acid is rectified by a second distillation in a copper still, in the body of which about twenty gallons of viscid tarry matter are left from every 100. It has now become a transparent brown vinegar, having a considerable empyreumatic smell, and a specific gravity of 1.013. Its acid powers are superior to those of the best household vinegar, in the proportion of 3 to 2. By redistillation, saturation with quicklime, evaporation of the liquid acetate to dryness, and gentle torrefaction, the empyreumatic matter is so completely dissipated, that on decomposing the calcareous salt by sulphuric acid, a pure, perfectly colorless, and grateful vinegar rises

in distillation. Its strength will be proportional to the concentration of the decomposing acid.

The acetic acid of the chemist may be prepared in the following modes:-1. Two parts of fused acetate of potash with one of the strongest oil of vitriol yield, by slow distillation from a glass retort into a refrigerated receiver, concentrated acetic acid. A small portion of sulphurous acid, which contaminates it, may be removed by redistillation from a little acetate of lead. 2. Or four parts of good sugar of lead, with one part of sulphuric acid treated in the same way, afford a slightly weaker acetic acid. 3. Gently calcined sulphate of iron, or green vitriol, mixed with sugar of lead in the proportion of one of the former to two and a half of the latter, and carefully distilled from a porcelain retort into a cooled receiver, may be also considered a good economical process. Or without distillation, if 100 parts of well dried acetate of lime be cautiously added to sixty parts of strong sulphuric acid diluted with five parts of water, and digested for twenty-four hours and strained, a good acetic acid, sufficiently strong for every ordinary purpose, will be obtained.

The distillation of acetate of copper or of lead per se, has also been employed for obtaining strong acid. Here, however, the product is mixed with a portion of the fragrant pyro-acetic spirit, which it is troublesome to get rid of. Undoubtedly the best process for the strong acid is that first described, and the cheapest the second or third. When of the utmost possible strength its specific gravity is 1:062. At the temperature of 50° Fahrenheit it assumes the solid form, crystallising in oblong rhomboidal plates. It has an extremely pungent odor, affecting the nostrils and eyes even painfully when its vapor is incautiously snuffed up. Its taste is eminently acid and acrid. It excoriates and inflames the skin.

The purified wood vinegar, which is used for pickles and culinary purposes, has commonly a specific gravity of about 1'009; when it is equivalent in acid strength to good wine or malt vinegar of 1014. It contains about one-twentieth of its weight of absolute acetic acid, and nineteen-twentieths of water. An excise duty of four-pence is levied on every gallon of vinegar of the above strength. This, however, is not estimated directly by its specific gravity, but by the specific gravity which results from its saturation with quicklime. The decimal number of the specific gravity of the calcareous acetate is nearly double that of the pure wood vinegar. Thus 1009 in vinegar becomes 1.018 in liquid acetate. But the vinegar of fermentation 1014 will become only 1.023 in acetate, from which, if 0.005 be subtracted for mucilage or extractive, the remainder will agree with the density of the acetate from wood. A glass hydrometer of Fahrenheit's construction is used for finding the specific gravities. It consists of a globe about three inches diameter, having a little ballast ball drawn out beneath, and a stem above of about three inches long, containing a slip of paper with a transverse line in the middle, and surmounted with a little cup for receiving weights or poises. The experiments on which this instrɩment, called an acetometer, is constructed, have been detailed in the sixth volume of the Journal of Science. They do not differ essentially from those of Mollerat. The following points were determined by this chemist :-The acid of specific gravity 1.063

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