It is imitated by adding acetic ether and coloring | matter to vinegar made from whiskey. Cider Vinegar (which includes all fruit vinegars) contains malic acid. Malt, or Corn Vinegar, made from weak worts, contains phosphates of lime and magnesia, gum, and extractive matter. Wood Vinegar, or pyroligneous acid, when crude, contains tar and wood spirit. Adulterations of Vinegar. Sulphuric, nitric and muriatic acids, are used to give a false strength; burned sugar and acetic ether to give color and flavor. The latter cannot be considered as injurious. One one-thousandth of mineral acid is allowable, and tends to preserve the vinegar. This would be about four measured ounces to the barrel, or two to the ordinary halfbarrel. Sulphuric acid is detected by boiling with chloride of calcium; baryta is not admissible as a test for sulphuric acid in vinegar. Muriatic acid gives a white, curdy precipitate, with a solution of nitrate of silver. This precipitate is soluble in ammonia, and blackens on exposure to light. Nitric acid is detected by adding muriatic acid. If the solution will dissolve gold leaf, nitric acid is present. To Strengthen Vinegar. Freeze it and remove the ice which forms on the surface. The water of the vinegar alone freezes, leaving the acetic acid in solution in the remaining water. To Determine the Strength of Vinegar. The hydrometer (see SPECIFIC GRAVITY) is not to be much relied on in testing the strength of vinegar. The simplest test is to take a fragment of fine marble, weigh it and suspend it by a thread in a known measure of vinegar until all action ceases and the liquid has no longer a sour taste. Take out the marble, wash and dry it, and note the loss of weight it has sustained. Fivesixths of this is real (hydrated) acetic acid. An ounce of good vinegar should saturate from 30 to 32 grs. of pure and dry carbonate of soda; such vinegar contains about 5 per cent. of anhydrous (absolute) acetic acid. Vinegar above 30 per cent. of real acid will dissolve the essential oils and camphor. Simple continuous Vinegar Process. The following household vinegar method is to be recommended as simple, expeditious, and furnishing a constant supply of vinegar with scarcely any trouble, and at trifling cost: Two barrels are procured, one for making, the other for storing the vinegar. Those from which good vinegar has just been drawn are preferable. The storage barrel is kept always in the cellar, the generating one in the cellar or house, according to the season. In this latter barrel a small hole is bored, for the circulation of air, at the top of one of its heads. The barrels lie on their side, and contain each a wooden fancet. Of course their capacity is regulated by the yearly demand of vinegar. We will suppose that the generator, filled to the fevel of the ventilating hole, contains 10 galls.; the manufacture will then be carried on in the following manner: Seven galls. of good vinegar are placed in it, and 3 galls. of a warm alcoholic mixture made in the following manner and added: If common whiskey (50 per cent.) be employed, have a small measure of 3 pts. and a large one (a bucket) of 3 galls. If 86 per cent. spirits are used, let the small measure be for 2 pts. Put a small measureful of the spirits in the large mea sure; fill quickly to the mark with boiling water, and pour by a funnel into the generator. Every 2 or 3 weeks 3 galls. of vinegar are withdrawn from the generator, added to the storage barrel, and 3 galls. of alcoholic mixture are placed in the generating barrel as before. Another method of working the casks consists in half filling the generator with vinegar and adding every week so much of the alcoholic mixture that it fills the barrel in from 8 to 16 weeks, according to the season. Half the vinegar is then added to the storage cask, and the process recommenced in the generator. The warmer the season the more rapid may be the manufacture.Wetherill on the Manufacture of Vinegar. Vinegar without a Ferment (Dobereiner's Process). The ferment used in the manufacture of vinegar is not necessary. Alcohol may be oxidized directly by the agency of finely divided platinum (platinum black); 10 per cent. alcohol placed in a close vessel with platinum black is rapidly converted into acetic acid. Dr. Ure estimates that with a box of 12 ft. cube and 6 to 8 oz. of strong platinum, 1 lb. of alcohol daily can be converted into acetic acid, and with from 20 to 30 lbs. we may obtain 300 lbs. of vinegar from the proportionate quantity of spirits. The same platinum black will last for an indefinite time, requiring only to be heated to redness from time to time, to restore it. This method is undoubtedly the most has been tried on a large scale in Germany. The elegant one known of vinegar manufacture, and objection to it is, however, the high cost of the platinum, in which a large amount of capital must necessarily be kept locked up. The continuous Quick Vinegar Process. This is the method almost universally adopted for manufacturing vinegar on the large scale. Common new whiskey makes excellent vinegar; the fusel oil becoming oxidized during the process, is converted in harmless, agreeable ether. It is alcohol. Two tubs, or upright casks, are prepared diluted so as to form a wash of about 6 per cent. as follows: A false top and bottom are inserted. In the false top are bored numerous holes onetenth of an inch in diameter and 14 in. apart; the top is fixed water-tight about 6 to 8 in. from the top of the barrel. At from 8 to 14 in. above the bottom of the tube are bored in. air-holes, inclining downwards, so that the liquid may not flow out. About 2 in. above the air-holes is placed the false bottom pierced within. or inch holes. The space between the false top and bottom is filled with closely-curled beech-shavings, or charcoal in lumps of the size of a walnut, sifted, washed and dried. The holes in the false top are filled with lamp-wick, and the space below the false bottom provided with a stop-cock, or gooseneck. There is also an inclined hole 6 in. below the false top for the insertion of a thermometer and hour-glass, or wood tubes are inserted into the false top, reaching nearly to the cover of the tub; these act as chimneys. The beech shavings are boiled in vinegar and pressed into their place until within 6 in. of the false top or sieve. Before starting the process the room and tubs are to be kept a day at a temperature of 75° to 80° Fahr. The shavings at the thermometer hole, and at the lower ventilating holes, are then loosened by means of a stick thrust therein. A wash is now prepared which contains 1-5 vinegar and 4-5 of a 3 per cent. solution of alcohol; this heated to from 750 to 80°, is gradually poured through the hole in the cover of the generator, at the rate of 1 barrel in 24 hours. At the expiration of this time, warm the resulting vinegar if necessary, and hav in a furnace, so that it may receive as much heat, all round, as possible. One end of this cylinder must be so constructed as to open and shut, to admit wood, and exclude the air. ing added enough alcohol to make the whole | lar to those used for the production of coal gas), quantity taken thus far of 5 per cent. alcoholic strength, pour this through the generators as before. Repeat this operation on the third, and even on the fourth day if necessary. Investigate the temperature of the air escaping from the generator, and when it exceeds that of the wash which is running, it is a sign that the acetification has commenced. When it rises to a point between 98° and 104°, the generators are in a proper condition to commence the regular business of the manufacture; the fermentation has been properly established. We then daily pour through generator No. 1, a wash consisting of a certain quantity of spirits, vinegar, and water, heated to a temperature between 75° and 80° Fahr.; and through No. 2 the wash has passed through No. 1, to which has been added more spirits. We draw manufactured vinegar daily from generator No. 2. The vinegar resulting from setting the generators in action, though not prejudicial to health, is of inferior quality and bad flavor, from extractive matter from the shavings and tubs and from the iron cauldron. It may be added in very small quantity to the subsequent vinegar, if it be not thrown away.-Wetherill on the manufacture of vinegar. To make Quas8. Mix rye flour and warm water together, and leave it till it has turned sour. This vinegar is much drunk in Russia; it looks thick and unplea sant at first, but becomes agreeable by use. Distilled Vinegar. This is obtained from vinegar by distillation, rejecting the fourth or eighth part that comes over first, and avoid its acquiring a burnt flavor. Distilled vinegar is weaker than the common, but is used sometimes in pickles, where its want of color is an advantage. To Deprive Vinegar and other Vegetable Liquids of their Color. To take away the color of vinegar, a litre of red wine vinegar, cold, is mixed with 45 grammes of bone-charcoal, in a glass vessel. Shake this mixture from time to time, and in 2 or 3 days the color completely disappears. When the process is to be performed in the large way, throw the charcoal into a cask of vinegar, which must be stirred from time to time. The highest colored red wines treated in the same manner become perfectly limpid. Ivory-black possesses the same property as bone-black. To Prepare the Charcoal. Fill a crucible with the most compact parts of ox and sheep bones, lute the cover, carefully leaving only a small opening at the top, place the crucible on a forge fire, and heat it gradually till red; when the flame from the oily and gelatinous parts has ceased, diminish the opening and suddenly raise the fire; when cold, reduce the charcoal to fine powder. Oak, in pieces about 1 foot in length. is to be put into the cylinder, which is to be filled as full as possible, without being wedged, and the door must be shut close to exclude air; from the cylin der let a worm run through cold water to condense the acid; by this it is conveyed to a large cask placed on one end, where there is a pipe to carry it from that to 2 or 3 more; thus it is completely secured from flying off in the vaporous state. The fire is now to be raised to a great heat, sufficiently powerful to convert the wood completely into charcoal. When the acid ceases to come over, the fire is to be taken out, and the mass of wood left to cool in the confined state, when it becomes perfect charcoal. In the first cask, tar is chiefly contained with the acid, it precipitates to the bottom, and is drawn off by a cock; it is afterwards boiled in an iron boiler to evaporate the acid, before it is fit for use. If the acid is not strong enough, it is put into large square vats about 6 inches deep, for the purpose of making a large surface, to evaporate a part of the water contained in the acid, more especially by a slow heat. These vats are bedded on sand upon the top of a brick stove, where a gentle heat is applied; thus it may be procured in a pretty strong state. This acid is a liquid of the color of white wine, possesses a strong acid and slightly astringent taste, combined with an empyreumatic smell. When allowed to remain in a state of rest for 8 or 10 days, tar of a black color subsides, and the acid is then comparatively transparent. To purify it further, it undergoes the process of distillation, by which it is freed from a still greater portion of the tar, with which it is combined, and is thus rendered still more transparent. But though the process of distillation be repeated without end, it will never be freed from the volatile oil with which it is combined, and which is the cause of empyreuma constantly attending it. In short, it contains the same properties for the preservation of animal matters from putrefaction as smoking them by wood does, which is practised at present by the most barbarous nations, and which has been handed down from the remotest ages of antiquity. Glacial Acetic Acid (Ice Vinegar). To 83 lbs. of fused acetate of soda add 100 lbs of sulphuric acid and distill. Place the distillate in ice at 50° Fahr., it will become solid. Allow it to drain. It is the monohydrated acid. Oil of Vitriol. The strongest or Nordhausen or fuming acid is made by distilling green vitriol at a red heat. The residue is colcothar or crocus martis. It is used for dissolving indigo and other purposes where an acid of great strength is required. The ordinary To Procure Pyroligneous Acid. sulphuric acid is made by causing vapors of sulThis acid is procured from any kind of green and water, to combine in a leaden chamber. The phurous acid (from burning sulphur), nitric acid wood (such as cord wood), used for making char-weak acid is concentrated in leaden pans, and coal; a cord of wood will produce about 80 galls. afterwards in a platinum still. It is obtained in the following manner: A brisk oven is filled with coal or wood, until it becomes Eufficiently hot to heat an oven over it to that degree as to reduce green wood to a charcoal. The upper oven should be closely stopped except a tube at the top to carry off the steam or acid, which tube is passed through water, and the steam thus condensed forms the acid. To Prepare the same. Nitric Acid, Or aqua fortis, may be made by distilling at a gentle heat in a glass retort, equal weights of saltpetre (nitrate of potassa), and sulphuric acid. The receiver should be kept cooled by a cloth dipped in water. To obtain it pure it must be redistilled over nitrate of silver. Hydrochloric Acid, Or muriatic acid (marine acid, spirit of salt) TEST LIQUORS, TEST PAPERS, ETC. Distilled water only should be used in these preparations. In preparing the papers the liquid should be placed in an earthenware plate or dish, and the paper carefully immersed in it so as to be uniformly wetted, then dried out of the reach of acid, ammoniacal, or other vapors likely to affect it; and afterwards kept in bottles, jars, or cases. Brazil Paper. Dip paper in a strong decoction of Brazil wood, and dry it. [It is rendered purple or violet by alkalies; generally yellow by acids.] Cabbage Paper. Make a strong infusion of red cabbage leaves, strain it, and evaporate it by a gentle heat till considerably reduced. Then dip the paper in it and dry it in the air. [This paper is of a grayish color; alkalies change it to green, acids to red. It is a very delicate test; if rendered slightly green by an alkali, carbonic acid will restore the color.] Dahlia Paper. From the petals of violet-dahlias, as cabbage paper. Elderberry Paper. This is merely paper stained with the juice of the berries. Its blue color is changed to red by acids, and to green by alkalies. Indigo Paper. Immerse paper in sulphate of indigo, wash it with water rendered slightly alkaline, then with pure water, and dry it in the air. Iodide of Potassium and Starch Paper. Mix starch paste with solution of iodide of potassium, and moisten hibulous paper with it. It becomes blue when exposed to ozone. Chlorine has the same effect.] Lead Paper. Paper dipped in a solution of acetate of lead. [When moistened it delects sulphuretted hydrogen, which renders it black. Blue Litmus Paper. Bruise 1 oz. of litmus in a mortar, and add boiling water; triturate together, put them in a flask and add boiling water to make up to half a pint; when cool strain it, and dip paper in it. More color may be extracted from the litmus by hot water, but the liquid will require to be concentrated by evaporation. [Acids change the color to red, but it does not become green with alkalies.] Red Litmus Paper. As the last, adding to the strained infusion few drops of nitric acid, or of pure acetic acid. Rose Paper. Make a strong infusion of the petals of the red rose, and dip unsized paper in it. [Dipped in an alkaline solution so weak as not to affect turmeric paper, it assumes a bright green color.] Manganese Faper. Dip paper in a solution of sulphate of manganese. [It becomes black in an ozonized atmosphere.] Rhubarb Paper. Dip paper in a strong infusion of rhubarb, and dry it. [Alkalies render it brown. It is not, like turmeric paper, affected by boracic acid.] Starch Paper. This is merely paper imbued with starch paste. Cotton cord is sometimes used instead of paper. [As a test for iodine, which turns it blue.] Turmeric Paper. Boil 1 oz. of coarsely powdered turmeric root in a pint of water for an hour, and strain; dip paper in the liquid and dry it. [It is rendered brown by alkalies, and also by boracic acid and borates.] SALINE CARBONATED WATERS. The following afford approximate imitations of these waters. The earthy salts, with salts of iron, should be dissolved together in the smallest quanThe other ingredients to be distity of water. solved in the larger portion of the water, and the solution impregnated with gas. The first solution may be then added, or be previously introduced into the bottles. The salts, unless otherwise stated, are to be crystallized. Baden Water. Chloride of magnesium, 2 grs.; chloride of calcium, 40 grs.; sesquichloride of iron, gr. (or 3 minims of the tincture); common salt, 30 grs.; sulphate of soda, 10 grs.; carbonate of soda, 1 gr.; water, 1 pt.; carbonic acid gas, 5 volumes. Carlsbad Water. Chloride of calcium, 8 grs.; tincture of chloride of iron, 1 drop; sulphate of soda, 50 grs.; carbonate of soda, 8 grs.; carbonated water, 1 pt. Eger. Carbonate of soda, 5 grs.; sulphate of soda, 4 scruples; chloride of sodium, 10 grs.; sulphate of magnesia, 3 grs.; chloride of calcium, 5 grs.; carbonated water, 1 pt. Or it may be made without the apparatus, thus:-Bicarbonate of soda, 30 grs.; chloride of sodium, 8 grs. ; sulphate of magnesia, 3 grs.; water, 1 pt. Dissolve, and add a scruple of dry bisulphate of soda, and close the bottle immediately. Ems. bonated, 1 pt. One of the most active of the purgative saline waters. Pullna Water, without the Machine. Bicarbonate of soda, 50 grs.; sulphate of magnesia, 4 drs.; sulphate of soda, 3 drs.; common salt, 1 scruple. Dissolve in a pint of water; add, lastly, 2 scruples of bisulphate of soda, and close the bottle immediately. Salts for Making Pullna Water. Dry bicarbonate of soda, 1 oz.; dried sulphate of soda, 2 oz.; dried sulphate of magnesia, 14 oz. ; dry common salt, 2 drs.; dry tartaric acid, oz. (or rather, dry bisulphate of soda, 1 oz.). Seidlitz Water. This is usually imitated by strongly acrating a solution of 2 drs. of sulphate of magnesia in a pint of water. It is also made with 4, 6, and 8 drs. of the salts to a pint of water. Seidlitz Powder. The common Seidlitz powders do not resemble the water. A closer imitation would be made by using effloresced sulphate of magnesia instead of the potassio-tartrate of soda. A still more exact compound will be the following:-Effloresced sulphate of magnesia, 2 oz.; bicarbonate of soda, oz.; dry bisulphate of soda, oz. Mix and keep in a close bottle. Seltzer Water. Chloride of calcium and chloride of magnesium, of each 4 grs. Dissolve these in a small quantity of water, and add it to a similar solution of 8 grs. bicarbonate of soda, 20 grs. common salt, and 2 grs. of phosphate of soda. Mix, and add a solution of of a gr. of sulphate of iron. Put the mixed solution into a 20-oz. bottle, and fill up with aerated water. But much of the Seltzer water sold is said to be nothing more than simple carbonated water. An imitation of Seltzer water is also made by putting into a stone Seltzer bottle, filled with water, 2 drs. bicarbonate of soda, and 2 drs. of citrate acid in crystals, corking the bottle immedately. Soda powders are sometimes sold as Seltzer powders. Vichy Water. SULPHURETTED WATERS. Simple Sulphuretted Water. Pass sulphuretted hydrogen into cold water (previously deprived of air by boiling, and cooled in a closed vessel), till it ceases to be absorbed. Aix-la-Chapelle Water. Bicarbonate of soda, 12 grs.; common salt, 23 grs.; chloride of calcium, 3 grs.; sulphate of soda, 8 grs.; simple sulphuretted water, 24 oz.; water slightly carbonated, 174 oz. Bareges Water. Crystallized hydrosulphate of soda, crystallized carbonate of soda, and common salt, of each 24 grs.; water (freed from air), 1 pt. A stronger solution for adding to baths is thus made:-Crys tallized hydrosulphate of soda, crystallized carbonate of soda, and common salt, of each 2 oz.; water, 10 oz. Dissolve. To be added to a common bath at the time of using. Naples Water. Crystallized carbonate of soda, 15 grs.; fluid magnesia, 1 oz.; simple sulphuretted water, 2 oz.; aerated water, 16 oz. Introduce the sulphuretted water into the bottle last. Harrowgate Water. Common salt, 100 grs.; chloride of calcium, 10 grs.; chloride of magnesium, 6 grs.; bicarbonate of soda, 2 grs.; water, 18 oz. Dissolve, and add simple sulphuretted water, 14 oz. CHALYBEATE WATERS. Aerated Chalybeate Water. Sulphate of iron, 1 gr.; carbonate of soda, 4 grs.; water deprived of air, and charged with carbonic acid gas, 1 pt. Dr. Pereira recommends 10 grs. each of sulphate of iron and bicarbonate of soda to be taken in a bottle of ordinary soda water. This is equivalent to 4 grs. of carbonate of iron. Brighton Chalybeate. Sulphate of iron, common salt, chloride of calBicarbonate of soda, 1 dr.; common salt, 2 grs.;cium, of each 2 grs.; carbonate of soda, 3 grs.; sulphate of soda, 8 grs.; sulphate of magnesia, 3 carbonated water, 1 pt. grs. tincture of chloride of iron, 2 drops; aerated water, 1 pt. Dorvault directs 75 grs. of bicarbonate of soda, 4 grs. of chloride of sodium, onefifth of a gr. sulphate of iron, 10 grs. sulphate of soda, 3 grs. sulphate of magnesia, to 1 pt. of water. By adding 45 grs. (or less) of citric acid an offervescing water is obtained. M. Soubeiran, relying on the analysis of Longchamps, imitates Vichy water by the following combination: - Bicarbonate of soda, 135 grs.; chloride of sodium, 2 grs.; cryst. chloride of calcium, 12 grs.; sulphate of soda, 11 grs.; sulphate of magnesia, 3 grs.; tartrate of iron and potash,gr.; water, 2 and one-tenth pts. (1 litre); carbonic acid, 305 cubic inches (5 litres). Dissolve the salts of soda and iron in part of the water, dissolve and add the sulphate of magnesia, and then the chloride of calcium in the remaining water. Charge now with the carbonic acid gas under pressure. Vichy Salts. Bussang, Forges, Provins, And other similar waters, may be imitated by dissolving from to of a gr. of sulphate of iron, 2 or 3 gr. of carbonate of soda, 1 gr. of sulphate of magnesia, and 1 of common salt, in a pint of aerated water. Bicarbonate of soda, 14 oz.; common salt, 15 grs.; effloresced sulphate of soda, 1 dr.; effloresced sulphate of magnesia, 1 scruple; dry tartarized Take of tartaric acid, oz.; loaf sugar, 3 oz.; sulphate of iron, 1 gr.; dry tartaric acid, 1 oz. (or essence of lemon, dr. Powder the tartaric acid dry bisulphate of soda, 1 oz.). Mix the powders, and the sugar very fine, in a marble or wedgepreviously dried, and keep them in a close bottle.wood mortar (observe never to use a metal one), mix them together, and pour the essence of lemon upon them, by a few drops at a time, stirring the mixture after each addition, till the whole is added; then mix them thoroughly, and divide it into 12 equal parts, wrapping each up separately in a piece of white paper. When wanted for use, it is only necessary to dissolve it in a tumbler of cold water, and fine lemonade will be obtained, containing the flavor of the juice and peel of the lemon, and ready sweetened. FIXED OILS. To make Oil of Sweet Almonds. It is usually made from bitter almonds for cheapness, or from old Jordan almonds, by heat, the oil from which soon grows rank, while that from fresh Barbary almonds, drawn cold, will keep good for some time. The almonds are sometimes blanched by dipping in boiling water, or by soaking some hours in cold water, so as to part with their skin easily; but are more usually ground to a paste, which is put into canvas bags, and pressed between iron plates in a screw press, or by means of a wedge; 1 cwt. of bitter almonds, unblanched, produces 46 lbs. of oil; the cake pays for pressing. Is obtained from nutmegs by the press. It is buttery, having the smell and color of mace, but grows paler and harder by age; 2 lbs. of nutmegs in Europe will yield 6 oz. of this oil. True Oil of Mace by Expression. This oil is red, remains always liquid or soft, has a strong smell of mace, subacid taste, and is imported in jars or bottles, the lower part being rather thicker than the top; 14 lbs. of mace will yield in Europe 1 oz. troy of oil. Olive, Salad, or Sweet Oil. This is the most agreeable of all the oils; it is demulcent, emollient, gently laxative, and is also used as an emetic with warm water; dose, 1 oz. troy, or a large spoonful; also externally, when warm, to the bites of serpents, and, when cold, to tumors and dropsies. Rank oil is best for plasters, but fresh oil makes the best hard soap. Castor Oil Is made by pressing the beans, cold or slightly warmed. It may be rendered colorless and odorless by filtering through animal charcoal and magnesia. It is soluble in strong alcohol, and is used as the basis of many hair-oils. (See PERFUMERY.) Oil of Croton. This oil is extracted from Molucca grains, or purging nuts. In its chemical qualities it agrees with castor oil, but is considerably more active, as a single drop, when the oil is genuine, is a powerful cathartic. Rape Oil. This is made from rape-seed. It dries slowly, and makes but a softish soap, fit for ointments. The mucilage it contains may be got rid of, in a great measure, by adding ounce of oil of vitriol to 2 pts. of the oil. Begin by washing the oil with spring-water; which is effected by agitating the oil violently with a sixth part of the water. This separates the particles of the oil, and mixes those of the water intimately with them. After this operation it looks like the yolk of eggs beat up. In less than 48 hours they separate completely, the oil swimming at the top, the water, with all feculent and extraneous particles, subsiding to the bottom. This may be very much improved, by substituting seawater in the place of fresh-water. By the process of washing the oil does not lose a hundredth part. The experiment can at all times be made in a glass decanter, or in a churn, with a cock at the bottom, the water to come up very near to the cock, by which all the oil can be drawn off, after it has deposited its impurities. Another Method. To 100 parts of oil add 1 or 2 of concentrated sulphuric acid, and mix the whole well by agitation, when the oil will become turbid, and of a blackish-green color. In about three-quarters of an hour the coloring matter will begin to collect in clots; the agitation should then be discontinued, and clean water, twice the weight of the sulphuric acid, be added. To mix the water with the oil and acid, a further agitation of half an hour will be requisite. The mass may, afterwards, be left to clarify for 8 days, at the end of which time 3 separate fluids will be perceived in the vessel; the upper is the clear oil, the next is the sulphuric acid and water, and the lowest a black mud or fecula. Let the oil then be separated by a syphon from the acid and water, and filtrated through cotton or wool. It will be nearly without color, smell, or taste, and will burn clearly and quietly to the last drop. To Purify Vegetable Oil. To 100 lbs. of oil add 25 oz. of alum, and mix, dissolved in 9 lbs. of boiling water. After stirring it about half an hour, add 15 oz. of nitric acid, still continuing to stir it. Let it stand 48 hours, when the fine oil will swim on the surface, and then draw it off. Such oil is used all over the Continent, and an equal quantity yields double the light of whale and fish-oil, without its offensive odor. This is obtained like the rest of the animal fats, from the raw lard, by chopping it fine, or rather rolling it out, to break the cells in which the fat is lodged, and then melting the fat in a waterbath, or other gentle heat, and straining it while warm. Some boil them in water; but the fats thus obtained are apt to grow rank much sooner than when melted by themselves. Neat's-foot, or Trotter Oil. Obtained by boiling neat's-fective, etc. in |