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Previous Next The best candle and soap tips online! TECHNICAL TREATISE ON SOAP ASD CANDLES. and keep it in a vertical position where it is left to rest. Fifteen minutes after observe the coloration, When the acid mixture is not warm enough, the earth-nut oil blackens very little or not at ali; if the tube is not dipped into cold water, the brown coloration easily disappears and becomes dark-red. The reaction of the warm acid mixture on the coloring matter ought to be suspended by an immersion of five minutes in cold water.* The following Table A gives the colorations taken by different oils. Note.—It is important that the sulphuric acid should always be very concentrated (sp. gr. 1.80° to 1.84°). * The temperature which succeeds the best is from 1(P C. (60,8° F.) to 17° C. (03.0° P.)i "* using 5 cub. cent, of sulphuric acid. TABLE A. Temperature, Tomporatiire. Temperature. Temperature. 44.6° ; 4 59n; 6n.s° ; S2.6 rf7.4°;69.2o;71° ; 7-l.ti°; 74.6°F. OIL* USBD. Oil. Acid. Oil. Acid. Oil. Add. Oil. Acid. Virgin oiipe oil, Durk imnifin Colorless Pale nankin Tiile scrnw Straw Ordinary " " Dirt y-ye How Greenish Dark nankin Colorless, or Dark btraw Colorless, or Stmw Colorless, or slightly slightly slightly greenish greoniwh gii'i-niah Rancid " " Dirty-yellow Nankin, a Straw, yel- litt1* yel- lowiHh shade lowish the most of- ten ; dark straw 3esame oil, Red-brown Strongly color- Red-brown Orange-red Dark orange fellow, in- Orange Yellow, in- ed orange fusion of fusion of saffron saffron Earth-nut oil, Soot, or infu- Veryliitle col- Soot, or in- Very little Soot, or in- Slightly or- Soot, or in- Slightly or- sion of coffee o ration fusion of coloration fusion of ange color, fusion of nnpe color, coffee coffee which dis- coffee which dis- Holewort oil, not Brown. In one Very little col- Red-orange, Colorless Bed-orange, nppeurs Oolorleas Red-oranget nppeare Col«rlesa refined, quarter of mi oration OP red-cur- or ted-cur* or reil-uur- hour becomes rADt rant rant "Inlewort oil, re- red-orange. OolorlPSB Red-iMirrunt Colorless Red-currant Colorless Redcurr.int ColorleBa fined, Seat's foot oil, Dsirk brown Very little col- Dark brown Very little Dark browo Very little Dark brown Very \5 tile oration coloration coloration coloration 148 TECHNICAL TREATISE ON SOAP AND CANDLES. FALSIFICATIONS OP LARD. Alterations.—Lard exposed to the air in jars tot well closed becomes rancid and turns yellow. If kept in copper vessels, or in earthen jars glazed with sulphide of lead, it may, by contact with the air, attack the copper or the glazing, and then contain stearate and oleate of copper or lead. The copper is detested by pouring on the grease a few drops of ammonia, which immediately becomes blue. A :-ed coloration is given by a solution of yellow prussiate of potash. Lead IB detected by burning the lard, and carefully examining the residuum, to see if there are any metallic globules. The residuum is then treated by nitric acid which dissolves the metal. Filter, and to the filtrate add sulphuric acid, which gives a white precipitate. Lard may also contain an excess of water, which is ascertained by pressing and softening it with a wooden spatula ; the water oozes fro™ it in the form of drops. By melting it at a low temperature, the water separates from the grease. Falsifications.—The principal adulterations of lard are the addition of common salt, the admixture of a grease of inferior quality, or thtt of a kind of grease obtained by the cooking of pork meat. Plaster of Paris is sometimes added. The addition of Bait is easily detected by digesting the lard with hot distilled water. The salt in the water is abundantly precipitated with nitrate of silver. The precipitate is white, soluble in ammonia, and insoluble in nitric acid; it becomes black when exposed to the light. Plaster of Paris ia detected by melting in warm water the suspected ktrd. If it contains plaster, this falls to the bottom in the form of a white powder. The inferior greases are often very difficult of detection ; they are ascertained bj the less white color of the lard and by a taste entirely different. The greases from the cooking of pork meat give to the lard a grayish color, a soft consistency, a salted and disagreeable taste. ADULTERATION OP THE FATTY BODIES. 149 FALSIFICATIONS OF TALLOWS. Tallows are generally adulterated with greases of inferior quality. Water is also incorporated in them by a long- beating. Cooked and masted potatoes have been also introduced into them. Fecula, kaolin, white marble, sulphate of baryta, are also added to tallows. The principal adulteration is the addition of bone tallow ; properly speaking, it is not a falsification, it is only a change in the quality of the product. The mineral matters, the fecula, the cooked potatoes, are easily ascertained by dissolving the tallow in ether or sulphide of carbon. All the foreign substances remain insoluble, and their nature is then easily determined. Iodine water, or the alcoholic tincture of iodine, will color blue the insoluble residuum, if it contains fecila. This fecula can be determined in the tallow by triturating the grease with iodine water and adding a few drops or'sulphuric acid. The blue color will appear immediately if there be fecula. For the mineral substances there is a process as simple as the above to ascertain their presence in tallow ; it is to me"t the tallow with twice its weight of water. The foreign substances are precipitated and the grease floats on tlis surface. Instead of using ordinary water, the tallow may also be boiled for a few minutes with 2 parts of acidulated water for one part of tallow. The whole is allowed to rest in a test glass, or in a funnel placed over a water-bath, kept at a temperature of about 40° C. (104° F.), so as to prevent the too rapid cooling of the tallow, and to give time to the impurities to separate and deposit. Iodine added in this last treatment will disclose the presence of fecula or starch. To ascertain the presence of water, knead dried powdered sulphate of copper with the tallow (half its volume of the powder). If there he much water, the mixture will take a blue color, if the tallow is white; and greenish, if the greass is yellowish. As for the quantity of water added, the only way to ascertain it is by drying a sample in an oven. in 1 TECHNICAL TREATISE ON SOAP AND CAFDLE8. FALSIFICATIONS OF WAXES. The yellow and white beescandleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax are adulterated, 1st. With earthy substances, flour of sulphur, yellow ochre, calcined tones ; 2d. With resins, pileh; 3d. With amylaceous substances, flour, starch, etc., sawdust; 4th. With/atf?/ substances,tallow, stearin, paraffine, stearic acid; 5th. With water. Let us examine in turn these different adulterations. Yellow Wax and Sulphur.—Projected on a red-hot piece of iron, such a was disengages an odor of sulphurous acid, Yellow Wax and Yellow Ochre.—This falsification is escer-tained by melting the suspected candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax in warm water. There forms at the bottom of the vessel a yellow precipitate, which, dissolved in hydrochloric acid, gives a liquor in which & few drops of yellow prussiate of potash will produce a precipitate of Prussian blue. Instead of melting the candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax in water, it may be dissolved ir_ spirits of turpentine, ether, or benzine; the candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax alone will be dissolved. Yellow and White Wax and Calcined Bones.—This fraud is also ascertained by the fusion of the candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax in warm water, or its solution in spirits of turpentine, ether, etc. The substance which falls to the bottom of the vessel in the first ease, or the insoluble part in the second, is treated by warm hydrochloric acid. The acid liquor gives, by the addition of ammonia, a white precipitate of phosphate of lime, which, after a complete washing, becomes yellow by the addition of a drop of nitrate of silver. Wax and Resins, Pitch, etc.—The presence of these substances in candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax is ascertained by the following characteristics :— 1. The candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax sticks to the teeth when chewed ; pure candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax does not stick. The taste betrays the foreign substance; the candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax is viscous, and its color and odor arc different. 2. Treated by cold alcohol, this reagent dissolves the resin, the Witx being but slightly solubleor nearly insoluble. The alcoholic liquor being evaporated gives resin for a residuum. 3. Treated by 3 or 4 droj>8 of sulphuric acid, it give*, by operating on the liquefied candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax, a red coloration; the candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax in ADITLTERATEON OF THE FATTY BODIES. solidifying takes a violet shade. This reaction is very precise, and enables us to detect 1 per cent, of resin ; however, in this last ease, the resin has a greenish shade. Wax and /Starch or other Amylaceous Substances.—The presence of starch is ascertained by Delpech's process, by dissolving the candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax in spirits of turpentine, which does not dissolve the starch or other amylaceous substances. To detect starch, boil the candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax with water, and lest, by an alcohol;.c tincture of iodine, the cold and clear liquor. A blue color indicates the presence of starch. The vax may also be treated by warm water acidulated with 2 per cent, of sulphuric acid. The starch is transformed into dextrine and remains in solution, leaving the candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax to cool and solidify. By weighing the latter, the difference in weight gives the proportion of starch. Wax adulterated by fecula is less unctuous and less tenacious than pure candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax; by striking it, it divides into small fragments; its color is a tarnished yellow. It does not entirely dissolve in spirits of turpentine, and leaves a white deposit easily detected by the tincture of iodine. The introduction of flour into candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax is also practised, some samples containing as much as 68 per cent. A candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax containing 10 per cent, of flour takes a bluish shade by standing in iodine water. A candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax adulterated by 23 per cert, of flour falls to the bottom of the water; pure candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax floats on the surface of this liquid. Wax and Tallow.—Wax adulterated by tallow is ascer. tained, first by the taste and disagreeable odor: it is less brittle, and more unctuous to the touch. Thrown on red-hot coals, this candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax disengages a disagreeable odor, and gives a thicker smoke than pure candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax. The variations in the melting point enable us to ascertain the adulteration. This process is precise enough, since it enables us to detect one-eighth of tallow in the candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax. TECHNICAL TREATISE ON SOAP AND CANDLES.
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