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Previous Next The best candle and soap tips online! 0° P.), and solidifies at —253 C. (13° below 0° F.\ while poppy oil begins to solidify between 3.9° C. (39° F.)and 6° 0. (42.8° F.). One part of aqua ammonia mixed with 9 parts of oil of sweet almonds forms a white soft soap, very smooth and homogeneous, if the oil be pure; on the contrary, it is clotted if it contains more than one-fifth of poppy oil. RAPESEED OIL. This oil is falsified with linseed, mustard, and whale oils, oleic acid, etc. Ammonia with pure oil gives a milk-white soap; and a yellowish-white soap, when the mustard and whale oils are present. Gaseous chlorine colors rapeseed oil brown, when it contains whale oil; if pure, it remains colorless. SESAME OIL. This oil is ordinarily mixed with earth-nut oil. LINSEED OIL. This oil is falsified with hempseed oil, and especially with iish oil. Pure linseed oil treated by hyponitric acid becomes pale pink ; by ammonia, dark yellow, and gives a thick and homogeneous soap. BLACK POPPY OIL. This oil is often, mixed with sesame and beech-nut oils. The pure oil is colored a light yellow with hyponitric acid, while beech oil acquires a pink color. Ammonia color3 it a light yellow ; the consistency is slightly thick, and the soap is a little granular. HfiifPSEED OlL, The adulteration of this oil is always done with linseed oil. The pure oil treated by ammonia becomes yellow, thick, and granular. TECHNICAL TREATISE OS SOAP AND CANDLES. CASTOB OIL ? is generally mixed with black poppy oil. The adulteration is easy to detect with alcohol at 9i>D B.; a certain quantity of oil agitated with this liquid is dissolved and leaves the foreign oil as a residuum. NEAT'S FOOT OIL. This oil is without doubt the moat adulterated oil found in commerce; it is mixed with whale, black poppy oil, and oleiu. OLEIC ACID. This acid is often mixed with rosin oil. The pure acid, treated with an acid solution of nitrate of mercury, yields a pale straw-colored foam; the rosin oil yields a very dark orange foam. PALM OIL. Tiiis oil has been mixed with or manufactured entirely of yellow candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax, lard, mutton suet, colored with turmeric, and aromatized with powdered orris root, without any genuine palm oil. By treating the suspected oil with ether, all the fatty bodies are dissolved; the turmeric and orris root remain insoluble. By sapouification the mixed or artificial oil takes a reddish shade due to the action of the alkali on turmeric. Sometimes powdered rosin has been mixed with it; thia falsification is easily detected by treating the oil with alcohol: the rosin is dissolved while the oil remains insoluble COCOA-KUT OCL. The commercial oil is often adulterated with mutton suet, beef marrow, or other animal greases, sometimes also with the oil of sweet almonds and candleshop.com/cgi-bin/affiliates/clickthru.cgi?id=soforreal">wax. The oil falsified by these substances does not completely dissolve in cold ether. The ethereal solution is muddy like that given by pure butter. ADULTERATION OF THE FATTY BODIES. The oil thus falsified has a taste and an odor less agreeable, a color rather grayish than yellowish, and has less cousist-ency. The melting point is the beat method of ascertaining the purity. Adulterated with greases or tallows the oil melts at 2G° to 28° U (78.8° to 82.4° F.); with oil of sweet almonds it melts at 23° C. (73.4° F.). ASSAYS OF OILS. Fatty oils are characterized by certain special properties, by which it i& easy to determine tlieir purity, or to know in what proportions they are mixed. All retain in solution substances, whieli become colored under the influence of certain chemical agents. These substances may acquire a special coloration only by operating nt a known temperature. The discoloration is about the same if we operate on oils of the same kind, obtained at the ordinary temperature, or at a higher temperature thai! that of the atmosphere. By old oils, we understand, those which, though prepared for some time, have been placed in good conditions of conservation. Olive oil, for example, placed for one or two years in a warm place, kept in a vessel half full, and exposed to the contact of the air, if tested in a certain manner, is colored like the oil of sesame. This discoloration indicates a decided alteration of the substance it holds in solution. This characteristic may be met with in the oil used in manufactures, never in that employed for food. The latter is generally colorless, or very little colored. By some other modes of testing, this oil behaves like one which lias been well preserved, or has been recently obtained. Several authors have spoken of coloration, but their processes to produce these colorations are difficult; besides, the colorations obtained are not characteristic enough :o enable us to determine the purity of a eommerci.il oil. We must understand by this name, the oil as it is usually prepared in the arts. The following processes are easy of employment: 144 TECHNICAL TREATISE ON SOAP AND CANDLES. With the oil tried, a coloration ought to be produced similar to that assumed by the same kind of oil placed in similar conditions. If there is a mixture, the coloration obtained will be proportional to the volume of each oil in the mixture. We know that fatty oils are formed of fatty acids, and glycerin; that these combinations are more or less stable according to the conditions of conservation of the oils; lastly, that by the nitrogenous substances they contain, substances which play the part of a ferment, the glyceric combinations are decomposed into glycerine and fatty acids. If an aqueous solution of potash is made to act at the ordinary temperature on a rancid non-siccative oil, the fatty acids set free unite first with the potash; then the alkali has its action on the undecomposed compounds. If the same oil, but not rancid, ie treated in the same manner with potash, the alkali reacts at first on the combinations which in rancid oil are decomposed bj the ferment. If we treat a commercial oil at the ordinary temperature for thirty seconds, by a solution of potash, and afterwards if this mixture is acted upon by an alcoholic solution of bromine, this substance is absorbed by the fatty substance much quicker than if it had not been saponified. This absorption is ussisted by a more complete saponification, and it takes place with a production of heat which varies for every kind of oil. We shall now enter into some details in regard to the processes of assaying oila. QUALITATIVE ASSAYS. First Process.—It consists in allowing a mixture of warm aqueous sulphuric acid and concentrated nitric acid to react on oila for 30 seconds. The quantity of acid to be used variea according to the temperature at which the operation is conducted. At 7° C. (44.6° F.), 8° C. (46.4° F.), 9° C. (48.2° F.), the quantities to be taken are— ADULTERATION OF THE FATTY BODIES. 145 1st. Suiphuricaeidsp.gr. 1.80 to 1.84 (65° to 6&o B.) ... 7 cub. c£nt. (1.89 flu. dr.) 3d. Water 3 " (0.81 flu. dr ) 3d. Oil 4 " (1.08 flu. dr.) 4th. Nitric acidsp. gr. 1.35 to 140 (85° to40°B.) 3 " At 10° C, (50° F.), 11° G. (51.8° F.), 12° C. (53.6° F.), 13° C. (55.4° F.), 14° C. (57.2° F.),take let. Sulphuric acid .... 6 cub. cent. (1.C3 flu. dr.) 2d. Water 3 " 3d. Oil .4 " 4tii. Nitric acid 3 " At 15° C. (59° F.), 166 C. (60.s° F.), 17° C. (62.6C F.), 18° C. (64.4° F.), lb° C. (66.1° F.), take 1st. Sulphuric acid .... 5 cub. cent. (1.85 flu. dr.) 2d. Water 8 " 3d. Oil 4 4th. Nitric acid 3 " At 20° C. (68° F.), 21° C. (69.8° F.), 22° 0. (71.6° F.), 23° C. (73.4° F.), 24° C. (75.2°), take 1st. Sulphuric acid .... 4 cab. cent. 2d. Water 3 " 3d. Oil 4 » 4th. Nitric acia 3 " (0.81 flu. dr.) Measure in a graduated tube the sulphuric acid, which is introduced into a test-tube closed at one end, 20 cenrimetrea (T.9 inches) iu height, and 18 millimetres (0.70 inch) in diameter. Let 'the acid drain well, then, in the same tube, Treasure the water which is poured upon the acid, and mix quickly by shaking the tube, The produced heat ought to r&ngo from 44° C. (111.2° F.) to 48° C. (118.4° F.). Into this warm mixture pour the oil which baa been measured in another graduated tube. Lastly, add the nitric acid care-felly measured. Apply a sheet of India rubber to tlie opening of the tube and shake it strongly for 30 seconds, then flip it immediately into cold water, where it is left for five minutes. The oil collects at the surface of the liquid and begina to be colored. After five minutes, remove the tube lft 140 Previous Next
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