1478. To Detect the Adulteration of a Heavy Oil with a Light One

1478.     To Detect the Adulteration of a Heavy Oil with a Light One. The adulteration of a heavy oil with a light one may bo detected by agitating the suspected sample with water, when, in general, the two will separate and form distinct layers.

1479. To Test the Purity of Essential Oil of Almonds

1479.    To Test the Purity of Essential Oil of Almonds. Essential oil of almonds is very generally adulterated with cheaper oils, particularly nitrobenzole (artificial oil of bitter almonds), and in nearly every case with alcohol or rectified spirit. The pure oil, when mixed with oil of vitriol, turns of a clear crimson - red color, without visible decomposition: - mixed with alcoholic solution of potassa, crystals are eliminated: -iodine dissolves only partially and slowly in it, without further visible results:—chromate of potassa does not affect it:- nitric acid of the specific gravity 1.42 causes no immediate reaction, but crystals of benzoic acid begin to form in 3 or 4 days; if only 7 or 8 per cent. of alcohol be present, violent effervescence speedily commences, and colored nitrous fumes are evolved. Nitric acid of specific gravity 1.5 produces the same effects in a marked degree, even when the smallest quantity only of alcohol is present. The specific gravity of the pure oil, when recent, is never less than 1.052; and when old, never greater than 1.081; that of trade averages about 1.075. Nitrobenzole has the specific gravity 1.209, and its boiling point is 415° Fahr., or fully 100° higher than that of essential oil of almonds.

1480. To Test the Purity of Oil of Bergamot

1480. To Test the Purity of Oil of Bergamot. Oil of bergamot is very frequently adulterated with rectified spirit, or with the oil of lemon, orange peel, and turpentine. These may be detected in the way previously noticed. (See No. 1476 (To Detect the Presence of Alcohol in Essential Oils), etc..) The presence of the foreign oils, particularly the last, lessens its solubility in rectified spirit. The pure oil is freely soluble in liquor of potassa, forming a clear solution. Its specific gravity is .875 to .885.

1481. To Test the Purity of Oil of Cinnamon

1481. To Test the Purity of Oil of Cinnamon. The common adulterants are highly rectified spirit and oil of cassia. When pure, its specific gravity is 1.035. Oil of cassia, of which the specific gravity is 1.071 to 1.073, and when old, even 1.078 to 1.090, increases it; but before trying it, it must be tested for spirit, which has a contrary effect.

1482. To Test the Purity of Oil of Lavender

1482.    To Test the Purity of Oil of Lavender. Alcohol is here also the common adulterant. The finest quality - that from the flowers, has specific gravity .877 to .905. The lightest is esteemed the best. Santaline is insoluble, or very nearly so, in the pure oil, but is freely soluble in that adulterated with alcohol. The presence of oil of turpentine, and other inferior oils, may be detected by the blotting-paper test, noticed above. (See No. 1475 (To Detect the Presence of Fatty Oil and Resins in Essential Oils).