This section is from the book "A Treatise On Beverages or The Complete Practical Bottler", by Charles Herman Sulz. Also available from Amazon: A Treatise On Beverages.
Most of the volatile essential oils met with in commerce are adulterated. These oils embrace a large number employed in manufacturing carbonated beverages. Want of good faith and honesty in certain dealers, who, to increase their profits, make no scruple in cheating the public so long as it requires goods at a low price, are the causes which multiply these adulterations, It is therefore important for the carbonator, if he cannot prepare his own oils, at least to know how to detect the fraud. Almost all the high-priced volatile oils are mixed; some with volatile oils of lower price, others with volatile oils of other substances, and which have lost their color by exposure to the air or by age; some with fixed oils, and, finally, with alcohol and chloroform, etc.
The following is a list of the chief adulterants of some of the principal oils:
Oil of amber with crude petroleum.
Oil of bay with oils of pimento, cloves and nutmeg.
Oil of bergamot, when high in price, with the cheaper oil of sweet orange.
Oil of cade with common tar.
Oil of cajeput with camphor, dissolved in oil of turpentine.
Oil of caraway with oil of the chaff.
Oil of cardamom with oil of cajeput and camphor.
Oil of cassia with fixed oils.
Oil of cedar with oil of turpentine.
Oil of Ceylon cinnamon with oil of cassia and oil of cinnamon leaves.
Oil of croton with cheaper fixed oils.
Oil of cubeb with oil of copaiba.
Oil of rose geranium with the cheaper oil of ginger grass.
Oil of hemlock with oil of turpentime.
Oil of juniper berries with that of the wood, and the latter with oil of turpentine.
Oil of lemon with alcohol and castor oil; also fixed oils. Oil of neroli with petitgrain and bergamot. Oil of orange with alcohol and fixed oils. Oil of patchouly with oils of cedar wood, copaiba and cubebs. Oil of peppermint with oils of turpentine, pennyroyal, and arbor vitse. Oil of petitgrain with oils of sweet orange and bergamot. Oil of rose with oils of citronella, cubeb, rose geranium, copaiba, and also with spermaceti.
Oil of rosemary flowers with oils of cheaper grades. Oil of sassafras with kerosene and oil of turpentine. Oil of sandalwood with balsam copaiba and oil of Florida cedar. Oil of spearmint with oils of pennyroyal and turpentine. Oil of thyme with oil of turpentine. Oil of verbena with that of lemon grass.
Oil of wintergreen with those of turpentine, birch, and also alcohol. The well-known adulterations of musk generally consist of dried blood, and also the same article exhausted with alcohol; while for civet the principal adulteration is stated as honey.