82 



THE ALUMNI JOURNAL. 



the comparative amount of terpene pres- 

 ent. 



As before stated, many volatile oils 

 contain, besides the terpenes, an oxygen- 

 ated or odorous constituent, which is 

 often deposited as a crystalline mass on 

 exposure to cold, or is separated by frac- 

 tional distillation. This class of bodies 

 were named by Berzelius as stearoptenes, 

 by Nauman as camphors. These stear- 

 optenes are characterized by high den- 

 sity, higher boiling point, ready solubil- 

 ity in weaker alcoholic liquids. We find 

 among them alcohols, phenols, ketones, 

 aldehydes, etc. 



For example, the stearoptenes of the 

 oils of caraway and dill is carvol, a ke- 

 tone ; cinnamon is cinnamic aldehyde ; 

 lemon is citrol, an aldehyde ; anise is 

 anethol, a phenol derivative ; peppermint 

 is menthol, an alcohol; thyme is thymol, 

 a phenol ; coriander and angelica contain 

 a mixture of compounds. It is evident 

 that where the odor of an oil resides in 

 this oxygenated portion which is not sub- 

 ject to change or resinification and is also 

 soluble in diluted alcohol, it when sepa- 

 rated, would afford a valuable substitute 

 for the oil itself, 



These facts were first utilized and de- 

 veloped through the effoits of Heinrich 

 Haensel, of Piria, in 1876, when he 

 demonstrated that carvol is the only 

 valuable constituent in oil of caraway, 

 placing the " Patent Oil of Carawaj^ " on 

 the market, This was soon followed by 

 the "concentrated" oils of clove, pep- 

 permint, lavender, bergamot, lemon, or- 

 ange and others. The true value of 

 these discoveries was not recognized until 

 Professor Geissler in 188 1 and Professor 

 Fliickiger in 1883 published the results 

 of their investigations of the active con- 

 stituents of the oils of lemon, orange and 

 angelica. Geissler described the ter- 

 peneJess oil of lemon, stating that it far 

 exceeds the commercial oil in strength of 

 odor and flavor, stability, .solubility and 



strength, it being an oxygenated liquid, 

 like all others of this class, of constant 

 boiling point, composition and specific 

 gravity ; the commercial oil of lemon 

 having the specific gravity of 0.860, the 

 terpene citrene 0.850, while the terpene- 

 less oxygenated portion has the gravity 

 of 0.900. 



The insolubility of the volatile oils is 

 often the source of annoyance and loss, 

 since in the preparation of the aromatic 

 extract the addition of oils renders the 

 solutions turbid with the separation of a 

 portion of the oil, renders subsequent 

 clarification necessary, which entails a 

 loss of material and time. The presence 

 of these terpenes gives rise to other diffi- 

 culties, besides hindering the solubility, 

 and that is their use in essences, confec- 

 tions, etc. Although the oil employed may 

 be fresh and sweet, the articles flavored 

 will on standing gradually develop a tere- 

 binthinate odor and taste, due to the 

 oxydation of the terpenes in the oil. 

 Thus we see that the presence of these 

 terpenes in many oils simply cover the 

 true flavor,- and are a constant source of 

 menace to their quality. 



As will be seen from the list below, 

 the strength of such a concentrated oil 

 must vary, according to the comparative 

 amount of terpenes contained in the 

 crude oil ; the smaller the amount of the 

 oxygenated constituent after the removal 

 of the terpenes the more concentrated is 

 the product. We find them varying 

 from twice to thirty times the strength 

 of the natural oil. The value of these 

 products may be summed up as follows : 

 Great concentration, easy solubility and 

 freedom from the terebinthinate odor or 

 flavor. These points adapt them special- 

 ly in the manufacture of liquors, essences, 

 perfumes, confections, etc. 



Comparative strength 

 to other oils. 



Terpeiieless Oils of Angelica, Lemon, Or- 

 ange - -30X 



Terpeneless Oil of Juniper Berries . 20 x 



" Calamus — _ 8x 



" " Wormwood lox 



" " Coriander Seed 6x 



" Thyme 5x 



Oils of Cumin, Laurel, Mace, 

 Rosemary _ 4X 



Terpeneless Oils of Anise, Bergamot, Cara- 

 way, Cassia, Clove, Fennel, Lavender, 

 I/Cmon-grass, Peppermint, Pimenta, Sas- 

 safras 2 to 2^ x 



