232 VEGETABLE SUBSTANCES. 



CHAPTER XIII. 



ESSENTIAL OILS. 

 HUILE ANTIQUE LAVENDER. 



EMPYREUMATIC OILS. 

 BIRCH TAR PITCH. 



WHILE the grosser oils are extracted from the fruit 

 and seed, essential oils are mostly obtained from the 

 leaves and flowers or from the most odorant part of 

 plants. In umbelliferous plants the oil is, however, 

 found in the seeds. In the gciuji, or averts, the root 

 affords it, and in labiated plants it is contained in 

 the branches and leaves. The essential oils obtained 

 from flowers are in general of a very delicate na- 

 ture ; and the odorous matter of some flowers is 

 so subtile that it can only be obtained by impreg- 

 nating another substance with it ; in any attempts to 

 secure it as an essence it diffuses itself, and will not 

 be confined. Of this description of flowers are tube- 

 roses, jasmine, honey-suckle, sweet-briar, and others 

 of the same delicate nature, having strong scents, but 

 which yield little or no oil by distillation. 



Ben oil, as being perfectly inodorous and not liable 

 to rancidity, is an excellent agent for retaining and 

 imparting the perfume of the sweet-smelling flowers. 

 L'huile antique, so designated as being produced by 

 the method in which the ancients prepared their 

 scented oil, is ben oil impregnated with the odorous 

 matter of flowers. Cotton soaked in the oil is placed 

 in alternate layers with the flowers whose scent is to 

 be obtained ; a close tin or pewter vessel is used for 

 this purpose, which when thus filled has its cover 



