ESSENTIAL OILS. 379 

 ESSENTIAL OILS. 

 What is said ^50. V LATIL E, OR ESSENTIAL OILS. 



of the compa- Oils of turpentine and lemon, and otto of 



rative compo- 

 sition of es- roses, are examples of essential oils. They 

 sential oils ? are a i most as var i ous as plants themselves. 



Yet the composition of those that differ most widely 

 is often the same. This is the case with the oils of 

 orange, lemon, pepper, turpentine, juniper, parsley, 

 citron and bergamot. They contain carbon and hy- 

 drogen alone, and in the same proportion; twenty 

 atoms of the former to eight of the latter. Those of 

 bitter almonds, cinnamon, cloves, and anise-seed, con- 

 tain oxygen beside. Those of mustard, and onions, 

 contain oxygen, and sulphur, in addition, and are char- 

 acterized, like all sulphuretted oils, by a peculiar, pun- 

 gent smell, and acrid, burning taste. 



951. OCCURRENCE AND PREPARATION. 



How are the . 



essential oils Essentials oils are oftenest found in the 

 prepared? fl owe rs, seeds, and fruits of plants, but 

 sometimes in the stalks and roots. From these they 

 are obtained by distillation with water. The volatile 

 oil passes over with the steam, and floats upon the con- 

 densed liquid in the receiver. Oil of turpentine is thus 

 made, from the common turpentine, or pitch as it is 

 sometimes called, which exudes from the pine ; ordi- 

 nary rosin remains behind. The delicate perfume of 

 violets, and other flowers which contain but a small 

 portion of essential oil, is extracted by mingling the 

 flowers with lard. This substance has the property of 

 absorbing the oil, and yielding it again by distillation. 



