892 ESSENTIAL OILS. 



343.4 (173 centig.). It has absolutely the same composition 

 in 100 parts as essence of turpentine, but only half the atomic 

 weight. It forms, with hydrochloric acid both a solid and liquid 

 compound, according to Blanchet and Sell. The composition 

 of both is expressed by C 10 H 8 ,HC1. The camphor and also the 

 liquid hydrochlorate of lemon oil are decomposed by means of 

 alkalies, and furnish two oils, which possess the same compo- 

 sition as the essence employed. Oil of oranges, from orange- 

 peel (Citrus aurantium) differs only in smell from oil of lemons. 

 Oil ofneroli, or of orange-flower is quite different, and is in great 

 part soluble in water. It appears to contain a stearopten, but 

 its composition is not exactly known. 



Oil of junipers. Obtained by the distillation of crushed juni- 

 per-berries with water. It is colourless, and possesses the 

 taste and odour of juniper; is composed of two oils of different 

 volatility, both of them containing carbon and hydrogen in the 

 same relation as all the oils of this class, namely C 5 H 4 . By 

 adding a little of this oil to brandy, gin or Hollands are 

 formed. 



Savin- oil. Derived from the berries of Juniperus sabina, 

 colourless, also represented by some multiple of C 5 H 4 . Both 

 of these oils are used as diuretics. 



Oil of copaiba, C 10 H 8 . The balsam of copahu or copaiva is 

 extracted in Brazils and the Antilles from several plants, of the 

 genus copaifera. It is obtained by incision, in the same way as 

 common turpentine, with which it has a great analogy ; and is a 

 clear-yellow, transparent, thick liquid, consisting of a resin and 

 volatile oil. 



The oil is colourless, thin, of an aromatic but disagreeable 

 odour, of density 0.878, and boiling point 473. Absolute 

 alcohol dissolves two-fifths of its weight of this oil, but twenty- 

 five parts of the spirits of wine of commerce, are required to 

 dissolve one part. It forms a crystallizable compound with 

 hydrochloric acid ; it is isomeric with oil of lemons, and has the 

 same mode of condensation. (Blanchet). 



Copahuvic acid, C 40 H 32 O 4 . This name is applied to the resin 

 of copaiva, which possesses, according to Rose, the same compo- 

 sition as colophony. To obtain it crystallized, M. Schweizer 

 dissolves 9 parts of the balsam in 2 parts of ammonia, and 

 leaves the mixture in a cool place. The crystals which form 



