900 ESSENTIAL OILS. 



4 volumes (Delalande.) Camphogen exists in some essential oils, 

 which are mixtures of a liquid hydrocarbon and an oxidated oil, 

 as the essence of cummin. Camphogen in its chemical relations 

 resembles benzin or benzole and napthaline. 



Hyposulpho-camphic acid, HO + C 10 H 13 , S 2 O 5 ; is formed 

 when camphogen is heated on a water-bath with a slight excess 

 of fuming sulphuric acid ; the camphogen disappears without any 

 evolution of sulphurous acid, and an acid is produced analogous 

 to hyposulphobenzic acid, which forms a soluble salt with lead. 

 Hyposulpho-camphate of lead crystallizes in pearly plates, which 

 contain 4 atoms of water of crystallization, PbO + C 20 H 13 ,S 2 O 5 

 + 4HO ; but are made anhydrous by a temperature of 248. The 

 salt of barytes is similar in constitution. This salt and the 

 salt of lime are remarkable for their taste, of which the first 

 impression is very disagreeably bitter, but changes in a minute 

 or two into a sweet and sugary taste analogous to that of 

 liquorice. 



Camphogen also forms a white crystallizable compound when 

 acted upon by fuming nitric acid. (Delalande, Ann. de Chim. 

 3 ser. i, 368). 



Camphoric acid, 3 HO 4 3C 10 H 7 O 3 . This acid, which is tri- 

 basic, is produced by long digestion or repeated distillation of 

 camphor with nitric acid ; and is divested of adhering camphor 

 by uniting it with potash, and decomposing the salt by nitric 

 acid. It forms prismatic crystals, which are inodorous, of a 

 very sour taste; fuses at 145.4 (63 centig.), and emits then a 

 pungent vapour. It sublimes partially as the anhydrous acid. 

 It is indifferently soluble in water, more readily dissolved by 

 alcohol. 



Camphoric acid forms a neutral and acid salt with ammonia:, 

 the former contains 3 atoms of oxide of ammonium, and the 

 latter 2 atoms of the same with 1 atom of water as base. 



Acid camphorate of oxide of ethyl is formed when camphoric 

 acid, alcohol and sulphuric acid are heated together ; and is 

 separated by the addition of water. It appears to contain a 

 bibasic camphoric acid, of which the formula is C 20 H 14 O 6 , united 

 with 1 atom of oxide of ethyl and 1 atom of water. The atom of 

 water can be replaced by fixed bases, and a class of neutral salts 

 formed. By boiling the acid camphorate of oxide of ethyl with 



