142 ODOROGRAPHIA. 



gas at a red heat on oil of turpentine, an oil is produced having the 

 composition of cymene.* 



Oil of wormseed distilled with phosphoric anhydride and then 

 with potassium, yields an oil isomeric, if not identical with 

 cymene. 



Cymene is considered to be methyl-propyl-benzene, containing 

 a methyl and an iso-propyl group in the para-position in a benzene 

 nucleus, thus : — 



Cymene shows the ordinary behaviour of benzene hydrocarbons 

 towards nitric and sulphuric acids, yielding respectively nitro and 

 sulphonic acid derivatives. 



Cymene is not decomposed by caustic potash under any 

 conditions, but chlorine and bromine attack it without the 

 application of heat, producing chlorinated and brominated com- 

 pounds decomposable on distillation. Distillation with potassium 

 bichromate and sulphuric acid produce a violent reaction ; caustic 

 potash being inert to the oil distilled over. 



Cold concentrated sulphuric acid does not attack cymene, but 

 fuming sulphuric acid converts it into s^olphonic acid, wliich 

 crystallises from dilute sulphuric acid in tablets containing 2 

 molecules of water; this body, on fusion with caustic potash is 

 converted into carvacrol (previously referred to). 



Cuminol, the second named ingredient of Cumin oil, C\o H 2 0, 

 formerly called Hydride of Cumyl also Cumincddchydc, is a 

 colourless or slightly yellow liquid having a very powerful and 

 persistent odour of cumin and an acrid, burning taste. Its dextro- 

 rotatory powder is slightly weaker than that of cymene. It exhil^its 

 the chemical properties of an aldehyde, combining with alkaline 

 bisulphites, and is easily transformed by oxidising agents into 



* Deville, Ann. Chim. Phys. [2], Ixxv., p. 66. 



