134 ODOEOGRAPHIA. 



crude oil with an alcoholic solution of sulphide of ammonium; 

 sulphydrate of car vol 7S then formed, and this compound, 

 decomposed by ammonia, yields car vol.* 



The sp. gr. of carvol is 0-963 at 15° C, and its boiling point 

 227° C, but the temperature gradually rises owing to partial 

 decomposition caused by heat. 



Carvene boils at 173° C, is colourless, mobile and lighter than 

 water. It has the property of absorbing hydrochloric acid gas 

 forming a pure white crystalline compound which melts at 50'5° C, 

 but re-solidifies only at 41° C.f (This may be an error as regards 

 point of solidification, see Anise oil). 



This bi-chlorhydrate, C^^ H^g 2 H CI. is very soluble in water, 

 but its solution is decomposed by heat. It is also decomposed by 

 sublimation. 



Carveol or Carvyl alcoJiol is formed by the action of sodium on 

 an alcoholic solution of carvol ; it is a viscous liquid, differing in 

 odour from carvol. 



Carvene is obtained in large quantities as a by-product in the 

 separation of Carvol from oil of caraway. It is not suitable 

 for perfumes or liqueurs as it is insoluble and does not possess 

 that delicate odour and taste peculiar to carvol, but it can be 

 satisfactorily employed instead of caraway oil in perfuming soaps 

 of medium and cheap quality. 



The value of oil of caraway depends on the percentage of carvol 

 contained in it. Messrs. Schimmel & Co. state that the products 

 brought into commerce under the name " Carvol " are frequently 

 caraway oil from which a portion of the carvene has been removed 

 by fractional distillation. As a means of determining the purity 

 of carvol, they indicate its solubility in 50 per cent, alcohol as 

 follows : — Pure carvol dissolves at 20° C. in the proportion of 1 

 part by weight in 16 to 17 parts by weight of 50 per cent, alcohol. 

 A sample of carvol to which 2 percent, of carvene had been added, 

 did not dissolve clear in 20 parts of 50 per cent, alcohol at 20° C. 

 It is of importance to use alcohol of exactly this strength for the 

 test, or at any rate not stronger, because with a higher concentra- 



* Sulphydrate of carvol crystalUses from solution in alcohol in long needles 

 having the lustre of satin ; these are fusible, and when cautiously heated, 

 sublime almost unaltered. 



t Schweizer, Journ. f. Prakt. Chem., xxiv., p. 257. 



