394 ODOROGKAPHIA. 



Mesitylenic acid is only soluble to a very small extent in cold 

 water and with difficulty in boiling water, from which it 

 crystallises in Hue, small needles. It separates from alcohol, in 

 which it is very readily soluble, in large, well-developed, mono- 

 symmetric crystals, while if boiling water be added to the dilute 

 alcoholic solution until a permanent turbidity is produced, the acid 

 crystallises on cooling in broad plates and needles, which closely 

 resemble those of benzoic acid. It melts at 166^' according to 

 Fettig,* while Jacobsen gives 169° as the melting point, but 

 sublimes below this temperature. Its salts have been examined 

 by Fettig and by Fettig and Brlickner.f 



Ethyl mesitylenate, Cg H^ O2, Co H., is formed by the 

 action of hydrochloric acid on a solution of mesitylenic acid in 

 absolute alcohol, and is a liquid which has a peculiar but pleasant 

 smell considered to resemble that of attar of roses, boils at 241° 

 and solidifies to a crystalline mass below 0°. 



Other chemical products are reputed to possess the " odour of 

 rose " (1st Series, p. 49) but so far as is at present known, that 

 odour has not been matched by any combination or synthetical 

 product, or is it to be found in nature in any other flower or plant.J 

 Even in roses it is only developed in purity in the it. ccntifolia 

 and B. Damascena ; the perfume of other species and varieties 

 being very distinct and of a very complex nature. 



* Ber. Deutsche Cbem. Ges., xi., p. 2054. 



t Ann. Chem. Pliarm., cxli., p. 129, and cxlvii., p. 45; and Zeitsclir. [2], 

 v., p. 169. 



% The recent alleged discovery by Monnet and Barbier, of Rhodinol in 

 oil of pelargonium, is referred to in the next Section. 



