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XXXI. On the Hydrate of the Oil of Laurel Turpentine. 

 ^3/ John Stenhouse, P/f.Z).* 



A FORMER communication contained a short account of 

 -^^ a volatile oil called laurel oil of Guiana, said by Pro- 

 fessor Christison to be obtained by incisions from a species of 

 ocotea. It was found to consist of two isomeric oils, having 

 the same composition, Cg H4, as oil of turpentinef. 



A quantity of this oil was mixed with some spirits of wine 

 and a little nitric acid, exactly in the way recommended by 

 M. Wiggers for procuring the hydrate of oil of turpentine. 

 After it had stood for some months, a large portion of the 

 oil was converted into a crystalline mass of a deep yellow 

 coloui'. By dissolving it and repeatedly crystallizing it out of 

 spirits of wine, it was readily procured in fine large rhombic 

 prisms, which were perfectly white, and had neither taste or 

 smell. These crystals melted at 257° F., and when heated 

 began to sublime at about 266'' F. When dried at 212° F. 

 they were subjected to analysis in the usual way. 



I. 0*2615 grm. substance gave 0*662 of carbonic acid and 

 0*275 water. 



II. 0*3068 grm. gave 0*780 of carbonic acid and 0*321 water. 



Calculated numbers. 



It is evident from these analyses that the crystals of hydrated 

 laurel oil are isomeric and isomorphous with those of the hy- 

 drates of the oils of turpentine and cedar. Their most probable 

 formula is Cg H4+ HO, or one atom oil and one atom water. 

 This is rendered still more probable by the following experi- 

 ment. When a portion of these crystals were distilled with 

 anhydrous phosphoric acid they yielded a colourless oil, 

 lighter than water, which had the same taste and smell as 

 laurel oil, and appeared to be that oil regenerated. Unfor- 

 tunately, from the small quantity of the crystals in my pos- 

 session, I was unable to verify this by analysis. 



The crystals also dissolved when gently heated in strong 

 sulphuric acid, to which they gave a red colour. They 

 evolved balsamic vapours which strongly reddened litmus. 

 The addition of water precipitated the oil changed into a 

 tenacious resin. 



* Communicated by the Chemical Society; having been read April 1, 

 1844. 

 t See Phil. Mag. S. 3. vol. xx. p. 273. 



