SUBSTANCE IN BALSAM pF MECCA. 383 



IX. 



Chemical Examination of a Substance found in Balsam of 

 Mecca: by Mr. Vauquelin*. 



.R. HALLE, a member of the Institute, &c, requested Portion «f bai- 

 rn c to examine a substance, which he obtained from balsam no . t3 \^ en up 

 of Mecca on dissolving it in alcohol by means of heat. This by alcohol, 

 substance had the appearance of a resin, was transparent, 

 and had an agreeable smell. Thrown on burning coals, it 

 emitted a smoke and smell like those of frankincense, and 

 left no coally residuum. 



I took a gramme [15| grs.] of it, and treated it with al- Boiled jHJJJj 

 cohol at 40°. The first effect of this was to render it opake 

 from the surface to the centre, as soon as it began to exert 

 its action, and it soon gave it a flocculent form throughout. 

 I continued to boil fresh quantities of alcohol on this floc- 

 culent substance, till it no longer rendered distilled water 

 turbid. 



The insoluble flocculent matter, being collected, weighed ■} insoluble. 

 0-3 of a gramme, or nearly a third of the substance mi. 

 ployed. Heat united it into masses of great tenacity, which 

 drew out into threads like birdlime, without however pos- 

 sessing any elasticity. Thrown on burning coals it emitted 

 the same smell of frankincense as before, and left no re- 

 siduum. 



The alcoholic solution was transparent while hot; but on The solution 

 cooling grew turbid, though it let fall no sediment. During 

 evaporation a white flocculent matter appeared, in propor- 

 tion as the alcohol was diminished; and when completely 

 dried part remained in a pulverulent and spongy form. 

 Another portion united into a transparent mass, having 

 nearly the appearance of turpentine, lioth of these burned 

 like resins, but with a less agreeable smell than the part in- 

 soluble in alcohol. 



These experiments prove, that in the residuum of balsam of It consists 

 Mecca insoluble in cold alcohol, put into my hands by substan^a W ° 

 Mr. Halle, there are two substances ; one, which dissolves 

 in a very large quantity of boiling alcohol; and another, 



* Annales de Chimie, vol. lxix, p. 221. 



which 



