S14 



ANALYSIS OF THE YELLOW GL'M. 



tsiitii! with 

 water 



yielded a hot 

 and fEograni 

 oil. 



Thk. oil ob- 

 tained from 

 the tincture. 



The resin 

 forms a soap 

 ^'th alkalis or 

 lime. 



T!"p benzoic 

 acjtl not ob- 

 lairidble from 

 this. 



which it collapses, nnd diminishes in bulk. In tliis state it 

 is ot' a deep brown colour, which appears purplish when 

 placed between the eye and the light. 



The alcoholic solution also yields a few crystals of benzoic 

 acid by distillation to dryness, though not so easily. The 

 alcoliol distilled from it reddens litmus paper, which shows, 

 that it probably carries oft' a portion of the same acid. 



1 introduced 30 gi'aius of the yellow resin into a retort 

 with four ounces of distilled water, fitttd to it a receiver, 

 arid distilled on a sand-heat. The water, that passed into 

 the receiver, was turbid, on account of the suspension of a 

 certain quantity of essential oil, several drops of which col- 

 lected on the surface. The water thus mixed with oil had 

 au extremely pleasant smell. The extremity of the beak of 

 the retort was soiled with this oil, vi^hich had an acrid and 

 burning taste nearly like that of the oil of cloves. When 

 the matter remaining in the retort was dry, white fumes 

 arose, that condensed in the head of the retort in small 

 and very white crystals, which powerfully reddened litmus 

 paper, and had the strong and pleasant smell of benzoic 

 acid. 



The essential oil of the yellow resin may be obtained also 

 by distilling the alcoholic solution : the alcohol, that passes 

 over into the receiver, being insensibly impregnated with it; 

 so that the evaporation of this liquid by a gentle heat is suf- 

 ficient to procure this acrid and pleasant substance. 



Caustic alkalis, or lime, placed in contact with the yellow 

 resin, immediately assume a deep yellow colour, without 

 the assistance of heat ; and dissolve the resin completely, 

 if they be employed in sufficient quantity. The solution 

 froths when shaken, like that of soap, and lets fall a yel- 

 lowish white precipitate on the addition of an acid. 



I had hoped, that this solvent action of the alkalis would 

 furnish me with an easy mode of separating the benzoic 

 acid from the resin ; but several trials convinced me of the 

 impossibility of succeeding. It appears, that this acid falls 

 down at the same time as the resin, the moment another 

 acid is added to the mixture. 



Thirty grains of the yellow resin in powder being heated 

 in a retort with six times the weight of nitric acid, a consi- 

 derable 



