90 DIPTEROCARPE^. 



parts of absolute alcohol yielded on cooling a precipitate of resin 

 amounting when dried to IS'o parts. All concentrated solutions of the 

 balsam are precipitated by amylic alcohol. 



If the balsam is kept for a long time in a stoppered vessel at 100° 

 C. it simply becomes a little turbid; but about 130° C. it is transformed 

 into a jelly, and on cooling does not resume its former fluidity. Balsam 

 of copaiba heated in a closed glass tube to 220° C. does not at all lose 

 its fluidity, whereas Gurjun balsam becomes an almost solid mass. 



Chemical Composition — Of the balsam 6'99 grammes dissolved 

 in benzol and kept in a water bath until the residue ceased to lose 

 weight, yielded 3"80 grammes of a dry, transparent, semi-fluid resin, 

 corresponding to 54'44 per cent., and 45'56 of volatile matters expelled 

 by evaporation. But another sample afforded us much less residue. 

 By submitting larger quantities of the above balsam to the usual 

 process of distillation with water in a large copper still, 37 per cent, of 

 volatile oil were easily obtained. The water passing over at the same 

 time did not redden litmus paper. A dark, viscid, liquid resin remained 

 in the still. 



The essential oil is of a pale straw-colour and less odorous than most 

 other volatile oils. Treated with chloride of calcium and again distilled, 

 it begins to boil at 210° C. and passes over at 255° — 260° C, acquiring a 

 somewhat empyreumatic smell and light yellowish tint. The purified 

 oil has a sp. gr. of 09 15 ;^ it is but sparingly soluble in absolute alcohol 

 or glacial acetic acid, but mixes readily with amylic alcohol. 



According to Werner (1862) this oil has the composition C^°H^^ 

 like that of copaiba. He says it deviates the ray of polarized light to 

 the left, but that prepared by one of us deviated strongly to the right, 

 the residual resin dissolved in benzol being wholly inactive. The oil 

 does not form a crystalline compound with dry hydrochloric acid, which 

 colours it of a beautiful blue.^ De Vry* states that the essential oil 

 after this treatment deviates the ray to the right. 



The resin contains, like that of copaiba, a small proportion of a 

 crj'stallizable acid which may be removed by warming it with ammonia 

 in weak alcohol. That part of the resin which is insoluble even in absolute 

 alcohol,* we found to be uncrystallizable. The Gurgunic Acid, as the 

 crystallized resinous acid is called by Werner,^ but which it is more 

 correct to write Gurjunic, may consequently be prepared by extract- 

 ing the resin with alcohol ('838) and mixing the solution with ammonia. 

 From the ammoniacal solution gurjunic acid is precipitated on addition 

 of a mineral acid, and if it is again dissolved in ether and alcohol it 

 may be procured in the form of small crystalline crusts. From the 

 specimen under examination we were not successful in obtaining in- 

 dubitable crystals, 



Guijunic acid, C**H^^O^ according to Werner, melts at 220° C, and 

 concretes again at 180° C; it begins to boil at 260° C, yet at the same 

 time decomposition takes place. By assigning to this acid the formula 

 C**H^O^ + 3H20, which agrees well with Werner's analytical results, we 



1 0*944 according to Werner; 0'931 * xhe sample of gurjun balsam examined 

 O'Shaughnessy ; 0-928 De Vry (1857). by Werner as well as the resin it contained 



2 This magnificent colouring matter is were entirely soluble in boiling potash lye. 

 not dissolved bv ether. ^ Gmelin, Chemistry, xvii. 545, 



8 Pliarm. Journ. xvi, (1857) 374. 



