90 DIPTEROCARPE^. 



parts of absolute alcohol yielded on cooling a precipitate of resin 

 amounting when dried to 18'5 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 resm, 

 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 ceni 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 0-915 ;i 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 



n 



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

 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 



proportion of a 



after this treatment deviates the ray to the rio-ht 



The resin contains, like that of copaiba^a small 

 crysta lizable acid which may be removed by warming it wi'th ammonia 

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

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

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



covrect 





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

 g the resm with alcohol (-838) and mixin- the solution with ammonia. 



J^rom the aramoniacal solution gurjunic acid is precipitated on addition 

 ox a naineral 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. 



conS^'^""'' ^''^' ?'^''^' according to Werner, melts at 220° C aud 

 tiinHr ^^"-"X-^ ^^^ ^■' '^ ^^gi"« t« ^0^1 at 260" C, yet at the san 



C-H-STJS^;^"^^^^ Pl^ce. By assigning to this acid the fomiul 

 ^ w *-* +^H20, which agrees well with Werner's analytical results, ^^e 



o4£gt.::VtoVDoV^^^^^^^^^^ /Tbe sample of gurjun balsam exam;; j 



=» This magiiifi..f.nf .!;i ^ ^^^^^- ^y Werner aa well as tlie resm it cf^r^j^e. 



not dissolv^^bv eSer "''^ '"""^^ ^^ ^' ^« '^"^"•^ soluble in boiling potash lye 



3 P/iam. Journ. xvi. (1857) 374. ' Gmelin, Chemhtry, xvu. 64a. 



