BY J. H. MAIDEN. 437 



This interesting resin has formed the subject of chemical 

 researches for nearly one hundred years. Following are abstracts 

 from some of them, — none of them recent. A modern research 

 is a desideratum. 



" Of a darker reddish-yellow than gamboge, frequently covered 

 with a greenish-grey crust. Brittle, of shining fracture, triturable 

 to a greenish-yellow powder. Does not stick to the teeth. Tastes 

 sour and aromatic, and has an agreeaVjle balsamic odour. Contains 

 a very small quantity of an agreeably-smelling volatile oil; a resin 

 soluble in alcohol and ether, and also in alkalis and baryta- and 

 lime-water ; a little benzoic acid and bassorin (Laugier, Ann. 

 Chim., 76, 265). Its solution in ether or alcohol leaves on evapora- 

 tion a dark resin, containing, at 12U°, 66'98 p.c. C, 5"73 H, 

 27 '29 O, corresponding to the formula C40 H^q O^o and almost 

 entirely precipitable from its alcoholic solution by water, even in 

 the presence of a large quantity of ammonia." (Johnston, Phil. 

 Trans. 1839, 292.) 



" The resin gives up to boiling water benzoic acid and gum. It 

 dissolves in oil of vitriol, forming a pale browii solution, which is 

 precipitated of a violet-red by water. It colours acetic acid yellow, 

 without dissolving in it to any great extent and dissolves easily in 

 alcohol, ether, some volatile oils, and partially in fatty oils, form- 

 ing in all cases tine yellow solutions " (Widmann; Lichtenstein ) 

 [Gmelin's Handbook, xvii., 386-7]. 



" Colour deep yellow, with a slightly reddish shade, considerably 

 resembling gamboge, but darker and less pleasing. The colour of 

 its powder is greenish-yellow. When gently heated it melts, and 

 when strongly heated it burns with a strong smoky flame, and 

 emits a fragrant odour resembling balsam of tolu. The resin 

 contains a trace of an essential oil, to which much of its agreeable 

 smell is owing. This oil passes into the receiver when the resin is 

 distilled with a mixture of carbonate of soda and water, but its 

 quantity is so small that I was unable to examine it more closely. 

 The resin is insoluble in water, but dissolves readily both in 

 alcohol and in ether, especially in the former. Its solution in 



