C 89 3 
IV. Chemical Experiments on Guaiacum. By Mr . William 
Brande. Communicated by Charles Hatchett, Esq. F. R. S. 
Read December 19, 1805. 
Among the numerous substances which are comprehended 
under the name of resins, there is perhaps no one which 
possesses so many curious properties, as that now under 
consideration; and it is remarkable that no more attention 
has been paid to the subject, since many of the alterations 
which it undergoes when treated with different solvents, have 
been mentioned by various authors. 
§1. 
Guaiacum has a green hue externally ; is in some degree 
transparent ; and breaks with a vitreous fracture. 
When pulverised it is of a gray colour, but gradually be- 
comes greenish on exposure to air. 
It melts when heated, and diffuses at the same time a 
pungent aromatic odour. 
It has when in powder a pleasant balsamic smell, but 
scarcely any taste, although when swallowed it excites a very 
powerful burning sensation in the throat. 
Its specific gravity is 1.2289. 
MDCCCVI. 
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