JSS TESTS OF THE PURITY OF BALSAM OF COPAIBA. 
simple test, has hitherto been pointed out. Some of the 
tests, which appear to have been most relied upon, I believe 
to be quite valueless, and I have no doubt that many sam- 
ples of copaiba have been condemned as impure on very- 
insufficient data. 
In obtaining the results which I am about to describe, I 
have used the following specimens of copaiba, but some of 
the experiments were repeated on several others : 
1. Part of a specimen in our Museum, which was re- 
ceived about two years ago from one of our members, Mr. 
Goodbarn at Rio de Janeiro. It was taken by Mr. Good- 
barn himself, from a tree in a primeval forest, in the district 
of Macahe, about four day's journey from the city of Rio de 
Janeiro, on the 5th of July, 1S43. The tree was at the 
same time cut down, and some of the wood, bark, and 
leaves were sent with the specimen. On comparing these 
with Hayne's plates, they were found to correspond with 
those of Copaifera trapezifolia. Mr. Goodbarn described 
the tree as having been one hundred feet in height, and 
about three and a half feet in diameter. This is probably 
one of the best authenticated specimens of genuine copaiba 
in this country. 
2. A specimen of copaiba taken from some capsules, said 
to have been imported from France. This specimen was 
brought me for examination by a merchant in the city. It 
had been previously examined and condemned as impure, 
but I believe it to be genuine and very good. 
3. A specimen of good commercial copaiba obtained from 
a wholesale house. 
The following are the tests which I have applied to these 
specimens, together with the results : 
t/£. The addition of two parts of absolute alcohol to one 
of copaiba has been recommended as a means of ascertain- 
ing whether any substance insoluble in alcohol has been 
mixed with the copaiba. This is one of the tests given in 
