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OBSERVATIONS ON COPAIBA. 
According to Guibourt, copaiba yields 45 volatile oil, and 
the resinous residue consists of 98 parts of copaivic acid and 
2 parts soft resin. 
Mr. Whipple (Pereira) obtained 48 per cent of resin and 
52 per cent of volatile oil. 
In addition to the above I have examined five specimens 
of copaiba obtained at different times in the Philadelphia 
market, and also a sample of oil of copaiba which had been 
kept long in a bottle imperfectly stopped until it became 
slightly resinous and more viscid than copaiba itself. As a 
means of distinguishing them I will attach the letters of the 
alphabet. The method adopted to ascertain the amount of 
oil and resin was to place a weighed quantity, say 100 
grains, of the specimen in a small weighed capsule and ex- 
pose it to a regular heat at about 250° F. until the oil was 
evaporated and it ceased to lose weight. The capsule was 
then weighed and the loss ascertained. Although this 
method of analysis is not so accurate as distillation with 
water, using a larger quantity, and weighing the distilled oil 
and the residue resin»separately, yet it is sufficiently precise 
to answer the object ''of 'the writer. 
(a.) This specirAerl was remarkable for being very 
slightly resinous. Its specific gravity was only .916; its odor 
purely that of copaiba ; it was light straw colored, very 
fluid, and consisted of SO parts of volatile oil, and 20 parts 
of resin. The latter was soft, adhered to the fingers, and 
was slightly acid 'to litmus when dissolved in alcohol. The 
origin of this specimen is uncertain, but it is believed to be 
from Para. Sixty grains of it was heated several minutes 
with one-sixteenth of recently calcined magnesia, and set 
aside twenty-four hours. No combination ensued : the 
magnesia settled to the bottom, the copaiba remaining 
transparent above it. 
(b.) Origin unknown, consistence rather thin, odor good 
color brownish yellow, and sp. grav. .956. It consisted of 
65 parts volatile oil, and 35 of resin ; when heated 
