BALSAM. 
Liquid balsams. The liquid balsams at 
present known are five in number ; namely, 
1. Opobalsamum. 4. Peru. 
2. Copaiva. 5. Styrax. 
3. Tolu. 
1. Opobalsamum, or balm of Gilead. — 
This balsam is obtained from the amyris 
Gileadensis, a tree which grows in Arabia, 
especially near Mecca. It is so much va- 
lued by the Turks, that it is seldom or 
never imported into Europe. We are, of 
course, ignorant of its composition. It is 
said to be at first turbid and white, and of 
a strong aromatic smell, and bitter, acrid, 
astringent taste; but by keeping, it be- 
comes limpid and thin, and its colour 
changes first to green, then to yellow, and 
at last it assumes the colour of honey, and 
the consistence of turpentine. It is also 
very tenacious and glutinous, sticldng to the 
fingers, and may be drawn into long threads. 
The mode of ascertaining the purity of this 
balsam at Cairo and Mecca is to drop it 
into a cup of clear cold water; if it re- 
main in one place on the surface, it is of 
little or no value, but if it extend itself 
like a skin over the whole surface, (and this 
skin is even and almost transparent, and 
may be taken off the water with a hair,) it 
is of great worth. The balsam of Gilead 
principally comes from Arabia Petrasa, from 
whence the Arabs carry it to Mecca for 
sale, during the stay of the caravans from 
Egypt and Turkey. It grows also in the 
Holy Land, but not without much culture 
and attention, whereas in Arabia it grows 
without cultivation. It is the produce of 
a species of the amyris, rising to the height 
of the pomegranate tree, to which it has a 
great resemblance, both in its branches and 
fiowers. See Amyris. The balsam is ob- 
tained by incision during the summer 
months, flowing over in a viscous juice, 
called Opobalsamum. It is white when it 
comes from the tree, and changes first to a 
green, and afterwards to a gold colour. 
2. Copaiva. — This balsam is obtained 
from the Copaifera officinalis ; a tree which 
grows in South America, and some of the 
West Indian islands. It exudes from in- 
cisions made in the trunk of the tree. The 
juice thus obtained is transparent, of a yel- 
lowish colour, an agreeable smell, a pun- 
gent taste, at first of the consistence of oil, 
but it gradually becomes as thick as honey. 
Its specific gravity is 0.950. When mixed 
with water and distilled, there comes over 
with the water a very large portion of vo- 
latile oil. The oil ceases to come over be- 
fore all the water has passed into the re- 
ceiver. The residuum, of course, consists 
of two substances ; namely, the watery 
portion, and a greyish yellow substance, 
lying at the bottom of the vessel, which, 
on exposure to the air, dries, and becomes 
brittle and transparent. When heated, it 
melts, and possesses the characters of a 
resin. Nitric acid acts upon this balsam 
with considerable energy. When one part 
of the balsam is mixed with four parts of 
nitric acid and two parts of water, and 
heated, a yellowish solution is formed, similar 
to the original balsam, but darker. When 
distilled, there comes over with the liquid 
that passes into the receiver an apple -green 
oil, which lines the helm of the retort. The 
nature of the residue was not examined. 
When treated with sulphuric acid, it yields 
a portion of artificial tannin. Whether this 
balsam yields benzoic acid has not been as- 
certained. Its properties are rather against 
the probability of its doing so. Indeed it 
bears a striking resemblance to turpentine 
in many respects ; and ought, along with it, 
to constitute a class of bodies interme- 
diate between volatile oils and resins, to 
which the name of turpentines might be 
given. 
3. Balsam of Tolu. — This substance is 
obtained from the Toluifera balsamum, a 
tree which grows in South America. The 
balsam flows from incisions made in the 
bark. It comes to Europe in small gourd 
shells. It is of a reddish brown colour and 
considerable consistence, and when ex- 
posed to the air it becomes solid and brittle. 
Its smell is fragrant, and continues so even 
after the balsam has become thick by age. 
When distilled with water, it yields very 
little volatile oil, but impregnates the water 
strongly with its taste and smell. A quan- 
tity of benzoic acid sublimes, if the distil- 
lation be continued. Mr. Hatchett found 
it soluble in the alkalies, like the rest of the 
balsams. When he dissolved it in , the 
smallest possible quantity of lixivium of 
potash, it completely loses its own odour, 
and assumes a most fragrant smell, some- 
what resembling that of the clove pink. 
“ This smell,” Mr. Hatchett observes, “ is 
not fugitive, for it is still retained by a so- 
lution which was prepared in June, and has 
remained in an open glass during four 
months." When digested in sulphuric acid, 
a considerable quantity of pure benzoic acid 
sublimes. When the solution of it in this 
acid is evaporated to dryness, and the resi- 
