150 
STYRAX BENZOIN. 
when the trunk acquires about seven or eight inches in diameter,) 
begins to afford the benzoin j the bark is then cut through longitu- 
dinally, or somewhat obliquely, at the origin of the principal lower 
branches, from which the balsam exudes in a liquid state, which by 
exposure to the sun and air soon concretes, and when sufficiently 
hard it is scraped from off the bark with a knife or other instrument. 
These incisions are annually repeated for ten or twelve years, after 
which period the tree becomes nearly exhausted, and the balsam 
which it affords less pure. The benzoin which issues first from the 
wounded bark is the purest, being soft, white, and extremely fragrant ; 
that which is of a brownish colour and very hard, is less esteemed. 
The benzoin of commerce is distinguished into different kinds ac- 
cording to their purity, the purest of which is denominated white 
benjamin, and the most impure and dark coloured, black benjamin. 
The benzoin of the shops is ir^, large brittle masses, composed of 
variously coloured pieces, and that which contains most white and 
light coloured masses is accounted the best. 
Sensible and Chemical Qualities, &c. Gum Benjamin* 
has a very fragrant and pleasant odour, but scarcely any taste ; 
when chewed it breaks down in the mouth, tasting resinous, and 
rather sweet ; it does not adhere to the fingers j when heated it soon 
melts, froths, and gives out a balsamic, pleasant fume, which catches 
fire from a candle, and burns with a vivid, smoking flame, leaving a 
brittle, shining charcoal. 
Distilled by itself it yields about 9 per cent, of crystallized ben- 
zoic acid, which, when procured in this manner, is called flowers of 
benjamin ; 5.5 of acidulous phlegm ; 60 of a butter-like burnt oil 3 
22 of charcoal, and 3.5 of carburetted hydrogen gas, mixed with 
carbonic acid gas.f Water extracts part of its benzoic acid, if dis- 
tilled together no essential oil comes over. Spirit of wine dissolves 
it ; the tincture is rendered turbid and white by water ; it also 
readily dissolves in zether. 
The benzoic acid is also separated by grinding sixteen ounces 
of gum benjamin with four of lime ; then boiling the mixture, first 
in a gallon of water, and then in half a gallon ; mixing the strained 
liquors, evaporating to one half, and dropping in about four ounces 
of spirit of salt, until no more precipitate falls down ; the liquor 
being poured off, the precipitated benzoic acid is dried, and after- 
* More properly &en;aotn, the Sanskreet or classical Indian name being hanjuu 
+ According to Mr. Brande's analysis, Nicholson's Joarn. vol. x. p. 86. 
