BENZOIN. 235 
tion of impurities is larger, sometimes very large. The odour of 
Sumatra benzoin is weaker and less agreeable than that of the 
Siam variety. The Sumatra benzoin is inferior in appearance to 
the Siam and is not generally so pure, hence its marketable price 
is lower. The greyish-brown part melts at 95° C., and the tears 
at 85° C. | 
As before observed, the Penang benzoin is markedly different in 
odour to that of Siam or Sumatra. 
Another description of benzoin is yielded by the Terminalia 
angustifolia, Jacq. * ; syn. T. Benzoin, Linn. t ; Catappa Benzoin, 
Gertner {. This is a tree of 30 or 40 feet in height ; a native of 
the East Indies. The gum is procured by wounding the tree ; it is 
composed of large white and light brown pieces, breaking very easily 
between the hands. It contains benzoic acid. When gently dried 
it forms a white powder, formerly in great request as a cosmetic, 
its perfume being very agreeable. 
Benzoic acid has a sharp acid taste and produces a peculiar 
irritation in the throat. It melts at 121°-4 and boils at 249°, but 
volatilizes at 100°, and sublimes rapidly at 140°. It also volatilizes 
with steam, one gramme passing over with two litres of water. 
_Its vapour has an aromatic penetrating odour, produces coughing 
and attacks the eyes violently, more mildly when it is mixed with 
steam. 
Benzoic acid crystallizes in lustrous, flat, monoclinic plates or 
needles ; by the gradual evaporation of its solution it is obtained 
in larger tablets, which, however, are always thin. 
1000 parts of water dissolve 
at 
10° 20° 30° 40° 50° 60° 70° 80° 90° 100° 
210; (52:90 4:10 — 5:55 7°75. 5b A775 «27-15 «~40°75 58-75 
parts of this acid §. 
100 parts of absolute ether at 15° dissolve 31°35 parts ; 100 
parts of 40°/o alcohol 41°62 parts ; and 100 parts of absolute 
alcohol, 46°48 parts of benzoic acid ||. It also readily dissolves 
* Hort. Vind. iii. t. 100. 
+ Sup. Lam. Dict. i. p. 349. 
} Fruct. ii. p. 206, t. 127. 
§ Ann. Chim. Phys. [5] xv. p. 168. 
| Bull. Soc. Chim. xxix. p. 242. 
