BENZOIC ACID. 849 



water are resolved into 1 atom of ammonia and 1 atom of anhy- 

 drous amygdalic acid : 



C 40 H 27 NO 22 and 2 HO^C^H^O^ and NH 3 . 



Amygdalic acid is obtained by evaporation as a transparent 

 colourless amorphous mass ; it has a very agreeable acid taste, 

 is insoluble in alcohol and ether, but so soluble in water as to 

 deliquesce in damp air. 



Nitric acid and the mixture of peroxide of manganese and 

 dilute sulphuric acid act on amygdalic acid as on amygdalin, 

 allowing for the absence of nitrogen from the former, the pro- 

 ducts being volatile oil of bitter almonds, formic and carbonic 

 acids, all of which are disengaged in the state of gas. 



Little is known of the amygdalates ; they appear to be in 

 general soluble salts, with the exception of a basic salt of lead. 

 Amygdalin, it will be observed, has the composition of amyg- 

 dalate of oxide of ammonium, from which the elements of 3 

 atoms of water have been abstracted ; or it has lost 1 atom of 

 water more than a true amygdalamide (Liebig). 



SECTION II. 

 BENZOYL SERIES OF COMPOUNDS. 



Benzoyl or benzo'ile,* C 14 H 5 O 2 =Bz. This is the hypothetical 

 radical of a series of compounds, including benzoic acid, (from 

 which it derives its name), and the essence or volatile oil of 

 bitter almonds. The last substance is derived from amygdalin 

 by various means. Amygdalin exists also in the kernels of many 

 fruits, and in the leaves of the laurel. 



BENZOIC ACID. 



Formula: HO,C H H 5 O 3 = HO, BzO. This acid exists 

 ready formed in several resins, particularly benzoin and dragon's 

 blood. It is produced by the decomposition of amygdalin by 

 oxidating matters, by the oxidation of essence of bitter almonds, 

 of hippuric acid, and in many other circumstances. 



* Benzulf of several English chemical writers. 



2 K K 



