OF ARTS AND SCIENCES. 



351 



" Second, On dry distillation, it yields scbacic acid, among many 

 other products, 



" These properties being so characteristic and peculiar as they are, 

 we might expect to find them with other members of the series ; but 

 the sequel will show that such is the case only 'in part, 



" The oleic acid is very widely diffused, forming, as it does, a con- 

 stituent of all the more important animal fats, and of most of the veg- 

 etable fatty oils. In a few cases only is it replaced by other acids 

 constituted according to the same general formula. 



" The doglingic acid, Cgg H^g O4, was discovered in a fat obtained 

 from a species of dolphin. This acid is likewise solid only at low 

 temperatures. Under the influence of nitrous acid, it undergoes a 

 change ; but whether an isomeric acid is produced is not yet known. 

 Neither has it been determined whether it yields sebacic acid on dry 

 distillation, 



"The hrassinic acid .'is found in the rape-seed oil. It melts at 

 32 - 33° C, is changed in the air when heated to 100° C, and is very 

 soluble in alcohol, as are all the members of this series. An isomeric 

 modification results from tlie action of nitrous acid, 



" The erucaic acid, C44 H42 O4, is found in the fatty part of the white 

 mustard. It melts at 34°, and is very soluble in alcohol. Farther 

 than this, we know nothing concerning its properties, 



" The moringaic acid was found in the poppy oil. It has been 

 but little studied, 



" Finally, the hypogseic acid, which has formed the subject of our 

 investigation, is a constituent of the oil obtained from the fruit of the 

 African plant, the Arachis hypogsea, which is known in commerce as 

 the ground-nut or pea-nut, 



" To obtain it, the lead salt is first prepared from the crude mixture 

 of the acids which occur in the oil, according to the ordinary method 

 of preparing oleate of lead. This lead salt, on decomposition with a 

 mineral acid, yields a reddish-yellow mass, which, at common winter 

 temperatures, is a mixture of a reddish-yellow oil, and a white crys- 

 talline substance ; the latter is the pure acid, the former the product 

 of oxidation by the air. From this mixture the pure acid can be 

 obtained by combining the whole with baryta, repeated recrystalli- 

 zation of the product from an alcoholic solution, and decomposition of 

 this purl salt with a mineral acid. Thus purified, the hypogseic acid 

 forms a white solid fat, which melts at 34° C.,and then readily oxidizes 



