New Organic Acids. 113 



acid. The odour of the butyrates is exactly that of fresh butter. 

 The above salts are inodorous in the dry state, even when heated 

 to 100° C. Their composition is easily deducible from their con- 

 stituent acids. To shew, however, the great differences among 

 the capacities of saturation of these acids, M. Chevreul details 

 the following- composition of the salts of barytes : 



100 of butyric acid neutralize 97.58 of barytes. 



The phocenate of barytes crystallizes in large polyhedrons, 

 which appear to be octohedrons; the butyrate crystallizes in long 

 prisms ; the caprate in small globular crystals. The saturated 

 solution of butyrate of lime contains 17 of salt for 100 of water 

 at 15° C. ; but at the boiling point it is less soluble, like its base, 

 and forms a crystalline mass. The caproate of barytes evapo- 

 rated spontaneously crystallizes in needles ; evaporated at 18°, 

 in hexagonal plates. The hircic acid gives to mutton broth the 

 flavour which distinguishes it from that of beef. It forms a 

 sparingly soluble salt with barytes, and a deliquescent one with 

 potash. 



The disagreeable smell of leather dressed -with fish oil, is as- 

 cribed by M. Chevreul to the decomposition of the phocenic acid 

 contained in this oil; for water, to which a few drops of this acid 

 have been added, takes this odour after some time. 



The stearic, margaric, and oleic acids, in their habitudes with 

 heat, correspond to benzoic acid ; the volatile acids, described in 

 the present memoir, correspond to the acetic. Among the fatty 

 bodies, not acid, there are some, like cholesterine (and ethal ?) 

 which experience no alteration on the part of the most powerful 

 alkalis ; while other species, as the stearines, oleine, butyrine, pho- 

 cenine, hircine, are all converted under the alkaline influence into 

 a sweet principle on the one hand, and, on the other, into fixed or 

 volatile acid fats ; and it is possible that these latter species may 

 be composed immediately of the same acids, and a sweet anhy- 

 drous principle acting as a base. However this may be, we can- 

 not help approximating the substances which afford odorous acids 

 by saponification to the group of those ethers, which are regarded 

 as compounds of acids with alkohol. — Ann. de Chim. et de Phys. 

 xxiii. 16. 



Vol. XVI. I 



