288 ilf. Chevreul on Fatty Bodies, and [Oct. 



and alcohol on the pearly matter proved that it contained a per- 

 ceptible quantity of oleic acid ; after this was separated, the 

 following results were obtained. The substance was very bril- 

 liant, and perfectly white ; it had only an extremely slight odour; 

 it was not dissolved in warm water, but it was completely soluble 

 in a solution of alkali. By cooling, this solution was converted 

 into potash and the super-margarate of potash, exhibiting all the 

 properties which had been formerly described as belonging to this 

 substance. By analysis, it yielded, 



Margaric acid 100-00 



Potash 8-77 



The margaric acid was almost without odour ; it crystallized 

 in small, fine, radiated needles. When melted at the temperature 

 of 158°, it congealed at 131° ; but as the bulb of the thermometer 

 was not completely covered in this experiment, and as the acid 

 was very turbid at 132 , 5°, probably this may be more exactly the 

 proper melting point. 



The oleatc of potash, after it had ceased to yield any more 

 pearly matter, was decomposed ; the acid was left at the temper- 

 ature of the atmosphere, and a crystalline substance was sepa- 

 rated. After this separation, the following properties were 

 found in it : it was of a brown orange colour, much deeper than 

 that of the oleic acids of the fat of the hog, the sheep, the ox, 

 &c. ; but this colour probably depended upon something distinct 

 from the oil itself, whether proceeding from the decomposition of 

 a portion of the oil, or from some other cause. This oleic acid 

 had a strongly marked fishy smell, which it communicated to its 

 combinations with barytes, strontian, and the oxide of lead. 

 These oleates produced the following results by analysis. 



Oleic acid 100-00 



Barytes 26-77 



Strontian 19-41 



Oxide of lead 81-81 



We now come to the examination of the concrete fatty matter. 

 After being drained on bibulous paper, it was acted upon by 

 boiling alcohol, by which a considerable quantity of elai'ne was 

 separated; during this process the concrete matter became 

 coloured. It was then melted ; a thermometer plunged into it 

 descended to 70°, and as it became solid, rose again to 80-5°. 

 The action of heat entirely removed from it the odour of leather. 



Nine parts of alcohol, of the specific gravity of -795, dissolved 

 five parts of the concrete fatty matter. The solution yielded by 

 cooling, 1. Small radiated needles of the most beautiful white 

 colour; and, 2. Needles of a yellow colour : there remained a 

 viscid mother-water, of a brown colour ; and it seemed as if in 

 this operation the colouring principle was increased in its quan- 

 2 



