1818.] their Combinations with Alkalies. 263 



sis which was adopted : the soap, after being separated from the 

 mother-water, was dissolved in boiling water : by cooling and 

 rest a quantity of pearly matter was deposited, which is consi- 

 dered as a super-margarate of potash, and the fluid becomes 

 alkaline. It was filtered and neutralized by tartaric acid ; by 

 rest there was a new product of super-margarate, and a quantity 

 of alkali was set at liberty ; the same process as that employed 

 above was repeated until there was no longer a pearly deposit ; 

 an oleate of potash was then obtained, which was decomposed 

 by tartaric acid. By this process the soap was reduced to the 

 super-margarate of potash and the oleic acid. Our next object 

 is to examine the relative proportion of these two ingredients as 

 procured from the different kinds of soap. The super-margarates 

 were first very carefully prepared by frequent ablution in distilled 

 water and in alcohol, and they were then decomposed by the 

 hydrochloric acid in the manner that has been described above 

 as applied to the soap of hog's-lard : the following results were 

 obtained : 



Super-margarate of human fat. 



Margaric acid 91-8848 100-00 



Potash 8-1151 8-85 



Super-margarate of the fat of the sheep. 



Margaric acid 92-012 100-00 



Potash 7-988 8-68 



Super-margarate of the fat of the ox. 



Margaric acid 91*925 100-00 



Potash 8-075 8-78 



Super-margarate of the fat of the jaguar. 



Margaric acid 92-075 100-0 



Potash 7-925 8-6 



Super-margarate of the fat of the goose. 



Margaric acid 91.94 100-00 



Potash 8-06 , 8-77 



The super-margarate of the fat of the hog is composed of 100 

 parts acid and 8*8 parts of potash, so that all these super-mar- 

 garates are analogous in their composition. 



Equal proportions of water and of these super-margarates were 

 boiled together to observe whether they were acted upon in a 

 similar manner; and the principal difference that was perceptible 

 was the greater or less degree of semi-transparency of the solu- 

 tions. The super-margarate from the ox was less opaque than 

 that from the sheep, and this was less than that from the hog. 

 It is stated that a mixture of one part of this last super-marga- 

 rate with 10 of boiling water seemed to lose its transparency 



