194 M. Chevreul on Fatty Bodies, and [Sept. 



earthy salt that was thus formed, he was able to estimate the 

 quantity of base that had been united with the margarine in each 

 of the compounds. These were found to be as follows : 



Margarine 100-00 



Soda 12-72 



Margarine 100-00 



Barytes 28-93 



Margarine 100-00 



Strontian 20-23 



Margarine 100-00 



Lime 11-06 



By calculating the amount of oxygen contained in these 

 differer. ',ases, it appears that in these compounds, as well aa 

 in that of magarine and potash, the margarine unites to about 

 three per cent, of oxygen. By boiling margarine with the sub- 

 acetate of lead, a compound was formed of margarine and the 

 protoxide of lead, which consisted of 100 parts of margarine to 

 83-78 parts of the protoxide of lead ; but as this would contain 

 nearly six per cent, of oxygen, it was supposed to be a sub-soap, 

 or one with an under proportion of base. By boiling together 

 the saturated solutions of nitrate of lead and soap of potash, a 

 neutral compound of margarine and oxide of lead was procured, 

 composed of margarine 100 parts, and 41-73 parts of oxide of 

 lead ; the oxygen in this quantity of oxide of lead is 2*98. 



M. Chevreul next proceeds to examine the compounds formed 

 by the union of the jiuid fat with the different bases. It was 

 found more difficult to ascertain the composition of these soaps 

 than of the soaps of margarine, because it was less easy to pro- 

 cure the fluid fat in a uniform state, always exhibiting the same 

 properties ; under one form in which it was procured it remained 

 fluid almost to the freezing point of water, while another spe- 

 cimen congealed at 43°. The soap of the fluid fat and barytes 

 was found to consist of fluid fat 100 parts, and barytes about 

 27 parts, which will give 2-83 per cent, of oxygen in the com- 

 pound. The soap of fluid fat and strontian consists of 100 parts of 

 the fluid fat to 19-38 of strontian, containing 2-81 parts ofoxygen ; 

 and the soap of the fluid fat and the protoxide of lead may be 

 estimated at about 100 parts of the fluid fat to 114-81 of the 

 oxide of lead. There was some difficulty in estimating the 

 composition of the soap of the fluid fat and potash, in conse- 

 quence of the tendency which these bodies have to form a 

 super-soap as well as a neutral soap ; but by a careful, synthe- 

 tical experiment, the author^ascertained the proportion of the 

 constituents to be 100 parts of the fluid fat to 16-58 of the base ; 

 this quantity of base contains 2*82 parts of potash. The soap 

 of the fluid fat and soda consists of 10*11 parts of alkali to 100 

 parts of fat. M. Chevreul then states the composition of some 

 of the other saponaceous compounds formed by the Jiuid fat ; 



