1818.] tlieir Combinations with Alkalies. 187 



entertained respecting it by preceding chemists, the author 

 gives an account of a new compound, which he had discovered 

 in examining the soap which is composed of hog's-lard and 

 potash. When this scap is digested in a large quantity ot 

 water, a part of it is dissolved, while a portion, which is inso- 

 luble, is deposited in the form of small brilliant scales, which he 

 calls pearly matter (matiere nacree). These scales were punned 

 by beino- repeatedly washed in cold water, and afterwards 

 dio-psted^in alcohol, to remove from them the soluble soap and 

 the various impurities which they contained; they were subjected 

 to the action of diluted muriatic acid, by which they were 

 decomposed, and a new animal principle was obtained, to which 

 the name of margarine was applied, in consequence of its pearl- 

 like aspect, and the property which it possesses of communicat- 

 ing the pearly lustre to the combinations which it forms with 



The properties of margarine are then described ; it is of a 

 pearly-white colour, without taste, of a faint odour, a little like 

 that of white wax, it is lighter than water, and at 134 * melts 

 into a perfectly limpid colourless fluid, which, by cooling, 

 crystallizes into brilliant white needles. By distillation, marga- 

 rine is partially decomposed ; it is insoluble in water, but is very 

 soluble in alcohol when heated to 167° ; as the alcohol cools, 

 the margarine is precipitated, or if the solution has been satu- 

 rated, the whole is converted into a solid mass. 



The pearly matter, formed by the combination of margarine 

 with potash, was next examined. All the potash being very 

 carefully separated from it by means of diluted muriatic acid, 

 and the quantity of muriate of potash thus formed being accu- 

 rately ascertained, it was calculated to be composed of 



Margarine 91-91 100-0 



Potash 8-09 8-8 



100-00 



Cold water has no action on the pearly matter; but boiling 

 water partially separates the potash from it. It is less soluble 

 in alcohol than margarine ; if water be added to the alcoholic 

 solution, a precipitate is thrown down, which appears to contain 

 a smaller proportion of potash than the pearly matter ; it was 

 found that about i of the alkali was united to the water. If the 

 substance which is separated from alcohol by water be t 

 dissolved in alcohol, it is deposited on cooling in its original 

 state, composed of 100 parts of margarine to 8*88 parts of 

 potash. 



M. Chevreul was then induced to examine, whether, if 



• The degrees of temperature in this abstract are always measured by Fahren- 

 heit's scale. 



