fatty Suisia}ices,and on their Comlnn at ions with the Alkalis. 20\ 



Yielded margarine 100, and potash 8"55. The washinajs when 

 filtered and evaporated contained pot-i'^h and a trace of margarine. 

 If instead of putting the combination of margarine saturated 

 with alkali in plenty of water, we put it in a small ({iiantity of this 

 liquid, it swells, becomes semi-transparent by absorljing it, and 

 forms a thick mucilage \vhich exhibits pearly matter when it is 

 shaken. In this case the mass of water not being sufficient to 

 overcome the whole of the affinity of the pearly matter for an 

 excess of potash, it happens that the decomposition of the sa- 

 turated combination is only partial, and it is the part which is 

 not altered which absorbs the water, and forms with it a muci- 

 laginous liquid, by retaining it among its molecules, if we throw 

 the whole upon a filter, after having mixed enough of water with 

 it to facilitate the filtration, analysis demonstrates less potash 

 than in the saturated combination, and more tlian in th-j pearly 

 matter ; which proves that the decomposition has been but 

 partial. 



30. When we put three grammes of saturated combination 

 in 100 grammes of boiling water, we obtain a solution which is 

 perfectly limpid while tiic li(juor is warm, and wliich even may 

 be filtered. This solution upon cooling deposits abundance of 

 mother of pearl matter, and afterwards becomes thick. When it 

 is completely cooled, it is precisely like cold water in which we 

 have put a greatquantity of pearly comiiination : only the mucilage 

 is much more homogeneous. The filtered liquor contains i)otash 

 and some atoms of margarine ; for it is not rendered turbid by 

 the acids, except when it has been concentrated. 



31. It follows from what has been said: 1. That the satu- 

 rated combination of margarine is decomposed into mother of 

 pearl substance, andjnto potasli, by a great mass of cold water; 

 2dly, that a little of this liquid only decomposes a part of it; 

 that what is not decomposed absorbs Avater, and forms a thick 

 semi-trans]jarent mucilage ; 3dly, that when the action of the 

 water is assisted by that of caloric, the saturated combination 

 may be completely dissolved, and that by cooling there is formed 

 pearly matter, and a thick umcikige of saturated combination, 

 if the water l)e not always in execs-:. 



32. The saturated combination is dissolved in boiling alcohol, 

 and partly precipitated upon cooling, without undergoing de- 

 composition. 100 parts of boiling alcohol of a gravity of 0834 

 appeared to me to dissolve only 8-93. When we dilute this so- 

 lution in v.'ater, v/e obtain pearly matter in the form of very bril- 

 liant small crystals. If the alcoliol does not decompose the sa- 

 turated combination as water does, this is owing to its dissolving 

 equally well potasli and margarine ; whereas water dissolving 



only 



