114 Progress of Foreign Science. 



12. Facts subservient to the History of Cow-butter. By 

 M. Chevreul. 

 1. Fresh butter is a mixture of butter-milk and butter. To se- 

 parate these two substances, the fresh butter must he kept some 

 time melted in an oblong vessel. The butler milk sinks to the 

 bottom ; the melted butter is decanted into a filter, and received 

 in water at 40° C. This mixture being agitated, is then left to 

 settle. When the butter has again gathered on the surface of the 

 water it is skimmed off, and filtered anew. In this state M. Chev- 

 reul has examined it as pure butter. 



2. Butter-milk distilled, after being filtered, afforded an acid 

 product, having the smell of frangipane, (a French perfume,) and 

 it contained butyric acid, a trace of ammonia, and, apparently, 

 some acetic acid. 



3. One hundred parts of fresh butter, (from Murs, in Anjou,) 

 were formed of, 



Pure butter . . . 83.75 

 Butter-milk . . . 16.25 



Pure butter indicates acidity by litmus paper. One hundred 

 parts of boiling alkohol, specific gravity 0.822, dissolve 3.46 of 

 butter. The solution powerfully reddens litmus. 



Butter saponifies with potash in vacuo, without the production 

 of carbonic acid. One hundred parts are saponified by sixty of 

 potash, rendered caustic by lime ; and there are obtained, acid 

 fats insoluble in water, some sweet principle, and volatile acids 

 which dissolve in water. The insoluble acid fats are the mar- 

 garic, the stearic, (in small quantity,) and the oleic. In the 

 state of hydrates, they weighed 88.5 parts, and they melted at 

 40°. C. The solution of the sweet principle and the volatile acids 

 was distilled; the acids rose with most part of the water, and the 

 sweet principle remained in the retort, mingled with the bi-tartrate 

 of potash. When the sweet principle was separated from the 

 tartar by alkohol, it weighed 11.85 parts. The volatile acids are 

 three in number, the butyric, caproic, and capric. 



M. Chevreul treated butter with alkohol, in order to determine 

 the relation which its immediate principles bear to the fat bodies 

 described in his former researches. For the minute details of his 

 experiments, we must refer to the Memoir itself. His conclusions 

 are the following : 



" There exist, at least, two fluid substances in the oil of butter. 

 1. One soluble in every proportion in cold alkohol, not acid, and 

 which affords by saponification the sweet principle, and the acids 

 butyric, caproic, capric, margaric, and oleic." He gives this sub- 

 stance the name of butyrine, because it contains the butyric acid, 

 (or its elements,) to which butter owes its odour. 



2. The other has the properties of oleine. 



