OVMIIK AND BUTTER. gj$ 



become very thick and adhering ftrongly to the fides ©f the 



bottle, gradually became detached, and foon afterwards were 



converted into a while liquid, in the midft of which fwam a 



yellow mafs of excellent butter. Hence it follows, that the 



butter exifts in the milk, and is feparated when the milk, • g 



being deprived of the vital action, is left to ilfelf. At this 



lime, either by the formation of an acid arifing doubtlefs from 



a decompotition of the extractive matter, or perhaps from the 



lefs fpecific gravity of the- butter compared with that of the 



cheefe; for the butter begins to Separate almofl at the moment 



that milk is poured into a veflel ;— -the milk is decompofed, 



the cream rifes to the top, and from thislaft, by agitation, and 



more particularly by the affiftance of a temperature between 



15° and 20° (66° to 77° F.), butter is obtained together with Proeefs of totf. 



butter-milk, which is a white very mild liquor, in which fome terni ^ ' 



butter and cheefe are fufpended in a very divided flate. But 



the butter thus obtained is not pure : It ftill contains a portion 



of cheefe amounting fometimes to the iixth part of its weight; . 



and this is the caufe of its fpeedily becoming rancid, parti* 



cularly in Cummer. When the cheefy matter is feparated by 



fqfion, the butter may be kept a long time. It is true indeed, 



that by this fulion it acquires an acridnefs which greatly limits 



its ufes, and makes it unfit to be employed in frying; but this } ^ 



difadvantage might be remedied by keeping the temperature *"<* 



much lower than is ufual. Clouet firft made this observation; 



and hence the following procefs may be adopted for purifying 



butter, or feparating the cheefy matter without giving it a bad 



tafte. 



1 . Let the butter be melted on the water bath, or at a degree 'Purification of 

 Of heat not exceeding the 66° of Reaumur. 2. Keep it melted bu , tt( 7 b , y fufiort * 

 till all the cheefy matter is collected in white flakes at the bot- the chce/y part. 

 torn of the veflel, and the melted butter is tranfparent. 3. At 

 this period decant it, or pafs it through a cloth. 4. Let it be 

 cooled in a mixture of equal parts of pounded ice and fea-falt; 

 or if ice cannot be procured, then in cold fpring-water, making 

 ufe of broad mallow veflels. Without this precaution the butter 

 would become lumpy by cryftallizing, in which Irate it could 

 not be ferved at table. Beftdes which, the parts being con- 

 denfed by this fudden cold, are found to reiift the action of the 

 air more effectually. With this laft intention it is aifo proper 



to 



