236 CHURNING MIXED MILKS. 



the covering to the globules being of different char 

 acter, those of one breed are ruptured more readily 

 than those of the other, and over-churning of a por- 

 tion of the product is inevitable. Think of churning 

 Jersey milk, which will make butter in eight minutes 

 (see Experiment X) , mixed with Dutch milk which 

 requires an agitation during sixty minutes (see Ex- 

 periment III) for the same produce. 



Experiment XV- 



Two samples of milk were selected which showed 

 considerable variation in the size of the globules. 

 Twenty fluid ounces of the Jersey milk were divided 

 into two parts ; the like quantity of Ayrshire milk 

 was similarly treated. 



Jersey milk. Average size of globules 5852" 



Ayrshire milk. " " " 7080" 



These milks were then cooled to 60°, and churned 

 by shaking in a Florence flask. 



Ten ounces Jersey milk. Butter came in five min- 

 utes ; chui-ned eighteen minutes. Product, one hun- 

 dred and thirty-six grains of butter. 



Ten ounces of Ayrshire milk. Butter came in 

 twenty minutes ; churned thirty minutes. Product, 

 76 grains of butter. 



Thus the 20 ounces of milk churned separately 

 produced 212 grains of butter, or a proportion of one 

 pound of butter to 44.75 pounds of milk. 



Ten ounces of Jersey milk plus ten ounces of the 

 Ayrshire milk mixed and churned in like manner. 



