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 ; churned 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. 



