operation of Test Chums. 41 



Churn tests. — The first butter factories or cream- 

 eries were managed upon what is known as the 

 cream - gathering system : that is, the cream was 

 raised and skimmed upon the farm, and it alone 

 taken to the factor^'. It was soon found that the 

 cream varied considerably in the percentage of fat 

 that it contained, and, moreover, that a consider- 

 able amount of milk could be mixed with the 

 cream without being detected by ordinary means. 

 In other words, the managers of factories learned 

 that cream as it came to them was even more 

 variable in its percentage of fat than whole milk. 

 In all of the earlier factories the cream was paid 

 for simply bj' measure, and it became necessary to 

 devise some means of making an equitable division 

 among the different patrons, and of protecting the 

 factory from loss. To do this, what was known 

 as test churns were devised. At the time of 

 gathering the cream, a small sample ( a pint or 

 quart) of each patron's cream was taken in a sep- 

 arate vessel. These were taken to the factory 

 and churned separately' in small tin cans, and the 

 butter made up from each. The butter -producing 

 power of the single pint or quart was taken as a 

 measure of the butter value of the whole amount 

 of that patron's cream, and the proceeds were ap- 

 portioned accordingly. This method was much more 

 just than a simple measure of the cream, but it 

 was very cumbersome. It required delicate manip- 

 ulation in order to make all of the little pats of 

 butter of the same water content, and the small 



