TESTING DAIRY PRODUCTS BY THE BABCOCK TEST. 63 



pounds of butter fat, which would make about 5 pounds of but- 

 ter containing 85 per cent fat. If cream tests 20 per cent fat, 

 100 pounds of that cream contains 20 pounds of butter fat, 

 which would make about 23.6 pounds of butter. 



APPARATUS. 



The principal apparatus used in the test is here described. 

 Special forms and modifications used in determining the butter 

 fat in different dairy products are given in the applications of 

 the method to special cases. 



The test bottles. The general form of the bottle is shown in 

 figure 1 on the opposite page. Several different styles used for 

 different purposes are described beyond. All of the bottles have 

 graduated necks reading in percentages of the amount of milk 

 or cream used. The dimensions of the scale on the necks 

 should be uniform and the lines should run straight across the 

 neck, and not obliquely, as is sometimes the case. 



When new, the lines and numbers of the scale are usually 

 blackened so that they are easily distinguished, but after the 

 bottles have been cleaned a number of times the color may be 

 washed away, leaving the lines indistinct. The color may be 

 restored by rubbing the scale with a lead pencil, or with a cloth 

 having a little black paint upon it. 



In order to avoid the possibility of errors, the bottles should 

 be numbered. This is conveniently done by having a number 

 stamped on a copper ring which is slipped over the neck, or by 

 having a spot etched on the upper part of the neck so that the 

 number can be marked upon it with a pencil. 



The pipette. The form of pipette commonly used is shown in 

 the accompanying cut (fig. 3). That for milk should deliver 

 17.6 cubic centimeters and for cream 18 cubic centimeters, when 

 filled to the mark. 



Acid Measure. The best measure for general use is a grad- 

 uate or cyclinder of glass, (fig. 4) with a lip to pour from. 

 When filled to the mark it contains 17.5 cubic centimeters. 



Several automatic pipettes and convenient devices have been 

 invented for handling acid on a large scale for use in factories 

 where a large number of tests must be made daily. These cost 

 from $5 to $50 and are great time savers. Two very satisfac- 



