60 FIRST LESSONS IN DAIRYING 



Substituting, we get: 



X = ( 45 4 X Q 4 - 3 ) - 450 = 33-75 pounds. 



Problem 2. Suppose that the 450 pounds of milk 

 tested 4.0 per cent, and it is desired to raise it to 

 4.5 per cent, by extracting skim milk ; the amount 

 of skim milk to be extracted is determined from 

 the following formula : 



in which X equals number of pounds of skim milk 

 to be extracted, and A, B, and C are the same as in 

 the preceding formula. 

 Substituting, we get: 



2) = 5o pounds. 



4-5 / 



The test of cream can be raised or lowered in the 

 same way by the use of the two preceding formulas. 



The following simple plan, which may be used 

 with skim milk or with milks or creams of different 

 degrees of richness, is suggested by Prof. R. A. 

 Pearson, of Cornell University. 



Draw a square with diagonals as here shown. 

 At the left-hand corners place the per cents, of fat 

 in the milk or cream to be mixed. In the center 

 place the per cent, desired, and at the right-hand 

 corners place the difference between the center 

 figure and that diagonally opposite. These differ- 

 ences will represent the number of pounds required 

 of the material the test of which is horizontally 

 opposite. 



