126 MARKET DAIRYING 
Reducing Cream with Skim-milk. When a definite 
quantity of standardized cream is called for, determine 
first the amount of original cream (cream as it leaves the 
separator) required according to the following rule: 
Rule: Multiply the number of pounds of standardized 
cream called for by its test and divide the product by the 
test of the original cream. 
The difference between the amounts of original and 
standardized cream represents the amount of skim-milk 
required. 
Problem: How many pounds each of 45% cream and 
skim-milk (zero test) are required to make 60 pounds of 
18% cream? 
Applying the above rule we get, 
(60 X 18) + 45—=24—=No. lbs. of original cream. 
60 — 24 = 36 = No. Ibs. of skim-milk. 
Milk may be standardized in the same way. 
Mixing Two Milks or Two Creams, or Milk and 
Cream, of Different Richness. In the preceding two 
formulas the test of the skim-milk was considered zero. 
When milks or creams of different tests are mixed the 
calculation becomes more difficult. Pearson, however, 
has devised a method by which calculations of this kind 
are very much simplified. This method is as follows: 
Draw a rectangle with two diagonals, as shown below. 
At the left hand corners place the tests of the milks or 
creams to be mixed. In the center place the richness 
