DAIRY RULES (Continued) 



(13) 



10. The parallelogram method of standardization was devised by Pro- 

 fessor R. A. Pearson, and is illustrated as follows: 



B D 



In the rectangle let A always represent the percentage of fat wanted in 

 the standardized milk. Let B represent the per cent of fat in the milk or 

 cream of the higher fat content. Let C represent the per cent of fat in the 

 milk or cream of the lower fat content. The proportion D is secured by 

 subtracting C from A; and the proportion E is secured by subtracting A 

 from B. D represents the proportion of B to be taken, and E represents the 

 proportion of C to be taken. 



These proportions give the parts of the milk or cream of the different 

 percentages of fat which when added together in these proportions will give 

 the desired percentage of fat in the standardized milk or cream. These pro- 

 portions when added together and divided into the amount desired will give 

 in pounds the value of each part. This multiplied by the number of parts 

 found in each proportion will give the number of pounds of each to use. 

 To illustrate: 



B=22 



D = l=parts of 22%. 



E = 18= parts of 3% 



95 pounds of 4 per cent milk is desired. It is to be made from milk 

 testing 3 per cent and cream testing 22 per cent. 



18+1 = 19 parts. 95-=- 19 =5. 5 represents the value in pounds of 

 one part or proportion. Then 5 xl8 =90 pounds of 3 per cent to use. 5x1 = 

 5 pounds of 22 per cent to use. 



1 1. Where milk is to be reduced by adding skimmilk. 



By dividing the percentage of fat in the milk wanted by the percentage 

 of fat in the milk on hand will give the percentage or the amount of the milk 

 to be used, and the rest must be added as skimmilk. Thus: 



300 pounds of 5 per cent milk is to be mixed with skimmilk to form 4 

 per cent milk. (4-5-5. = .80.) Then 300 pounds represents 80 per cent of the 



