202 MODERN METHODS OF TESTING MILK 



21. CHANGING QUARTS OF MILK INTO POUNDS 



Rule. — Multiply the number of quarts by 2.15. Ex- 

 ample : How many pounds in 40 quarts of milk ? 40 

 X2.i5=:86 pounds. 



22. CHANGING DEGREES FAHRENHEIT INTO 



DEGREES CENTIGRADE 



Rule. — From the degrees F. subtract 32 and mul- 

 tiply the result by ^-9- Example: 162° F.^(i62 — 32) 

 x5-9=72° C. 



23. CHANGING DEGREES CENTIGRADE INTO 



DEGREES FAHRENHEIT 



Rule. — Multiply the degrees C. by 9-5 and add 32. 

 Example: 72° C.= ( 72x9-5 )+32= 162° F. 



24. FINDING THE TRUE AVERAGE 



Rule. — To find the true average per cent, of fat in 

 different lot^ of milk or milk products, tiud the zueight 

 of fat in each separate lot by Rule-i, add these amounts 

 and divide the sum by the total -u'eigJit of milk or milk 

 products. Example: What is the average per cent, 

 of fat in the following lots of milk? 



Pounds Per cent. Pounds 



of milk of fat of fat 



400 containing 4.3 17.2 



300 '' 34 10-2 



800 " 5-2 416 



100 " 31 31 



1,600 . 72.1 



