STANDARDIZATION OF. CREAM. 267 



sold in the form of milk, cream and butter at retail 

 prices, as compared with the wholesale butter fat 

 value of milk. 



In the following the cost of manufacture and the 

 expenses incident to selling the product will not be 

 considered, the aim being to point out the possible 

 value of butter fat as sold in different products. 



Cream or milk is usually sold both by measure and 

 weight. The weight of cream varies according to its 

 fat content. Pure butter fat has a specific gravity 

 of .9 against 1, the specific gravity of water; conse- 

 quently the richer the cream the lighter it is, and 

 the thinner it is the heavier it is. Generally speak- 

 ing the cream usually put upon the market weighs 

 about 8.3 lbs. per gallon. Cream containing from 

 18 to 22 per cent butter fat weighs a little more than 

 this, while cream, testing from 25 to 40 per cent 

 weighs a little less per gallon. Milk does not vary 

 in weight to any appreciable amount, therefore, no 

 difference in weight of milk of different richness is 

 made. 



The explanation of a few problems is necessary in 

 order to illustrate methods that may be used in de- 

 termining the approximate amount of butter which 

 can be made from a given quantity of milk and the 

 possible value of the butter fat when sold in the 

 form of butter, cream and milk; these problems to 

 be based upon an assumed retail price. Problems 

 are also necessary to show the amount of butter fat 

 in a quart or a gallon of cream of any richness and 

 the price of cream according to the price of butter 

 fat. 



