212 THE dairyman's manual. 



permanently cold spring or of ice is necessary under this 

 system. The use of this method of raising cream is 

 rapidly extending and is indispensable in the manage- 

 ment of a public creamery. 



The shallow pan system is the most used, and is practi- 

 cally universal in private farm dairies; it has the advan- 

 tages of convenience and simplicity, and under the best 

 conditions of practice is quite as effective in every way as 

 the deep pail system. No water or cooling is required, 

 but some method of heating is desirable in the winter. 

 An airy, dry, deep cellar with thick walls, and well-con- 

 structed, as hereafter explained, famishes every desirable 

 or requisite condition for raising the cream under this 

 simple system. 



The centrifuge is a comparatively new introduction in 

 the busmess of dairying, but its value and adaptation for 

 the economical and effective working of dairies large or 

 small are boundless. This useful machine operates on 

 the principle that centrifugal force in a confined vessel, 

 properly constructed, will throw the denser and heavier 

 particles of a fluid to the outer circumference, and thus 

 compel the lighter particles to seek the center. It is 

 really the adaptation of the principle of gravity to a 

 horizontal position, compelling the lighter particles to 

 rise to the top and the heavier ones to sink to the 

 bottom, so to speak, by the exercise of this force exerted 

 horizontally instead of perpendicularly. Like all other 

 operations of natural dynamic laws it is exceedingly 

 simple — when it is understood. 



In considering the nature of cream the cause of its 

 varying yellow color is worthy of some thought. Why is 

 cream yellow, and more deeply yellow in some cows than 

 in others? The author has given much study to this in- 

 teresting question, and with the following result. Yellow 

 is a diluted red, or at least red is a concentrated yellow^ 

 Yellow pigments, when concentrated, always appear to 



