Improvement of Missouri Herds. 



385 



specific gravity is 1.034. The richer a sample of milk in casein, 

 milk sugar and ash, the greater its buoyant power and the higher 

 specific gravity, which results in the lactometer stem not sinking 

 to so great a depth as it would if less casein, sugar and ash were 

 present. Hence, we find skim milk having a greater specific grav- 

 ity than normal milk. On the other hand, the addition of water 

 to milk lowers the specific gravity below 1.029, almost proportion- 

 ally with the amount of water added. Milks very rich in fat have 

 a lower specific gravity than milks which contain less fat. This 

 is due to the additional fat in the milk lowering its specific grav- 

 ity. A skilled operator can readily determine whether the in- 

 crease or decrease in the specific gravity of milk is due to varia- 

 tion in the water or in the fat content of the milk. 



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The Lactometer. 



QUEVENNE'S LACTOMETER. 



The lactometer is a piece of apparatus for determining the 

 specific gravity of milk. It consists of a bulb (see Fig. 28.) 

 weighted with mercury, attached to a glass tube of cylindrical 



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