THE ANALYSIS OF MILK 7 



taking care that no air bubbles are retained in the space 

 between the upper and lower bulbs (see Fig. 4) ; when 

 the upper bulb is partially below the surface, raise to an 

 upright position and immerse the lactometer to the 30 



FIG. 4. Vieth's Lactometer. 



mark, and let it find its own level. When steady read off 

 the point where the surface of the milk cuts the stem ; 

 this point is not visible, as the milk is drawn up round 

 the stem by capillary attraction (Fig. 5), and must be 

 mentally estimated. Some little practice is required 



