THE LACTOMETER AND ITS USE 



39 



Board of Health lactometer, multiply the readings 

 by .29. In reading the lactometer, the point to 

 which it sinks in milk should be carefully noted. 

 Because of capillary attraction, a meniscus or curved 

 surface is formed on the surface of the liquid. The 

 point at which the reading should be made is on a 

 level with the liquid and not at the top of the miscus. 

 46. Influence of Skimming and Watering. Since 

 milk has a specific gravity varying from 1.029 to 1.034, 

 it follows, as previously stated, that any addition of 

 water necessarily lowers the specific gravity, and any 

 removal of the fats necessarily raises the gravity. 



FIG. 12. 



Position of lactometer in normal, skimmed, and watered 

 milk. 



Watered milk often has a specific gravity of 1.035. 1 

 When skimming alone or watering has been prac- 

 ticed, it is easily detected by means of the lactom- 

 eter ; but when milk is both skimmed and watered, 

 the lactometer results fail to reveal the fact. The 



