26 



II THE LACTOMETER. 



1. The lactometer is a hydrometer which indicates specific 

 gravities between 1.000. the gravity of water, and 1.0348. 



2. It is used to determine the specific 

 gravity of the milk. 



3. As the specific gravity varies with the 

 temperature, the observations are made at 

 a standard temperature of 60 Fah. 



4. The specific gravity of the average 

 milk at a milking of a healthy cow, prop- 

 erly fed and in a normal condition, varies 

 from 1.029 to 1.0348. The former num- 

 ber being the lowest or minimum gravity, 

 100 is placed at this point on the lactome- 

 ter ; is placed at 1.000, the gravity of 

 water; the intervening space is divided 

 into 100, and the graduations are con- 

 tinued to 120, which corresponds to the 

 specific gravity 1.0348. 



5. To apply the lactometer, the temper- 

 ature of the milk is first noted with the 

 aid of the thermometer; the lactometer 

 is then carefully inserted, taking pains to 

 avoid wetting the portion of the stem 

 above the milk, and to free the surface 

 of the milk from foarn. The degree 



o 



to which the instrument sinks is then 

 noted. Bearing in mind the effect of 

 temperature on the gravity, the inspec- 

 tor now decides whether the gravity will 



probably be below 100 at 60 Fah. If he 

 The Lactometer. 



thinks it will, he carefully cools or warms 



a sample of the milk, as the case may require, to 60 Fah., and 

 again inserts the lactometer. If it stands below 100, the gravity 

 is below that of any genuine milk. He carefully notices the 



