TESTING BY THE LACTOMETER I23 



ity and the scale of the Quevenne lactometer is shown 

 as follows : 



SPECIFIC Reading of 



GRAVITY Quevenne lactometer 



1015 15 



1.020 20 



1-025 25 



1030 30 



^•^SS, etc 35, etc 



Corrections for temperature. — The Quevenne lac- 

 tometer is graduated to give correct results at 60° F. 

 When it is used in milk, the milk should be at 60° F., 

 or, if at some temperature above or below 60° F., a 

 correction of the lactometer reading must be made. 

 This correction can be closely made by adding to the 

 lactometer reading .1 for each degree above 60° F., 

 or by subtracting .1 for each degree below 60° F. 

 For more exact corrections, consult table on the fol- 

 lowing page. 



The Quevenne lactometer should carry a thermom- 

 eter, the scale of which is placed for convenience above 

 the lactometer scale. 



Process of using Quevenne lactometer.— The sam- 

 ple of milk to be tested for specific gravity is brought 

 to a temperature between 50° and 70° F. For con- 

 venience the milk is placed in a cylinder (Fig. 49), 

 which is nearly filled. The lactometer is carefully 

 lowered into the milk until it floats and is allowed to 

 remain half a minute or more. Then one reads and 

 records (i) the point at which the lactometer scale 

 comes in contact with the upper surface of the milk; 

 and (2) the temperature. The lactometer reading is 



