DAIRY HUSBANDRY 
37 
SERIES E. 
Use of the Lactometer. 
Ma terials necessary for 10 students. 
2—Pounds butter salt (best grade). 
1—gallon distilled water. 
EXERCISE NO. 28 
Object: To test the accuracy of a lactometer. 
Procedure: When a new lactometer is purchased and no tested lactome¬ 
ters are available for checking the accuracy of the new one, 
it may be necessary to use some other method for checking. 
A. Place exactly 300 cc. of distilled water into each of 3 containers 
labeled A, B, and C respectively. To cylinder A, add 9 grams 
of pure dairy salt, to B, add 12 grams of pure dairy salt, and to 
C add 15 grams of pure dairy salt. Allow the salt to dissolve 
and bring the mixture to exactly 60° F. 
R. Insert the lactometer to be tested successively into each of the 
three solutions, A, B, and C, carefully wiping the lactometer 
before each insertion. The readings on the lactometer should 
indicate 1.022, 1.029, and 1.036 specific gravity respectively 
for A, B, and C. 
Note: Be sure to have the solution well mixed before insert¬ 
ing the lactometer. 
Observations: 
Salt solution 
Correct reading 
Lactometer reading 
Error 
A 
1.022 
B 
1.029 
C 
1.036 
Conclusion: 
Questions: (1) Define the term specific gravity. 
(2) What is the object of knowing the specific giavity of certain 
lots of milk? 
(3) What is a lactometer, and on what principal is it based. 
(4) Describe fully the markings on the neck of a Quevene lac¬ 
tometer. 
Reference: F. & W. If 109, 110, 118, 118a; Van S. pp. 175-179; Jud. pp. 
91-101; St. pp. 136-143. 
