LESSONS ON DAIRYING FOR RURAL SCHOOLS. 11 
Home projects.— The weighing of milk and keeping a record of the 
same belongs to project A type, and may be assigned alone as a 
short- time project. 
Correlations. — Construct various problems showing the difference 
and the percentage of difference in the weekly and monthly milk 
record of two or more cows; others showing the percentage of gain 
or loss in the milk record of a cow in consecutive weeks or months. 
LESSON IV. TESTING. 
Sources of information. — Bureau of Animal Industry (U. S. De- 
partment of Agriculture) Document A-12, Chemical Testing of Milk 
and Cream. 
Fig. 6.— Outfit for testing milk. 
Topics for study. — A simple Babcock tester should be a part of the 
equipment of every rural school (fig. 6). A machine may be pur- 
chased for a small sum or, in case no fund for its purchase is avail- 
able, one can probably be borrowed from some dairy farmer in the 
district. 
Require the pupils to bring to school samples of milk and give 
them practice in testing milk. First have the test made by two 
students, and be certain the entire class understands each step in 
the process. Then divide the class into groups and supervise them 
until they are reasonably accurate, using milk from one cow only 
as a check. When they have learned to make the test accurately, 
