THE BABCOCK TEST 53 
many tests are made a graduate of this kind saves time 
in filling, but should be made to hold twenty-five charges. 
H. A cream scaies is shown in Fig. 15. Also see 
Figs. 27 and 28, pages 71 and 72. 
Acid. The acid used in the test is commercial sul- 
Fig.15.—Cream scales. 
phuric acid having a specific gravity of 1.82 
to 1.83. When the specific gravity of the 
acid falls below 1.82 the milk solids are not 
properly burned and particles of curd may 
appear in the fat. On the other hand, an 
acid with a specific gravity above 1.83 has 
a tendency to blacken or char the fat. 
The sulphuric acid, besides burning the 
solids not fat, facilitates the separation of 
the fat by raising the specific gravity of the 
medium in which it floats. 
Sulphuric acid must be kept in glass bot- pig 16 Show- 
tles provided with glass stoppers. Exposure gmannerot 
to the air materially weakens it. Peres 
Making a Babcock Test. The different steps are 
indicated as follows: 
1. Thoroughly mix the sample. 
2. Immediately after mixing insert the pipette into 
the milk and suck until the milk has gone above the mark 
on the pipette, then quickly place the fore finger over the 
