12.32 



RiiRAi, School Leaflet 



condition. Hold the bottle by the upper end of the neck, letting il hanjj; 

 in a perpendicular position, on a le\a'l with the eye. Read the marks, 



or <2;raduations, at the extreme top and 

 bottom of the column of fat. The difference 

 l^etween these is the percentaj^e of fat in 

 the milk. Some test bottles are made to 

 read as high as lo per cent, while others 

 read only to 8 per cent. Each percentage 

 g ~^^^^a^H^^H ^^^ ^^^ number marked on the glass, and on 



L L-JHBHBBKBBH the lo-per-cent bottles there are five small 



spaces each representing 0.2 per cent be- 

 tween these principal marks. Thus, if the 

 top of the column of fat is even with the 

 third short mark above the 7 mark, the 

 top reading would be 7.6; and if the bottom 

 is halfway ])elweon the first and the second short marks above the 3 

 mark, tlic bottom reading would be 3.3; the 

 difference is 4.3, which is the percentage of 

 fat, or the number of pounds of fat in 100 

 pounds of the milk tested. On the 8-per- 

 cent bottles there are ten small spaces be- 

 tween each percentage mark, and each space 

 represents one-tenth of one per cent. 



Fig. 4. — Putting the milk into 

 the test bottle. The pipette is 

 held at an angle with the test 

 bottle and its point against the 

 inside of the neck 



One c.c. nieans 

 about 20 drops. 



Notes 

 I cubic centimeter, or 



Fig. 5. — Mixing milk and acid. 

 A rotary motion with the bottle 

 not pointed toward the face 



If the column of fat is clouded with white specks, 

 probably the acid was not strong enough, or not 

 enough was used, or the heat was not high enough. 



If the column of fat is clouded with dark sj^ecks, 

 probably the acid was too strong, or too much was 

 used, or the heat was too great. 



Always keep the acid bottle closed when not in 

 use, or the acid will lose strength. Remember that 

 it is a poison and corrosive. 



POINTS TO BE ESPECIALLY NOTED IN MAKING THE 



BAB COCK TEST 



H. E. Ross 



I. Be sure to mix the sample of milk thoroughly before drawing it 

 out with the pipette, but avoid making air bubbles. 



Fig. 6. — Whirling the 

 samples 



