88 



Testing Milk and Its Products. 



show one-tenth of one per cent., if the fat fills only one 

 division of the scale or less. 1 



The double-necked bottle is very convenient for the 

 testing of separator skini milk, thin butter milk and 

 whey. The milk, acid and water are added to the bottle 

 through the large side-tube; the mixing of milk and acid 

 must be done with great care, so that none of the con- 

 tents is forced into the fine measuring tube and lost; it is 

 best to add half of the acid first and mix it with the milk, 

 and then add the rest. When the fat is in the lower end 

 of the measuring tube, it can be forced into the scale by 

 pressing with the finger on the top of the 

 side tube. 



In placing the double-necked bottle in 

 the tester they should be put with the 

 filling tube toward the center so as to 

 avoid any of the fat being caught be- 

 tween this tube and the side of the bot- 

 tle when it resumes a vertical position. 

 This test bottle is more fragile and ex- 

 pensive than the ordinary Babcock bot- 

 tles, and must be carefully handled; it 

 has recently been made of heavier glass 

 and this form is to be highly recom- 

 mended. 2 



100. The double-sized skim milk bottle is 

 of no particular value. It is difficult to 

 obtain a thorough mixture of the milk and the acid in 



i Wis. experiment station, bull. 52; Penna. experiment station, report 

 1896, p. 221. 



2 During the past year a copper double-necked test bottle with a detach- 

 able graduated glass neck was designed and tried by one of us (F.), but no 

 special advantages over the glass bottle has so far been found for it. 



FIG 37 Wagner 

 skim milk bottle. 



