DAIRY LABORATORY GUIDE 45 



liquid. In making the test, fill the test bottle to the zero 

 mark with water or a similar liquid; then remove with a strip 

 of blotting paper all drops adhering to the neck within, and 

 insert the plunger. If the bottle is graduated accurately, 

 the liquid will rise from the zero mark to the 5% mark 

 when the first part of the plunger is submerged, and to the 

 10% mark when the second part of the plunger is sub- 

 merged. Any test bottle showing a variation of .2 % is not 

 sufficiently accurate to insure a reliable test. 



2. Liquid Method. A very satisfactory way is to color 

 some water with dark ink; then transfer this to the bottle to 

 be tested and fill to the zero mark. Remove all drops adher- 

 ing to the neck within and add 1 c. c. of the water from a 

 burette or pipette. If the graduations are accurate, the 

 liquid will then extend to the 5% mark. Add another cubic 

 centimeter of the liquid, which should bring the surface of the 

 liquid to the 10% mark. Any fraction of the scale may be 

 tested by adding .2 c. c. of the liquid, which represents one per 

 cent on the scale. 



Cream Bottles. The same methods employed in testing 

 milk bottles may be used in calibrating cream bottles. 



Pipettes. The liquid method can be used to advantage 

 in testing the pipette. Close the tip end of the pipette and 

 then add from a burette or from a standardized pipette 17.6 

 c. c. of the liquid. If the pipette is accurately made, the 

 liquid should reach to the mark on the neck. 



How To CLEAN GLASSWARE 



It is well to empty the test bottles into an earthen jar 

 immediately after completing the test and before the butter- 

 fat becomes crystallized. The test bottles will need to be 

 shaken while being emptied to loosen the lime sediment cling- 

 ing to the bottom. 



