40 How to Make Creamery Butter on the Farm 



(B) shut and press down the rubber bulb (A). 

 The air pressure then forces neutralizer from the 

 bottle into the burette ("C"). When enough of 

 the liquid has been forced into the burette to flow 

 into the bulb (E) at the top of the tube, release your 

 pressure on the vent tube (B) and the rubber bulb 

 (A). The air pressure will then force the surplus neu- 

 tralizer back into the bottle so that the burette will 

 remain rilled only to the zero point. 



It is well to draw out a little of the liquid from the 

 burette to be sure that the tip (F) is rilled. You must 

 then, however, force more neutralizer into the burette, 

 so that it is again filled to the zero point. (The neu- 

 tralizer drawn off may be put back into the bottle.) 



Making the test. We are now ready to add the 

 neutralizer to the cream which we have measured out 

 into the glass. Do this slowly, drop by drop, by 

 pressing on the pinchcock (D) very gently. Stir the 

 cream constantly. At first the pink color caused by 

 adding a few drops of the neutralizer will disappear 

 quickly, but as the acid becomes neutralized the color 

 will disappear more slowly. As soon as a permanent 

 pink color is obtained, the acidity is neutralized. 



Reading the Test. 



The burette holds 10 c.c. of the neutralizer. When 

 enough neutralizer has been drawn off to turn the 

 cream pink the figure opposite the column of neu- 

 tralizer still remaining in the burette indicates the 

 number of c.c. of neutralizer it took to neutralize the 

 cream. 



Each c.c. of neutralizer used shows that there is 

 .1 per cent (one-tenth of one per cent) of acidity in 



