ILLINOIS STATE DAIRYMEN'S ASSOCIATION. 109 



process of determining the acid is called an indicator. I have 

 here a solution of this indicator which is called phenolphtalein. 

 On adding a few drops of it to the water in the glass it does 

 change the color of the water. I have here a solution of caustic 

 potash, and on adding a few drops to the contents of the glass 

 changes it to a pink color. If we add a few drops of an acid the 

 pink color disappears and the solution becomes colorless. We 

 find that an indicator is a substance which shows by the color of 

 the solution whether an acid or an alkali is present. (The pro- 

 fessor explained the different parts of the process and the differ- 

 ent chemicals used therein; also a description of the Farrington 

 tablets and their uses.) 



DISCUSSION. 



Mr. Newman: In the Iowa school do you determine the 

 acidity of the cream that is churned every time.'' 



Prof. Weems: Yes. There is more or less trouble for a be- 

 ginner to become accustomed to the method and with the terms 

 used, which are of a chemical nature, but I think a little practice 

 is all that is necessary. 



Mr. Newman: About what percentage do you say is -the best.^ 



Prof. Weems: Our creamery at the college finds that 36-38 

 c. c. of a deci-normal solution of caustic potash for 50 c. c. of 

 cream gives the best results. This result is about .65-. 68 per 

 cent, of lactic acid. Prof. Farrington considers that .6 as giving 

 the most favorable conditions for the production of butter with 

 fine flavor. 



Mr. Pethebridge: Don't you think that it would be a much 

 simpler way to give the acidity in degrees, rather than in centi- 

 meters by means of the burette in exactly the same way.^ 



Prof. Weems: Naturally the simpler the better, but the 

 term cubiccentimeters is one which is used at present very gen- 

 erally in creamery work. I think that the buttermaker should 

 have a knowledge of such terms in order that he may understand 

 the process thoroughly. 



