DILUTION-LAW 255 



In five hundred cubic centimeters of N/10 KOH were dissolved 

 62.5 grams of casein, thus forming a solution of potassium casein- 

 ate, neutral to phenolphthalein. To 50 cc. portions of this 

 solution were added, respectively, 0, 20, 40, etc., cubic centi- 

 meters of alcohol, and the mixtures were diluted to 200 cc. with 

 water. Each of these solutions was then diluted, by the addition 

 of alcohol of the same concentration, to the desired concentra- 

 tions of casein. All alcohol percentages are percentages of 99.8 

 per cent alcohol by volume. The solutions in "75 per cent 

 alcohol" were made up by adding 99.8 per cent alcohol to 50 cc. 

 of the original solution of caseinate until the volume was 200 cc, 

 and diluting with a 75 per cent by volume solution of 99.8 per 

 cent alcohol. The conductivity determinations were made at 

 30° C. The conductivity of the distilled water (= 4 X 10-«) 

 has been subtracted from each of the tabulated conductivities. 

 The results are given in Table I on the following page. 



Applying the above equation to these results and computing 



,, , , 1.037 X 10-2 1 075 X 10-5 



the constants — - — , — r— and —^r- — ; — — for each concen- 



p{u + V) pK {u + vY 



tration of alcohol from all of the results by the method of least 

 squares, we obtain: 



For the solutions containing per cent of alcohol : 



m = 12.41 X + 1666 x\ (ii) 



For the solutions containing 10 per cent of alcohol: 



m = 15.97 X + 3325 x"". (ill) 



For the solutions containing 20 per cent of alcohol : 



w = 21.14 X + 5880 x^. (iv) 



For the solutions containing 30 per cent of alcohol : 



m = 27.23 X + 10,858 x\ (v) 



For the solutions containing 40 per cent of alcohol: 



m = 34.63 X + 18,931 x\ (vi) 



For the solutions containing 50 per cent of alcohol: 



m = 42.91 X + 35,937x2. (vii) 



For the solutions containing 60 per cent of alcohol: 



m = 53.49 X + 78,335 x\ (viii) 



For the solutions containing 75 per cent of alcohol : 



m = 29.95 X -\- 1,219,800 x\ (ix) 



