218 Testing Milk and Its Products. 



cooled, and weighed; the fat in the sample is obtained 

 from the difference between this and the preceding 

 weight. The gooch is then carefully heated over direct 

 flame until a light greyish ash is obtained; this operation 

 is preferably done in a muffle oven to avoid possible loss 

 of alkali chlorids. The loss in weight gives the casein in 

 the sample weighed out, and the increase in the weight 

 of the gooch over that of the empty gooch with asbestos, 

 gives the ash (mainly salt) of the butter. The salt in the 

 ash may be dissolved out by hot water, and the chlorin 

 content of the solution determined by means of a stand- 

 ard silver- nitrate solution, using potassium chromate as 

 an indicator. 



269. A practical method of estimating the salt content 

 of butter. A method of estimating the salt content of 

 butter, which is applicable also outside of chemical lab- 

 oratories, has been worked out jointly by Messrs. Alfred 

 Vivian and C. L. Fitch. 1 The salt of the butter is dis- 

 solved in hot water, and a certain portion of the solution 

 when cool is pipetted off and titrated with a silver-nitrate 

 solution prepared by dissolving one silver- nitrate tablet 

 in 50 cc. water, potassium chromate being used as an 

 indicator. The silver nitrate tablets are sold for 60 cents 

 per 100, which number is sufficient to make 100-150 

 tests. The method is advertised in the dairy press under 

 the name of " Fitch's Salt Analysis." Directions for 

 making tests by this method are furnished with the ap- 

 paratus when this is bought. The price of a complete 

 outfit is $4.50. 



1 Wis. Experiment Station, XVII Report, pp. 98-101; Hoard's Dairy- 

 man, February 15, 1901, article: "Uniform Salting of Butter." 



