ANALYTICAL PKOBLEMS. 



381 



The Solution of Analytical Problems. A dairy chemist is 

 frequently called upon to solve the most diverse problems with 

 regard to milk and its products. In the following paragraphs 

 a few such problems are given, together with the analytical 

 data from which the solution was deduced. They cover a fairly 

 wide range, and may be taken as fairly representative of the 

 questions a dairy chemist is called upon to elucidate. All are 

 actual examples. 



PROBLEM I. To determine to what the low specific gravity of 

 the milk is due. 



Example a. The analytical figures were : 



Specific gravity, 

 Total solids, 

 Fat, . 

 Ash, . 

 Solids not fat, 



1-0234 



9-82 per cent. 



3-21 



0-51 



6-61 



From the extreme lowness of all the figures it was concluded 

 that 26 per cent, of added water was present. 

 Example b. The analytical figures were : 



Specific gravity, 

 Total solids, 

 Fat. . 

 Ash, . 

 Solids not fat, 



1-0300 



1 1 -46 per cent. 

 3-33 

 0-68 

 8-13 



In this case it was concluded from the low solids not fat, and 

 the correspondingly low ash, that a small amount (5 per cent.) 

 of added water was present. 



Example c. Two samples of milk taken from two churns 

 arriving at a station from a farm. 



The analytical figures were : 



Specific gravity, 

 Total solids, 

 Fat, . 

 Ash, . 

 Solids not fat, 



No. l. 

 1-0234 



9-19 per cent. 

 2-67 

 0-55 

 6-52 



No, 2, 

 1-0298 



11-61 per cent. 

 3-30 

 0-69 

 8-31 



In this case analyses of milk from the same farm had been 

 made for some time previous, and the solids not fat had not 

 been found to fall below 8-6 per cent. It was concluded that 

 No. 1 contained 24 per cent, and No. 2 3 per cent, of added 

 water. The conclusion about No. 2 would not have been justified 

 had there not been evidence of the normal composition of this 

 milk. 



