228 Testing Milk and Its Products. 



The specific gravity of condensed milk may be deter- 

 mined by a method similar to that of McGill. 1 50 gr. 

 of the thoroughly mixed sample are weighed into a 

 tared beaker and washed with warm water into a 250 cc. 

 flask, cooled to 60, filled to the mark and carefully 

 mixed. The specific gravity of this solution (a) is then 

 taken and the original density is calculated by means 

 of the following formula: 



Sp. gr. of condensed milk=-l 



b 5ft 



Concentration. The extent of concentration of con- 

 densed milk may be determined approximately by the 

 formula devised by McGill (loc. cit.) : 

 Concentration (c)-5^ 



fttSi 



where a and designate the solids not fat and specific 

 gravity, respectively, of the condensed milk, and a and 

 s^ the corresponding data for the milk used. If $,= 

 1.030 and a =9 per cent., then c -^- gives the con- 

 centration. 



C. BtTTTER. 



265. Sampling. A four- to eight-ounce sample of 

 butter is melted in a tightly-closed pint fruit jar, 

 shaken vigorously and cooled until the butter is hard- 

 ened, the jar being shaken vigorously at short intorva\s 

 during the cooling so as to keep the water of the butter 

 evenly distributed in the mass. 



266. a. Determination of water. Small pieces of 

 butter (about 2 grams in all) are taken from the sam- 

 ple by means of a steel spatula and placed in glass tubes. 

 seven-eighths of an inch in diameter and two and a half 



1 Bulletin 54, Laboratory Inland Rev. Dept., Ottawa, ( 1 anndn. 



