358 CHEMICAL TESTS AND ANALYSES 



invert the sucrose, determine, the total invert sugar, deduct frpm 

 this the lactose calculated as invert sugar and calculate the 

 difference as sucrose. 



Milk Solids. 



Deduct the per cent sucrose from the per cent total solids. 

 The difference represents the per cent milk solids. 



EVAPORATED MILK. 

 Preparation of Sample. 



Shake the can of evaporated milk vigorously before opening. 

 If, upon opening the can, separated cream or small lumps of 

 butter are found to adhere to the seams and around the junction 

 of the ends and the body, set the can in a water bath at 130 

 degrees F. for ten minutes or until all fat is completely dissolved. 

 Then pour the entire contents into a beaker and pour back and 

 forth several times until a 1 homogeneous mixture is secured. If 

 it is known before opening the can that the contents are sep- 

 arated, submerge the whole can in a water bath at 130 degrees 

 F. for ten minutes, then shake, open and proceed as above. 



If it is desired to use a 40 per cent solution, as directed 

 under the determination of the individual ingredients, weigh 

 accurately 40 grams of the properly mixed contents of the can 

 into a 100 c.c. graduated flask. Add 60 c.c. water and mix thor- 

 oughly by shaking or stirring. 



Specific Gravity. 



Aerometric Method. 



Apparatus. 



Beaume hydrometer. Use a special Beaunie hydrometer 

 with a scale ranging from five to twelve points, graduated to 

 tenths degrees and mercury-weighted. Length over all eleven 

 inches, length of spindle six inches, length of empty bulb four 

 inches and width of empty bulb seven-eighths inch. 



Hydrometer jar. Use a glass or tin cylinder with substantial 

 base. Minimum height ten inches and minimum width one and 

 a half inches. 



Determination. 



The Beaume hydrometer is graduated to read correctly at 

 60 degrees F. (15.5 degrees C.). For every degree Fahrenheit 



