358 CuHemicaL, TEsrs AND ANALYSES 
invert the sucrose, determine, the total invert sugar, deduct from 
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 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. graduated Hask. Add 60 c.c. water and mix thor- 
oughly by shaking or stirring. 
Specific Gravity. 
Aerometric Method. 
Apparatus. 
Beaumé hydrometer.—Use a special Beaumé 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 Beaumé hydrometer is graduated to read correctly at 
60 degrees F. (15.5 degrees C.). For every degree Fahrenheit 
