BUTTER 83 
contents are heated at the temperature of boiling 
water till the weight is constant. 
The fat may also be determined by drying the 
butter on asbestos or sand, and extracting by 
anhydrous alcohol-free ether. After evaporation 
of the ether the extract is heated to constant 
weight at the temperature of boiling water and 
weighed. 
CasEIn, ASH, CHLORIN.—The crucible con- 
taining the residue from the fat determination is 
covered and heated, gently at first, gradually 
raising the temperature to just below redness. 
The cover is removed and the heat continued until 
the material is white. The loss in weight rep- 
resents casein, and the residue mineral matter. 
In this mineral matter dissolved in water slightly 
acidulated with nitric acid, chlorin may be 
determined gravimetrically with silver nitrate, 
or, after neutralization with calcium carbonate, 
volumetrically, using potassium chromate as 
indicator. 
SaL_t.—About 10 grams are weighed in a beaker 
in portions of about 1 gram at a time taken from 
different parts of the sample. Hot water (about 
20 ¢.c.) is now added to the beaker, and after 
the butter has melted, the mass is poured into 
the bulb of a separating funnel, which is then 
closed and shaken for a few moments. After 
standing until the fat has all collected, the water 
