428 FARM ANIMALS 
amount of butter fat only, in estimating the amount of butter in a 
given sample, it is necessary to add something in addition, to make 
up for the other substances in butter besides butter fat. Butter 
contains, in addition to butter fat, also moisture, salt and other sub- 
stances. To meet the increase, butter is approximately one-sixth 
more than the butter fat contained in the milk or cream. If, for 
instance, 150 pounds of milk showed a fat test of 4 per cent, 
there would be six pounds of butter fat in that quantity; but since 
butter is one-sixth more, the true amount of butter in the 150 pounds 
of milk would be not 6 pounds, but 6 pounds plus 1 pound, or 7 
pounds in all. 
4. (a) Suppose that by deep setting one-half of one per cent of 
fat is left in the skim milk and the skim milk is 80 per cent of the 
total product, what per cent of the fat of the milk is lost, if the 
ae milk contained 3 per cent of fat? If it contained 5 per cent 
of tats 
(b) Suppose that with a cream separator two-hundredths of one 
per cent of fat is left in the skim milk, which is 90 per cent of the 
total product, what per cent of the total fat of the milk is lost if 
the milk contained 3 per cent of fat? Five per cent of fat? 
(c) Suppose a creamery receives an average of 5,000 pounds of 
milk daily for 300 days, how much butter would be lost during the 
period in each of the four cases? 
