New York AaricutruraL Experiment STATION. 205 
wellas unjust. The only rational way to compare butters, 
where strict accuracy is required, is to reduce them all to the 
same content of butter-fat, for it is this that gives butter its food 
value, and, other things being equal, its commercial value also. 
: This, of course, involves an accurate analysis of the butter. 
‘ Since butter, on the average, contains, or should contain, 85 per 
cent. of butter-fat, this has been adopted as the standard to be 
used for comparison in this investigation, and all calculations in 
Tables III and IV are based on this standard butter. Thus, the 
i butter in Table IIT, columns VIII, IX and XI, is in every case 
_ butter containing 85 per cent. butter-fat. 
’ The amount of standard butter, or butter containing 85 per 
cent. of butter-fat, is ascertained by calculating from the amounts 
_ of butter given in Table I, column XIII, the composition of which 
is ascertained by analysis, the exact equivalent in butter 
"containing 85 per cent. butter-fat. 
Table IV, containing the “ Percentages of Fat recovered and 
lost,” is derived from data contained in Table III. It states, in 
parts per hundred, what part of the fat in the milk is recovered 
in the cream, and what part is lost in the skim milk; also what 
part of the fat in the milk is lost in the buttermilk, and what is 
recovered inthe butter. If there were no loss of fatin the handling, 
and if analyses were absolutely correct, the numbers in columns IV 
and V, in Table IV, would just equal the corresponding number in 
column II; that is, the fat lost in the buttermilk added to the fat 
recovered in the butter would just equal the fat recovered from 
the milk in the cream. In actual practice, this can not be realized, 
owing to the two possible sources of loss mentioned. The 
“churnability” of fat in milk is the same thing as the “Fat 
recovered in Butter,” in column V, Table IY. 
In Table IV, column VI, the “ Ratio of Fat in Milk to Butter,” 
refers to the amount of butter produced compared with the 
amount of fat in the milk, and is found by dividing the amount of 
butter produced by the amount of fat in the milk of a definite 
quantity of milk, expressing the results on the scale of 100. For 
example, the number of pounds of fat in 100 pounds of a cow’s 
milk is 6.02; from 100 pounds of this milk are made 6.13 pounds 
of butter. The ratio of fat in milk to butter is 6.) 3, divided by 
6.02, multiplied by 100, which gives us the ratio of 102. 
