New Yoke Agricultural Experiment Station. 379 
fatty acids of butter are a mixture of oleic, stearic and palmitic, the 
proportion of oleic and stearic acids must be larger in Holstein than 
in Jersey butter. 
Blythe gives the percentage of the different glycerides of butter as 
follows : 
If we consider the stearine and palmitine as present in equal quan- 
tities, the milligrams of potassium hydrate required for saponifying 1 
gm. of this typical butter would be 222.8. This is considerably less 
than the average obtained from pure butters. Assuming stearine as 
absent and replaced entirely by palmitine there would be required 
only 227.6 mgr. potassium hydrate for 1 gm. of fat. This is about the 
average for butter and is considerably less than the highest limit 
found. This would indicate either that the olein of butter has been over- 
estimated, or that there is present in butter glycerides of other fatty 
acids of lower molecular weight than those which have been men- 
tioned, or that stearine in most butters is absent. The iodine numbers 
for the 26 butters in the tables show an average per cent of olein 41.5, 
or very nearly that mentioned by Blythe. 
If we assume that in Reichert's method 75 per cent of the volatile 
fatty acids are recovered, we have a means for calculating approxi- 
mately the composition of these butters. The iodine number gives 
data for obtaining the olein, so that there is left the stearine and pal- 
matine to neutralize the remainder of the potassium hydrate required 
for saponification. An attempt to apportion the K O H remaining 
between stearine and palmatine, shows that in many of these butters 
the potash is in excess even if stearine is absent. This indicates that 
either stearine is present in small quantity or that insoluble acids of 
lower molecular weight than palmatic are present in considerable 
quantity. 
The melting points given for these butters were determined in the 
manner proposed by "Wiley, by means of disks of fat suspended in a 
mixture of alcohol and water and noting the temperature when the 
disks assume a spherical form. Wiley says (Bulletin of Dept. of Agri- 
culture No 13, p. 49) : " The mean melting point of the butters examined 
is 33.8° C, the maximum is 34.7° C, and the minimum 32.6° C. In 
general terms, it may be said that a genuine butter will show a melting 
point falling within the limits of 33 C. and 34 C." Although the aver- 
Olein 
Stearine and palmitine 
Butyrine 
42.2 
50.0 
7.8 
4. Melting Points. 
