New York Agricultural Experiment Station. 381 
small quantities of foreign fats when mixed with butter may not be 
detected. The volatile fatty acids of butter tend in two ways to 
reduce the viscosities of its soap solutions. First through their low 
coefficient of viscosity, and second through their comparatively high 
neutralizing power, which leaves less alkali in solution. 
The tests of the Dairy Show butters show these variations in a most 
satisfactory manner. They indicate clearly breed peculiarities and 
variation in the composition of butter from single cows not shown by 
other methods. The viscosities given are expressed by the number of 
grams of cane sugar, which, dissolved in water and made up to 1 litre, 
give solutions having the same viscosity as the liquid under examina- 
tion. The thoroughbred Holstein butters, 7 in number, have an aver- 
age viscosity of 237, ranging from 112 to 461. Seven thoroughbred 
Jersey butters averaged 74, ranging from 50 to 103. Of other 
thoroughbred butters, the Guernseys are represented by two and 
the Ayrshires by one sample. These are insufficient to show breed 
peculiarities which may exist, and are classed with those from grades 
and unknown sources. The average viscosity of these unknown butters 
is 93, ranging from 65 to 208. 
The general average for all of these butters is 127, ranging from 
50 to 461. This average, however, owing to the large number of 
Holstein butters, is too high. The average for commercial butters 
throughout the country will probably not exceed 100. 
An inspection of the figures shows the viscosities to vary quite 
uniformly with the iodine numbers, or, in other words, with the per- 
centage of olein which the butters contain. Tests with commercial 
oleic acid, probably not pure, show that the quantity of oleic acid 
found in butter by the absorption of iodine, when saponified and 
dissolved in water containing the same amount of free alkali as the 
butter soap solutions, will have nearly the same viscosity as those 
solutions. This indicates that stearic acid is either entirely absent in 
butter, or present in very small quantities ; and fully confirms, in an 
independent manner, the conclusions reached by comparison of the satu- 
ration equivalents of different butters. It is of course possible that the 
volatile and other fatty acids of butter having a low molecular weight 
may modify the viscosities due to oleic and stearic acids, thus render- 
ing the coefficients of viscosity of these acids, taken together, less than 
they would be if alone. This, however, is not probable, as a mixture 
of the fatty acids of butter, so far as they could be obtained, and 
glycerine, in the proportions given by Blythe as existing in butter, 
when saponified, gave a solution whose viscosity was too great to be 
measured by the apparatus, as arranged for butter. 
