380 
Beport of the Chemist of the 
age found in the above butters is nearly the same as the mean given 
by Wiley, being 33.7° C, the extremes are much wider, viz., from 30.5 
C. to 36.9° C. This, however, is only true of the butters from single 
cows, as the butters from herds fall nearly within his limits, the aver« 
age being 34 C, ranging from 32.7 C. to 35.3 C. 
These results vary greatly in the butter from individual cows, but 
are not sufficiently marked between the breeds to show that variation 
may be attributed to this cause. They are, however, sufficient to render 
this determination useless for the detection of adulteration. Although 
the Holstein butters are much softer than the Jersey butters when 
exposed to warmth, they do not appear to become liquid at a percep- 
tibly lower temperature. 
5. Viscosity of Solutions of Butter Soaps. 
Aqueous solutions containing 4 or 5 per cent of potash soaps 
become, when rendered slightly alkaline with potassium hydrate, quite 
viscous, and when the amount of free alkali is considerable, are com- 
pletely gelatinized. Each of the fatty acids, stearic, oleic, etc., which 
enter into the composition of fats and oils, forms with potash a soap 
whose aqueous solution has a definite coefficient of viscosity. Solu- 
tions of these soaps behave differently with potash, stearic and oleic 
acid forming soaps whose solutions are more easily gelatinized than 
the soaps of other fatty acids found in ordinary fats and oils. It fol- 
lows that solutions of soap with a definite amount of potash from dif- 
ferent fats will be more viscous in proportion as these acids predom- 
inate in the fats used. The salts of the volatile fatty acids are but little 
influenced by potash. This is also true of palmitic and the other acids 
of butter except oleic and stearic. It is evident, therefore, that the 
determination of viscosity of soap solutions, made under the same 
conditions, furnishes a means of discriminating between different fats 
and oils. Especially is this true when applied to butter and its substi- 
tutes, as those fats used for the adulteration of butter are composed 
almost entirely of glycerides of stearic and oleic acid. A soap made 
from 15 grams of stearic or oleic acid, with 10 gms. of potassium 
hydrate, dissolved in water and made up to 500 cc, will form at 20° C. 
a very viscous solution; it is indeed almost a jelly. Lard, tallow, cot- 
tonseed or olive oil and all of the common fats and oils act in a simi- 
lar way. The same is true of butterine, oleomargarine and all of the 
commercial substitutes of butter. Butter, on the contrary, when 
treated in this way, gives a limpid solution, the viscosity of which is 
very slight. Butters, however, on account of the variation in the 
amount of volatile acids and olein, have a very wide range, so that 
