


339 
to 500 c.c. The vicosity of these solutions, tested with the 
viscometer described in another portion of this report, was 
for the butter fat 65, and for the neutral lard over 500. 
This marked difference was a surprise and naturally led 
to a series of careful tests to determine whether in mixture 
of the two fats the viscosity would be proportional to the 
quantities taken. First the above experiment was repeated 
with butter fat, neutral lard and oleo-oil, 20 grams of each 
being taken, and, to avoid a large excess of alkali, only 6 
grams of caustic potash were added to each. They were 
saponified by heating upon a water bath with 20 c.c. of alco- 
hol, the heating being continued till the alcohol was driven 
off. The soaps were dissolved in water and made up to 500 
c.c: The viscocity of these solutions at 20°C. was for the 
butter fat 62, neutral lard 70, oleo-oil 68 or practically the 
same for each. On the supposition that the difference in 
the first case was due to an excess of alkali, the tests were 
repeated with seven, eight and nine grams of caustic potash 
the other details of the experiment being the same as before, 
without any marked difference being found i the viscosity 
of the solutions from the different fats. With 10 grams of 
caustic potash the soaps from the neutral lard and oleo-oil 
were quite viscous, while that from butter fat was only 
slightly changed. The addition of more alkali was found 
to increase the viscosity of the soaps from neutral lard and 
oleo-oil quite rapidly, while that of the butter remained 
nearly the same till about 15 grams of caustic potash were 
used for 20 grams of fat, and was not extremely viscous 
when 20 grams of potash were used. 
The results given below are the average of several deter- 
minations, but are only approximate as they were obtained 
with an instrument not properly adjusted. They do, how- 
ever, show the relative viscosity for the different fats. 
Amount of caustic potash used, grams 7 8 FeO 18 15 16 18 28 
Butter soap, viscosity.......2...-.:4.. 60 66 67 78 85 114 162 252 
Oleo-oil ‘ Raeewe. gp Motes! < Sto ieee 72 102 108 474 too viscous to test. 
Nentral lard soap, viscosity ..:...... 88 89 130 = 480 et ee A 
Sesame oil 33 a A se oe eae nee a 276 
These results were entirely satisfactory and indicated that 
the difference in the viscosity of solutions of soap made 
from butter fat and from those fats generally used for 
butter adulteration could be increased to any desired extent 
by the addition of alkali. 
These tests were followed by a large number of examina- 
of adulterated butters, and of the fats and oils which are 
used for this purpose. The samples examined were ob- 
tained both from the general markets and from the leading 
factories throughout the country. In every instance the 
soaps from the adulterated samples greatly exceeded in vis- 
cosity those from butter fats, when from 10 to 15 grams of 
caustic potash were used for saponification. 
