out, well-closed bottle (an India-rubber stopper is
the most convenient), which is then heated in a water oven until
the liquid is clear, no oil bubbles being visible. Phenol-phthalein
solution being added, the excess of potash is estimated by carefully
titrating with standard hydrochloric acid solution.

It was thus found that 1,000 grammes of oil would require 195.5
grammes of caustic potash to convert it entirely into potash soap.

Koettstorfer, to whom this method of analysis is due, gives 191.8, and
Messrs. F. W. and A. F. Stoddart the numbers 191 to 196, as the amounts
of caustic potash required by 1,000 parts of olive oil. The numbers
given by niger seed, cotton seed, and linseed oils are very similar to
these. These oils differ from olive and tea oil, however, in having a
higher specific gravity, and in the property they possess of drying to
a greater or less extent on exposure to air.

(5.) _The Fatty Acids Produced._--A solution of the potash soap was
treated with excess of hydrochloric acid, and after being well washed
with hot water, the cake of fatty acids was dried thoroughly and
weighed. These, insoluble in water, amounted to 93.94 per cent, of the
fat taken. The proportion dissolved in the water used for washing was
estimated by titration with alkali; the quantity of KOH required was
insignificant, equaling 0.71 per cent, of the fat originally used.
This portion was not further examined.

The insoluble fatty acids amounted, as last stated, to 93.94 per cent.
Pure olein, supposing none of the liberated acid to be dissolved in
water, would yield 95.7 per cent. of fatty acid.

The acid was evidently a mixture, and had no definite melting point.
It was solid at 9 deg. C., and sufficiently soft to flow at 12 deg. C.,
but did not entirely liquefy under 22 deg. C. To test its neutralizing
power, 0.9575 gramme dissolved in alcohol was titrated with decinormal
alkali; it required 34.05 c.c. This amount of pure oleic acid would
require 33.95 c.c.; of pure stearic acid, which has almost the same
molecular weight as oleic acid, 33.71 c.c.; or of pure palmitic acid,
37.4 c.c. This, taken in conjunction with the way in which the acid
melted, makes it extremely probable that it is a mixture of oleic and
stearic acids.

Additional evidence of the large proportion of oleic acid was
furnished by forming the lead salt, and treating with ether, in which
lead oleate is soluble, the stearate and palmitate being insolubl