The Specific Gravity at 60° Fahr., 914.0.—The specific gravity of rape oil and colza oil, both of which are obtained from species of the genius Brassica, varies from 913.6 to 916.
Exposure to Cold.—This oil by exposure to a temperature of -12° C. (10° F.) becomes solidified in course of an hour, a bright orange-yellow mass resulting.
Qualitative Examination.—The three reagents before indicated were applied to this oil.
(a.) Sulphuric Acid.—The color produced was very marked and characteristic; it differed considerably from any of the others simultaneously tested, the nearest to it being olive end rape oil.
(b.) Strong Nitric Acid.—The reaction was more violent than before, the stratum of oil after cooling being darker in color than in the three cases before mentioned. The reaction with rape oil was similar in all respects.
(c.) Elaidin Test.—The solid mass of elaidin formed was of a darker color than that from olive, almond, and tea oil, but closely resembled that from rape oil.
Free Acidity.—This was estimated as above described. 100 grammes of oil would require 0.125 gramme caustic potash. The samples of rape oil examined by Deering (loc. cit.) were found to require from 0.21 to 0.78 KOH per 100 grammes oil.
Saponification of the Oil.—Upon saponifying with alcoholic potash, it was found that 1,000 grammes of oil required 175.2 grammes of potash for complete saponification.
The number obtained by Koettstorfer for colza was 178.7, by Messrs. Stoddart for rape oil, 175-179, and by Deering for rape oil, 170.8-175.5. The only other oil of which I can find figures resembling these is castor oil, which requires 176-178 grammes per kilo (Messrs. Stoddart). The difference in specific gravity between this (cabbage) oil and castor oil and the solubility of the latter in alcohol point to a wide distinction between them. Hence I think the numbers above given conclusively demonstrate the resemblance between this oil and rape oil in composition.
The Fatty Acids.—The acids produced by adding HCl to the potash soap were almost entirely insoluble in water. The actual amount of potash required to neutralize the acid in the wash water equaled 0.20 per cent. of the oil originally taken.