The sample was of a deep brown color, of a fluidity intermediate between olive and castor oil, and possessed a strong, rather disagreeable odor.
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.
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.
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.
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.
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 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.
The insoluble fatty acid amounted to 95.315 per cent. of the oil taken. It was evidently a mixture of two or more fatty acids. On trying to take its melting point, I found that it commenced to soften at 17° C., was distinctly liquid at 19°, but not completely melted until 22° C.
According to O. Bach (Year Book Pharm., 1884, p. 250), the fatty acids from rape seed oil melt at 20.7° C., which is fairly concordant with the result obtained for cabbage oil acids.
The neutralizing power of these acids was then tested. 0.698 gramme dissolved in alcohol required 20.52 c.c. decinormal alkali. It is a singular coincidence that brassic acid (CHO), which is a characteristic acid of colza and rape oils, would have required almost exactly this quantity of alkali for neutralization, O.698 brassic acid theoretically saturating 20.69 c.c. of decinormal alkali. I am disposed to regard this as a coincidence, since a subsequent experiment showed that the lead salts formed were partially soluble in ether, whereas the lead salt of brassic acid is said to be insoluble in this liquid.