COLZA OIL is a non-drying oil obtained from the seeds of Brassica Napus, var. olelfera, a variety of the plant which produces Swedish turnips. Colza is extensively cultivated in France, Belgium, Holland, and Germany; and, especially in the first-named country, the expression of the oil is an important industry. In commerce colza is classed with rape oil, to which both in source and properties it is very closely allied. It is a comparatively inodorous oil of a yellow colour, having a specific gravity at 60° Fahr, of 0*9128; and it solidifies at 22° Fahr. The cake left after expression of the oil is a valuable feeding substance for cattle. Colza oil is extensively used as a lubricant for machinery, and for burning in lamps. It was for many years employed in British light-houses, having been favourably reported on for that purpose in 1845 by Professor Faraday, but mineral oils are now more generally used.