readily, giving a very soft soda-soap. It dries less rapidly than linseed oil, and is used for mixing paints and making oil-varnishes. It is said to corrode tin plate and even platinum. LINSEED-OIL.--The flax plant, so well known as yielding a textile fibre, affords a valuable oil-seed. The supplies of linseed for crushing are furnished chiefly by Russia and India. It is found that, as a general rule, the colder the climate in which the seed is grown, the greater are the drying properties of the oil, but the worse is its colour. In India, preference is given to white seed, as yielding 2 per cent. more oil, affording it more freely, and giving a softer and sweeter cake, than the red seed; the latter, moreover, always comes to market largely mixed with rape-seed, which is very difficult of separation, and greatly depreciates the market value. Oil from unripe seed is watery. The seed should always be kept for 3-4 months in a dry place, as the oil furnished after this lapse of time is much more abundant than when the expression takes place immediately after the harvest. The seed is crushed and pressed in the manner described on p. 308. The best and finest oil is that which is “cold-drawn”; it is paler, less odorous, and less flavoured, but the yield is only 21-22 per cent. of the seed. By the aid of a temperature not exceeding 200° F., and powerful and long-continued pressure, as much as 28 per cent. of very good oil can be obtained. The cake forms a valuable cattle food. The Italian variety is said to have a much more highly oleaginous seed than the Russian. Linseed-oil has a faint colour, and mild odour and flavour when pure, but the commercial article is dark-yellow, with sharp repulsive flavour and odour. Its sp. gr. is 0·930; at 0° F., a little solid fat separates out; at-4° F., it solidifies. By exposure to the air, after heating with oxide of lead, it rapidly dries up to a transparent varnish. The fresh oil saponifies readily, giving a yellow and very soft soap with soda; by saponification, it yields 95 per cent. of fatty acids, chiefly linoleic, with a little oleic, palmitic, and myristic acids. It dissolves in 1·6 parts of ether, and in 32 parts of alcohol at 0·820 sp. gr. The oil is very extensively used in the manufacture of paint and oil-varnishes. For artists’ use it is purified by shaking up with whiting, and warming. Linseed-oil is never met with in commerce really pure, nor even the seed itself. Previous to the Crimean War, it was a recognised custom at the Black Sea ports to add one measure of hemp or other seed to every 39 of linseed. Since then the proportion has advanced to 1 in 19, in addition to which the Indian seed is grown mostly as a mixed crop with mustard and colza: pure linseed oil can only be obtained by picking out the seeds individually.