An improvement over the intermittent action of the simple hydraulic press was the Anderson continuous action press, appearing in 1905. In this machine the seed, ground or unground, is pressed in a perforated cylinder of hardened steel by a series of revolving screws, the oil dripping from the perforations, and the residue being expelled as dry meal at the farther end of the machine. The seed may be heated to not more than 140°, or pressed cold. The product is of the finest quality, suitable for the best varnishes. The Anderson machine has a capacity of about eight bushels per hour.
While probably four-fifths of the total lin seed oil output of the United States is manu factured in some kind of a press, by what is termed the "old (as above described), the remaining fifth is made by the "new proc ess,'" in which naphtha is used as a solvent of the oil. The seed is first thoroughly crushed as in the old process and is heated, but without any added moisture. In fact the heater is so arranged as to drive off the natural moisture of the seed. The crushed seed is placed ifi a jacketed cylinder called a percolator, 1,000 bushels at a time. Naphtha, heated by passing through a coil feed water heater, is run in on top of the linseed, and steam is let into the percolator jacket to keep up the heat. The naphtha with its content of dissolved oil is drained off from time to time into a con densing tank, where the naphtha Is boiled off, the vapor passing to a cold condenser, and thence back to the naphtha reservoir. The separated oil is carried to an open tank where it is heated and subjected to a vigorous air blast to remove any lingering odor of the naphtha. The operation is continued with each charge of seed for three days. The residue in the percolator is then treated with live steam, and again leached with hot naphtha. This treatment reduces the oil left in the meal to about 15/2 per cent. The product ranks with the best on the market. The plant for this process costs about 25 per cent less than for the old process, and the profits are more than 60 per cent greater.
The Oil and Its Linseed oil as manufactured may be classified under three headings: raw, boiled and refined. Raw linseed oil is the term applied to oil as it comes from the press in its original state. The principal consumer of raw linseed oil is the paint grinder; as it was used as a vehicle for paint hundreds of years ago, so it is used now. Every year millions of gallons are spread on buildings in the form of mixed paints, one concern alone using over 1,500,000 gallons yearly. Every 100 pounds of white lead requires at least 754 gallons. Boiled linseed oil is, as the name denotes, raw oil boiled over a fire, chemicals being added, the object being to increase its drying properties. Many formulas are used by
the different crushers for making boiled oil, the oldest and most reliable, however, containing principally red lead and black oxide of man ganese, the addition of these substances to the heated oil stimulating the linolein and increasing its affinity for oxygen. The uses for boiled oil are many and varied, but it is principally used as the quick drying oil in paints. The refined or varnish oils are many, and there is the great est rivalry to-day among oil manufacturers as to the qualities of their respective varnish oils. Hundreds of thousands of gallons of these oils are used every year. While the different gums used in the manufacture of varnishes are ti-e basis or foundation, some variety of refined oil is the most important component of the varnish. As stated before, raw linseed oil has certain component parts which must be removed and all tendency to must be eliminated. Descriptions, however, of these methods will not be attempted, as they pertain more partic ularly to the chemistry of linseed oil and not to its manufacture. The reliable varnish oils are few and are furnished only by the largest manufacturers. Linseed oil in some form plays a very prominent part in the manufacture of linoleum and oil cloths also. Varnish oils are used in the manufacture of patent leather, for shoes and other purposes, carriage tops, and all kinds of dressed leathers are finished with lin seed oil. The oil clothing worn by sailors and fishermen is soaked with it. It appears by the thousands of gallons before our eyes in the printers' ink on newspapers, and smaller quan tities are used in the manufacture of oil silks. Linseed oil has no value as an edible oil, or as an illuminant or lubricant. While not very large in comparison with other industries, the consumption of linseed oil in the last few years as compared to former years has increased very rapidly, and at the present time the above in dustries consume annually an amount computed at nearly 62,000,000 gallons. The price of lin seed oil is of course governed by the cost of manufacture and principally by the price of seed and cake. The greatest fluctuation experienced in earlier years was in 1867, when oil went from $1 per gallon to $2.03, and in later years, in 1901, when it went from 50 to 82 cents per gal lon. Linseed oil has always been subject to great fluctuations, and it will be seen by aver aging that from 1876 the annual fluctuation has been about 145/2 cents per gallon, the smallest fluctuation known being in 1M3- , when there was only three cents difference in price at any time during the year. On 15 June 1917 the prices in the New York market for five-barrel lots were raw oil, $1.21 pergallon; boiled oil, $122 per $1 gallon; refined oil, $1.23 per gallon.