The first attempt to manufacture linseed oil in quantities was by the ancient screw and lever press, a modification of the old cider press. It consisted of a barrel, sometimes of cast iron, perforated to give a free outlet to the oil, and fitted with a plunger which, when actuated by the screw, descended into the open barrel upon the mass of meal contained therein, and by means of slow pressure expressed a reasonable amount of oil. This press was worked by a hand lever placed through an eye at the head of the screw, like a bar in a capstan. Little oil was secured, however, in comparison with presses actuated by machinery. On this account considerable oil remained in the dry residue known as oil cake; these weighed about 25 pounds each and were about 18 inches in diameter by 8 inches thick, resem bling a cheese in shape and thus giving to it the name of cheese Box* press. The capacity of this press was less than one barrel of oil a day. The screw and lever press was retained in use as late as 1848. Some years prior to that date, however, the improved Dutch mill or wedge press had come into vogue. These mills were imported from Holland, and were con sidered a great improvement over the old screw and lever presses. The wedge press consisted of a very heavy rectangular frame work of oak or iron, placed horizontally on its base. The ground seed was shoveled by hand into woolen bags and these were hung vertically between hinged partitions, consisting of wooden plates. The capacity of the press was about 9 or 10 of these bags, giving a daily pressing of not over 15 to 20 bushels. The cakes left in this press weighed from 8 to 10 pounds each, after the raw edges had been trimmed. The pressure requisite for the ex pression of the oil was obtained by driving wooden wedges between the plates by means of sledges driven by wind or water power. This press was still in use in 1853.
The wedge press was discarded for the horizontal hydraulic press, the next step in the advancement of the industry and undoubtedly the most important. Probably the first hydrau lic presses used in the United States for linseed oil were those installed in a New York mill shortly after the War of 1812. In these the plates were of iron instead of wood, and mov able; the ground seed was shoveled into the woolen bags as before, flattened by the hand of the workman, and placed in mats of horsehair, which were folded in book form. After plac ing in the press vertically, one at a time, the iron plates were moved up against each bag, when the ram of the hydraulic cylinder moving horizontally compressed the eight or nine cakes contained in the press, the oil running into a trough or pan beneath. The yield of oil was very much increased by this method. The horizontal however, had its disadvan tages, and in 1851 the first patents for vertical hydtaulic presses for linseed oil were granted. The capacity was not increased over the hori zontal type at first, the press holding only 6 to 10 cakes. The clumsy and unwieldy manner
of packing the meal in the bags and filling the presses, however, was done away with. What is known as were used, the ground seed being molded into soft cakes, packed in wrap pers and placed in the press, one above the other, the boxes acting as shelves. A large saving was made here in labor and time, neces sarily resulting in considerable increase of daily capacity and consequent reduction in the cost. With the improvements in the manner of pressing the seed came improvements in grind ing or crushing. Linseed was crushed first in this country by rolling through a mill worked by hand; the rollers in this mill consisted of one large and one small, the seed being passed through once or twice, according to the views of the crusher. The earliest method for reduc ing the linseed to meal by machinery was that used in connection with the Dutch mill or wedge press, and was called the mill. This was a mortar and pestle on a large scale. The mortars were of heavy cast iron, the bottom flat on the inside and holding a small amount of flax seed; the pestle was an iron-shod log, standing vertically in a frame, the foot resting on the bottom of the mortar; these logs, weigh ing from 150 to 200 pounds each, were raised, by means of cams on a horizontal shaft, by water or wind power, and falling of their own weight exerted a crushing or grinding force upon the seed. The tampers, as they were called, numbered one or more in the set. The capacity of a mill was necessarily cut down very much by such a slow process, and rolls run by machinery were resorted to; these were of different design from the old hand rolls, and were designated in the trade as rolls, for the reason that they cracked or opened the seeds. These rolls were arranged in pairs only and varied in size from 12 to 18 inches in diameter and 7 to 18 long, according to the views of the manufacturer. After being bruised in these rolls, the seed was placed in an edge-runner or chaser, also known as a muller. This consisted of a circular trench of iron, several feet in diameter, placed horizon tally on a firm foundation. Running around this, like wagon wheels in a rut, were two ponderous iron-shod wheels, 5 to 6 feet in diameter with steel tires 10 to 16 inches wide. These were sometimes made of stone and set ....site one another on a shaft and weighed a..ut 7,000 pounds each. Around and around these wheels revolved, chasing one another until the meal was finely crushed and rolled, when water was added until the meal acquired the consistency of putty, or what was termed ffdobby.) It was then mixed or for some 10 or 15 minutes and then tempered with heat. These muller stones proved very satisfactory as to results, but were clumsy and took a great deal of power; furthermore, the expense of two grindings was unnecessary. Nevertheless, no change was made for many years.