OILS 



439 



The weight of tho stampers is usually from 500 to 600 Ibs. ; and the height from 

 which they fall upon the wedges is from 16 to 21 inches. 



Such a mill as that now described can produce a pressure of from 50 to 75 tons 

 upon each cake of the following dimensions: 8 inches in the broader base, 7 inches 

 in the narrower, 18 inches in the height; altogether nearly 140 square inches in sur- 

 face, and about f of an inch thick. 



The seeds which have been burst between the rolls, or in the mortars of the Dutch 

 mills, are to be spread as equally as possible, by a shovel, upon tho circular path of 

 the edge-stones, and in about half an hour the charge will be sufficiently ground into a 

 paste. This should be put directly into the press, when fine cold-drawn oil is wanted. 

 But in general the paste is heated before being subjected to the pressure. The pressed 

 cake is again thrown under the edge-stones, and, after being ground the second time, 

 should be exposed to a heat of 212 Fahr., in a proper pan, called a steam-kettle, before 

 being subjected to the second and final pressure in the woollen bags and hair-cloths. 



Fig. 1574 is a vertical section of the steam-kettle of Hallette, and jiff. 1575 is a view 

 of the seed-stirrer. a, is the wall of masonry, upon which, and the iron pillar b, the 

 pan is supported. It is enclosed in a jacket, for admitting steam into the intermediate 

 space d, d, d, at its sides and bottom ; c, is the middle of the pan in which the shaft of 

 the stirrer is planted upright, resting by its lower end in the step e ; f, is an opening, 

 by which the contents of the pan may be emptied ; g, is an orifice into which the 

 mouth of the hair or worsted bag is inserted, in order to receive the heated seed, when 

 it is turned out by the rotation of the stirrer and the withdrawal of the plug /from 

 the discharge aperture ; h, is the steam induction pipe ; and i, the eduction-pipe, which 

 serves also to run off the condensed water. 



When, in the course of a few minutes, the bruised seeds are sufficiently heated in 

 the pans, the double door /is withdrawn, and they are received in the bags below the 

 aperture g. These bags are made of strong twilled woollen cloth, woven on purpose. 

 They are then wrapped in a hair-cloth, lined with leather. 



The hydraulic oil-press is generally double : that is, it has two vertical rams placed 

 parallel to each other, so that while one side is under pressure, the other side is being 

 discharged. The bags of heated seed-paste or meal are put into cast-iron cases, 

 which are piled over each other to the 1574- 



number of 6 or 8, upon the press-sill, 

 and subjected to a force of 300 or 400 

 tons, by pumps worked with a steam- 

 engine. The first pump has usually 2 

 or 2^- inches diameter for a ram of 10 

 inches, and the second pump 1 inch. 

 Each side of the press, in a well-going 

 establishment, should work 38 Ibs. of 

 seed-flour every 5 minutes. Such a 

 press will do 70 quarters of linseed in ^ mj . 

 the clays' work of one week, with the "~ 

 labour of one man at 20s. and three 

 boys at 5s each ; and will require a 

 12-horse power to work it well, along 

 with the rolls and the edge-stones. 



The apparatus for heating the seeds 

 by naked fire, as used in Maudsley and 

 Field's excellent seed-crushing mills, on 

 the wedge or Dutch plan, is represented 

 in the^s. 1576, 1577, 1578, and 1579. 



Fig. 1576 is an elevation or side view 

 of tho fire-place of a naked heater ; 

 fig. 1577 is a plan, in the line uu of 

 Jig. 1576. Fig. 1578 is an elevation 

 and section parallel to the line v v of 

 fig. 1577. Fig. 1579 is a plan of the furnace, taken above the grate of the fire-place. 



A, fire-place shut at top by the cast-iron plate B ; called the fire-plate. 



c, iron ring-pan, resting on the plate B, for holding the seeds, which is kept in its 

 place by the pins or bolts a. 



D, funnels, Britcken, into -which by pulling the ring-case c, by the handles b b, the 

 seeds are made to fall, from which they pass into bags suspended to the hooks c. 



B. Jig. 1578, the stirrer, which prevents the seeds from being burned by continued 

 contact with the hot plate. It is attached by a turning-joint to the collar F, which 

 turns with the shaft o, and slides up and down upon it. H, a bevel wheel, in gear with 

 the bevel wheel i. and giving motion to the shaft G. 



