438 



OILS 



centre of the bed, where it is perforated for the passage of the strong vertical shaft 

 which turns the stones, is enclosed by a circular box of cast iron, firmly bolted to the 

 bedstone, and furnished with a cover. This box serves to prevent any seeds or powder 

 getting into the step or socket, and obstructing the movement. The circumference of 

 the mill-bed is formed of an upright rim of oak-plank, bound with iron. There is a 

 rectangular notch left in the edge of the bed and corresponding part of the rim, which 

 is usually closed with a slide-plate, and is opened only at the end of the operation, to 

 let the pasty seed-cake be turned out by the oblique arm of the bottom scraper. The 

 two parallel stones, which are set near each other, and travel round their circular path 

 upon the bed, grind the seeds not merely by their weight, of three tons each, but also 

 by a rubbing motion, or attrition ; because their periphery being not conical, but 

 cylindrical, by its rolling upon a plane surface, must at every instant turn round with 

 friction upon their resting-points. Strong cast-iron boxes are bolted upon the centre 

 of the stones, which by means of screw clamps seize firmly the horizontal shafts that 

 traverse and drive them, by passing into a slit-groove the vertical turning-shaft. This 

 groove is lined with strong plates of steel, which wear rapidly by the friction, aud 

 need to be frequently renewed. 



The following are drawings of the wedge or Butch seed-crushing machines. 

 Fig. 1 570, front elevation of the wedge seed-crushing machine, or wedge-press. Fig. 

 1571, section in the line x x of fig. 1572. 



1572 



1573 



Fig. 1572, horizontal section in the line Y T, of fig. 1571. 



A, A, upright guides, or framework of wood. 



B, B, side guide-rails. 



^ D, driving stamper of wood, which presses out the oil; c, spring stamper, or re- 

 lieving wedge, to permit the bag to be taken out when sufficiently pressed. E is the 

 lifting shaft, having rollers, b,b,b,b,fig. 1571, which lift the stampers by the cams, 

 a a, fig. 1571. F is the shaft from the power-engine, on which the lifters are fixed. 



G is the cast-iron press-box, in which the bags of seed are placed for pressure late- 

 rally by the force of the wedge. 



o, Jys. 1569 and 1573 ; the spring, or relieving wedge. 



e, lighter rail ; d, lifting-rope to ditto. 



/,/,/, flooring overhead. 



g,figs. 1570, and 1573 ; the back iron, or end-plate minutely perforated. 



A, the horse-hair bags (called hairs), 

 containing the flannel bag, charged with 

 seed ; i, the dam-block ; m, the spring 

 wedge. 



Fig, 1572. A, upright guides; c and D, 

 spring and driving stampers; E, lifting 

 roller; F, lifting-shaft; a, a, cams of 

 stampers. 



Fig. 1573, a view of one set of the 

 wedge-boxes, or presses, supposing the 

 front of them to be removed : o, driving 

 wedge ; g, back iron ; h, hairs ; i, dam- 

 block ; fc, speering or oblique block, be- 

 tween the two stampers; I, ditto; '/;, 

 ditto ; m, spring wedge. 

 The first pressure requires only a dozen blows of the stamper, after which the pouches 

 are left alone for a few minutes till the oil has had time to flow out; in which in- 

 terval the workmen prepare fresh bags. The former arc then unlocked, by making 

 the stamper fall upon the loosening wedge or key, m. 



