Since then the hydraulic press has practically completely superseded all other appliances used for expression, and in consequence of this epoch-making invention, assisted as it was later on by the accumulator - invented by William George (later Lord) Armstrong in 1843 - the seed-crushing industry reached a perfection of mechanical detail which soon secured its supremacy for England.
By an hydraulic press a pressure of 100,000 kilos was made to act upon the disks, when the metal was seen to "flow" out of the hole like a viscid liquid.
The arrangement is, in fact, a modification of the plug and feather system used in stone quarrying for obtaining large blocks, but with the substitution of the powerful rending force of the hydraulic press for handpower in driving up the wedges.
At Sunderland, the bridge is first lifted by a hydraulic press so as to clear the roadway behind, and is then rolled back.
The crushed mass is then placed in hempen cloths and pressed in a screw or hydraulic press.
