1873. GOULD (769).--A curious engine with horizontal shaft having a circular disc at the lower end, fitted with knives on the under-surface, which are in contact with fixed knives lying at the bottom of the vessel. The circulation of the pulp is effected by the centrifugal force generated. 1873. MARTIN (3751).--A beating engine with two rolls in the same trough, the first roll working in conjunction with a smooth surfaced beating roll, the other being in contact with a bedplate of the usual type, the object of the first roll being to partially disintegrate the material without danger of choking. 1874. JOHNSTONE (3708).--A pulping engine in which the rubbing action of two grindstones one upon the other is utilised as a means of beating. 1876. GARDNER (307).--A beating engine in which the beater roll is conical in shape, working vertically in contact with the bottom of the beating engine, which is also conical in shape, the engine itself being circular. 1878. COOKE AND HIBBERT (4068).--The bedplate constructed in the form of a circular segment with a much larger face than usual, and capable of adjustment, the beater roll itself being fixed in the bearings. 1880. FORBES (692).--A long oval shaped beating engine divided into three channels instead of two. In the two outer channels are placed beater rolls and drum washers. The stuff discharged over the backfalls from the two beating engines flows down the central channel and is circulated by a special paddle constructed in such a manner as to deliver the pulp in two equal streams into the outer channels to each of the beater rolls. 1880. UMPHERSTON (1150).--An engine constructed with a passage below the backfall so that the stuff circulates in a trough underneath the beater roll, the object being to ensure more effective treatment and to save floor space. 1883. AITCHISON (5381).--A beating engine of usual form, but with the beater roll made conical in shape with the larger circumference outwards, and the bedplate placed on an incline parallel with the knives on the beater roll. 1884. MAYFIELD (2028).--The backfall of the beating engine is of entirely different construction to the ordinary machine, for the purpose of improving the circulation. 1884. HOYT (11177).--An engine resembling the Umpherston, but with a larger roll, the diameter of which is equal to the full depth of the engine, the backfall being in a line with the axis of the beater roll. 1885. JORDAN (7156).--Additions to the Jordan engine for admitting water and steam to the engine as required. 1885. KORSCHILGEN (9433).--The beater roll made of stone or of metal with a stone casing furnished with ribs or knives placed close together. 1886. HIBBERT (4237).--A beating engine fitted with an ordinary beater roll, and having in addition a heavy disc rotating vertically, the disc being fitted with knives on one surface which rotate in contact with knives fixed on a stationary disc.