Knight's American mechanical dictionary : a description of tools, instruments, machines, processes and engineering, history of inventions, general technological vocabulary ; and digest of mechanical appliances in science and the arts . belt is shiftedback to its original pulley by a similar device at theother end of tlie machine. Whitworths (|uick return for shaping-machine(lower figures). A spur-wheel a, revolving freelyupon a large fixed overhanging shaft, is attached toa convenient part of the head. Through, but notconcentric with, the shaft, runs a spindles, having aslotted crank-piece b o
Knight's American mechanical dictionary : a description of tools, instruments, machines, processes and engineering, history of inventions, general technological vocabulary ; and digest of mechanical appliances in science and the arts . belt is shiftedback to its original pulley by a similar device at theother end of tlie machine. Whitworths (|uick return for shaping-machine(lower figures). A spur-wheel a, revolving freelyupon a large fixed overhanging shaft, is attached toa convenient part of the head. Through, but notconcentric with, the shaft, runs a spindles, having aslotted crank-piece b on its extremity, by which it iskept in contact witli the face of the wheel, and con-nected therewitli by a pin engaging in the slot; thevelocity of the crank varies as the pin approaches orrecedes from the center, supjiosing that of the wheelto be uniform. The end of the connecting-rod maybe set at any point in tlie dovetail groove in the laceof the crank-piece, for adjusting the length of See {Metal lurgy.) illustrates tlie furnace employed at Almailen,Spain, for obtaining metallic mercury from shows part of a chain of aludels, B is a vertical rig. Quicksilver-Furnace. longitudinal section, and C a hoiizontal section ofthe furnace, the part x x being in plane. This of two upright cylindrical shafts a n, .separateilby an arched space .e x. Tlie fire is made in theshaft (I, and immediately over it is placed a quan- tity of sandstone containing a small proportion ofcinnabar ; over tliis is laid the richer ore, and theopenings in the shaft are covered with tiles andtiglitly luted. Tlie mercurial vapors evolved are conducted intothe space 6, and thence pass through the rows ofaludels cc, 12 in number and 20 to 22 meters inlength. The metallic vapors condensed in the aludels runinto the gutter d, and are collected in stone cisternscc, while those whiili arc not condensed pass intothe chamber a
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