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 . rig corresponds to thatof a cutter, excepting a snuiU inizzen in the .stern. /. A weighted line with several hooks, set backto ba<k, dropped into the water, and suddenly jerkedupward to catch fish. 4. (Ioopcriufi.) A drawing-knife with a hollow-ing blade. 5. (Leather.) A machine for graining moroccoleather, consisting of grooved boxwood rollers fittedin a fra
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 . rig corresponds to thatof a cutter, excepting a snuiU inizzen in the .stern. /. A weighted line with several hooks, set backto ba<k, dropped into the water, and suddenly jerkedupward to catch fish. 4. (Ioopcriufi.) A drawing-knife with a hollow-ing blade. 5. (Leather.) A machine for graining moroccoleather, consisting of grooved boxwood rollers fittedin a frame susijended from the ceiling, and swungbackward and forward like a pendulum. 6. (Metallurgy.) A riildle or sieve shaken verti-cally in water, to sejiarate the contained ore intostrata, according to weight ami conseiiuent richness. The ancient Iberians washed gold-bearing earth inbaskets in the time of Strabo. The sieve a commonly consists of a hoop with han-dles, and a bottom ol sheet-brass, finely is used by striking it sipuirely upon the water, amigiving it a semi-rotation simultaneously, to sort tliepulverized ore according to gravity ; the ore beinglifted by the incoming water from below, and the Fig. Jigger and Ji^gin^-Machim. heavier portions settling first. The lighter portionsare scraped from the top, and the lower stratum re-moved for smelting or farther concentration. The object is to keej) the particdes suspended fora short time in water, so as to give the heavier por-tions a cham-e, by rapid subsidence, to arrange them-selves as the lower strata in the sieve ; the finestportions pass through the , settle in tlie vat,and are subsequently washed in a buddlc. JIGGER-KNIFE. 1215 JIM-CROW. Several applicatious of machinery to this be noticed. In one (6) a lieavy sieve is troni a lever,wliicli has a horizontal roller for a rocking axis. Tiielever is worked by a man, who, by a saltatory mo-tion, alternately lifts the j
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