A supplement to Ures Dictionary of Arts, Manufactures, and Mines, : containing a clear exposition of their principles and practice. . ter of the stuff to be reduced. The pulverization is said to begreatly facilitated by having four heads in the same chest or cofer, about 24^ inches head is lifted separately, and the cams by which this is done are so disposed on theaxle as to make the blows in regular succession. Great care is also taken whether it be ina large or small battery, to prevent any two pestles falling at the same instant; the objectbeing to secure an equal strain against
A supplement to Ures Dictionary of Arts, Manufactures, and Mines, : containing a clear exposition of their principles and practice. . ter of the stuff to be reduced. The pulverization is said to begreatly facilitated by having four heads in the same chest or cofer, about 24^ inches head is lifted separately, and the cams by which this is done are so disposed on theaxle as to make the blows in regular succession. Great care is also taken whether it be ina large or small battery, to prevent any two pestles falling at the same instant; the objectbeing to secure an equal strain against the power. Practical dressers are not well decidedas to the order in which the lifting of four heads in one cofer should take place, whetherone of the inner pestles should precede the other, or whether a side pestle should be firstlifted. A preference, however, seems to be given to the following method:—supposing aspectator to stand in front of a 4-head stamps, left side pestle first, right side second, rightmiddle third, left middle last. Fig. 482 represents the elevation of a steam stamps employed in Cornwall, a, axle ; 482. n, cams for lifting heads ; c, tongue or projection on lifter; D D, guides for retaining lifter;E, the lifter ; f, he;id or pestle ; g, chest or cofer ; ii, hopper ; j, pass connecting cofer andhopper ; k, launder discharging water into the cofer ; l, stamps grate ; m, launder receivingthe stuff which has been flushed through the grates; n, the bottom or bed of stamps. The stamping process is not so simple as it may appear at first sight. Many of its par-ticulars, such as the form of the cofer, mode of exit for the stuff, weight and rapidity of thepestles, and quantity of water employed, must be varied to suit the mode of disseminationand the structure and character of the ore, as well as of the matrix. Fineness of retiuctionis l)y no means always a desideratum, for if some kinds of stuff be reduced too low, muchof the ore contained in it will be
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Keywords: ., bookcentury1800, bookdecade1860, bookpublishernewyo, bookyear1864
