Bersch, Josef, 1840-1907, Bersch, Wilhelm, 1868-1918, Salter, Charles · London, Scott, Greenwood, & Son, New York, D. Van Nostrand Company · leaf 64
PREPARATION OF THE COLOUR EARTHS 49 quantities. They will also crush fairly large lumps, and they can therefore be used for the further reduction of materials roughly crushed in a breaker, etc. The material may be treated in either the wet or dry state, only slight alteration being needed to change… … FIG. 5. but all of them can be divided into two groups, viz. : mills with stationary troughs, whilst the shaft carrying the runners rotates; and those in which the trough revolves, and the stones merely turn on the stationary horizontal shaft. Comparison of the efficiency of the two types has shown…
Pigments · Coloring matter
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