| http://www.w3.org/ns/prov#value | - Having described some of the jigs for separating coal from its impurities, before proceeding to a description of other forms of apparatus for the same purpose, but operating in a different manner, a little attention will be given to the auxiliary ma- chinery for crushing, sizing, and transporting the coal and slate in the washing establishment, and for furnishing the nec- essary supply of water.
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