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A PRACTICAL TREATISE FOR PROSPECTORS, MINERS, AND STUDENTS. By J. C. F. Johnson, F. G. S., MEMBER OF THE AUST. INST. OF MINING ENGINEERS; AUTHOR OF "PRACTICAL MINING," "THE GENESIOLOGY OF GOLD," ETC. PREPARER'S NOTE This text was prepared from a 1898 edition, published by Charles Griffin & Company, Limited; Exeter Street, Strand, London. It is the second edition, revised. Numerous drawings and diagrams have been omitted. CONTEN