Free use has been made of published literature on the subject, so far as it has been available to the Author. The source of all contributions is acknowledged in the footnotes, but special acknowledgment should be made to the works of Hofman (Metallurgy of Lead, 2nd edition, New York, 1893) and Schnabel (Handbuch der Metallhüttenkunde, Berlin, 1894), to the Engineering and Mining Journal of New York, the Transactions of the American Institution of Mining Engineers, the Columbia College School of Mines Quarterly, and the Berg- und Hüttenmännische Zeitung; also to those friends who have supplied statistical information, and to many gentlemen in charge of metallurgical works, who, although personally strangers, have very kindly afforded the Author most valuable assistance. Errors may have crept in, partly owing to the exigencies of a busy professional life, partly through the Author's absence from civilisation, which rendered it impossible for him to read all the proof-sheets. For all such shortcomings, he begs indulgent consideration at the hands of those who may have occasion to read or consult these pages. MINA DE STA FE, HENRY F. COLLINS. |