<i>The World's Gold. A Discussion of the Geological Occurrence of Gold, Its Geographical Distribution, Its Extraction and Methods of Milling, and the Economy of Gold</i> . By L. De Launay, Professor in the École Supérieure des Mines. Cloth; 5½ × 8⅛ ins.; pp. 242. $1.75 net. New York, G. P. Putnam's Sons.
Science