The SciencesFebruary 1, 1913
The Hardness of Coins
The Blow of the Die Renders the Surface Specially Resistant, While the Interior of the Coin Remains Softer
The Hardness of Coins
The Blow of the Die Renders the Surface Specially Resistant, While the Interior of the Coin Remains Softer
The Extraction of Gold by Chemical Methods
Gold Extraction Processes
Detection of Gold in Dilute Solutions