
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