CHAPTER V.
ASSAY OF ORES.--When an Ore will Pay--Washing for Gold and
Platinum--How to Assay Gold in the Simplest Way--To Test any Rock
for Gold and Silver--To Find the Purity of Gold--To Detect and Assay
Silver Ores--Assay of Copper, Iron, Zinc, Tin and Lead Ores-Ready
Method of Testing Graphite.....92
Underground Treasures: How and Where to Find Them A Key for the Ready Determination of All the Useful Minerals Within the United States · 第 5 / 9 章