Formation of, [17];

Origin of, [50], [53-58]

[O]

Ore Deposits, Le Conte’s conclusions as to, [36], [37]

Ore reserves, Calculation of, [168-170]

Ore values, Estimating, [170]

Organic matter as a precipitant of gold, [51], [52], [53]

Otto engines, [110], [111]

[P]

Percussion tables, [88]