1272 



INDEX. 



Page. 

 Ores, concentration of , special factors affecting. 1199-1222 



formation of, by aqueous solutions _ 1058-1234 



by chemical precipitation - - - 1037 



by different processes, transition be- 

 tween - - 1235-1240 



by gaseous solutions, discussion of 1052-1058 



by igneous processes, discussion of 1043-1052 



by mechanical concentration 1038-1039 



by metamorphic processes - 105:.' -l^f- 



by sedimentation- 1037-1043 



metals of , sources of 1235-1240,1069-1072 



Ore shoots, formation of, in secondary frac- 

 tures - - 1228-1229 



frequency of, near complex fractures 1225 



influence of wall rocks on formation of . - - - 1229 



location of, factors determining 1083 



occurrence of, near flexures -- 1225-1226 



origin of some, during late orogenic movements. 1228 



variations in size and richness of. 1223-1224 



Oregon, copper deposits of -- 1055-1056 



Organic matter, importance of, in ore deposition. . . 1146 



oxidation of --- 461-166,606-607 



precipitation of gold by 1094-1095, 1098-1099 



precipitation of ores by 1110-1111 



Orientation of mineral particles in recrystallized 



rocks, discussion of 688-689 



Orogenic movements, ground- water level as effected 



by — -- - — - 426 



ore shoots formed by . 1228 



Orthite, chemical and physical constants of 195 



Orthoclase, alteration of, to kaolin and quartz, vol- 

 ume change produced by 632 



alterations and alteration products of 253-257, 



374,389,398,404 



chemical and physical constants of 199,253 



occurrence of - 253 



sources and modes of formation of 253,266, 



333, 334, 335,371, 376,384, 386,393,397,400,401,408 

 Orthoclase, albite, and anorthite, alterations and 



alteration products of 375,377,389,404 



Orthoclase and gibbsite, alterations and alteration 



products of 389,400 



Orthoclase and mierocline, equation showing pro- 

 duction of muscovite from 1070 



Orthoclase, calcite, and hematite, alterations and 



alteration products of 389, 401 



Orthoclase, magnesite, and siderite, alterations and 



alteration products of 389,401 



Orthoclase, magnesite, siderite, and gibbsite, altera- 

 tions and alteration products of 389 



Orthorhombic pyroxenes, character, occurrence, 



formation, and alterations of 267-271 



Osmotic pressure, character of 72-74 



Osteolite, source and mode of formation of... 356,371,378 

 Ostwald, W., diagram cited from, showing quanti- 

 tative relations between solution and 



temperature . 80 



on acid reaction of solutions containing strong 



acidandweak base 87 



on acids, character of 93 



on acids and bases 84 



on acids and bases, strength of, as a measure of 



reaction capacities.. - 94 



on adsorption 121 



on bases, character of 92 



on carbonic acid, absence of second stage of dis- 

 sociation in 85 



Page. 

 Ostwald, W., on chemical reactions, nature and 



speed of 91 



on crystallization from solutions 75 



on diffusion in solutions 82,83 



on gas absorption by water as affected by solids 



held in solution 72 



on beat phenomena of chemical solutions 106, 107 



on hydrolysis 86,87,108 



on osmotic pressure 73,74 



on precipitation i 115,117-118 



on pressure in gas dissolved in liquid 70 



on separation of salts into their ions 66-67 



on solutions 58,77,79 



on surface tension of water 150 



on temperature, effect of, on solubility 72 



Ottrelite, chemical and physical constants of 199,344 



occurrence and alterations of 345 



Oxidation, alterations produced by 405 



belt of, coincidence of, with belt of weathering. 1142 

 compoimds affected by, in zone of katamor- 



phism 171-172 



definition of 204 



depth and pressure required for reversal of.. 180-181 



depth of 606 



in belt of cementation 164, 165, 166, 604-608 



in belt of weathering 163,461-473 



materials affected by 172 



method of , in zone of katamorphism 161 



of carbonaceous matter, carbon dioxide pro- 

 duced by 972-974 



of inorganic compounds, discussion of 466-469 



of organic compounds, discussion of 461^66 



oxygen for, source of, in zone of katamor- 

 phism 161,163,165 



substances affected by 606 



Oxidation and decai'bonation, alterations produced 



by -,. 405 



Oxidation and desulphidation, alterations produced 



by 406 



Oxidation and hydration, alterations produced by . 404 

 Oxidation and titanation, alterations produced by. 405 

 Oxidation, carbonation, and hydration, discussion 



of. 483-484 



Oxidation, carbonation, dehydration, and desilica- 



tion, alterations produced by 399 



Oxidation, carbonation, hydration, and desilication, 



alterations produced by 399 



Oxidation, decarbonation, and desulphidation, al- 

 terations produced by. 406 



Oxidation, hydration, and decarbonation, altera- 

 tions produced by 406 



Oxidation, hydration, and desulphidation, altera- 

 tions produced by 406 



Oxide order of rocks, deposits forming 842-853 



Oxide ores, genesis of 1125-1128 



Oxides, character, occurrence, formation, and al- 

 terations of -- 217-236,520 



Oxides cementing rocks in belt of cementation, 

 forms and conditions of deposition 



of 622-623 



Oxygen, amount of , in atmosphere 944 



in atmosphere, depletion of, causes of 949-956 



in earth's crust 934,936 



in earth's crust, sea, and atmosphere 948 



in sea salt and sea water — 942,943,944 



sources of - - 944,948-949,956 



work of in metamorphism 60,61,62 



