SUBJECT INDEX 



987 



Oil (cont'd) : 



- in wells, 34, 830, 831, 837-839, 842, 



856, 858, 864, 867, 884 

 Olefins, 889 



Oligoclase, density of, 80 

 Olivine : 



density of -, 80 



elastic moduli of -, 467 

 Olivine diabase, susceptibility of -, 314 

 Olivine gabbro: 



density of -, 80 



susceptibility of -, 313 

 Olsen testing machine, 457 

 Optical systems: 



- in displacement meters, 465, 456, 930 



- in gravimeters, 127, 129, 132, 133, 134 



- in magnetometers, 301, 321, 322, 332, 



334, 342, 357 



- in pendulums, 101, 102, 105, 107, 109, 



111, 112, 115-120 



- in seismographs, 599, 608, 615 



- in torsion balances, 193, 194, 199 

 Ordovician, 46 



vertical velocities in -, 473 

 Ore bodies, location of: 



- by direct and indirect methods, 4, 5 



- by electromagnetic-galvanic meth- 



ods, 30, 31, 50-52, 789-791, 800-809, 

 813, 815 



- by equipotential-line methods, 26, 



50-52, 703-706 



- by gravimeter, 50, 161, 162 



- by magnetic methods, 19, 50-52, 



296, 297, 409-422 



- by potential-droj>-ratio methods, 29, 



751, 754, 756 



- by radioactivity methods, 35, 51-52 



- by resistivity methods, 28, 50-52, 



739-740 



- by seismic methods, 21, 50, 51, 439, 



502, 520 



- by self-potential methods, 25-27 



- by torsion balance, 50-52, 286-292 

 Ore deposits, classification of, 49-51 

 Ores: 



densities of -, 73 

 resistivities of -, 659 

 Orogenic movements, effect on grav- 

 ity, 165 

 vibrations caused by -, 914 

 Orpiment, density of, 78 

 Orsat pipette, 897 

 Orthoclase : 

 density of -«•, 80 

 elastic moduli of -, 467 

 Oscillations (see Free oscillations and 



Forced oscillations) 

 Oscillator, test (see Shaking table) 

 Oscillograph, 21, 30, 115, 457, 494, 496, 

 497, 503, 552, 553, 598-600, 610, 

 614, 651, 758, 762, 898, 940, 943, 954 

 cathode ray -, 30, 651, 652, 759, 760 

 glow-tube -, 116, 496 



Osmotic potential (see Diffusion po- 

 tential) 

 Out-of -phase components: 



- of electromagnetic fields, 31, 32. 



622, 625, 626, 764, 769, 779, 782- 

 797, 800-806 



- of potential fields, 624, 686-690, 692, 



694, 701, 702 



- of radio fields, 653 

 Overburden : 



density of -, 82 



elastic moduli of -, 468, 475 



Rayleigh wave velocity of -, 473 

 Overhang, 35, 862 

 Overshoot, 585, 616 

 Oxidation, 668, 669, 860 

 Oxides, resistivity of, 632, 657 

 Ozokerite, 886, 887 



density of -, 79 



Pallograph, 580 



Paraffin hydrocarbons, 888-892, 895, 896, 



901-905, 909 

 Paramagnetism, 7, 299, 423 

 Partitioning method, 710 

 Peat: 



density of -, 79 



resistivity of -, 637 



specific heat of -, 848 

 Pegmatite, 50 

 Peg models, 378 



Pendulum, 8, 9, 39, 40, 43, 47, 67, 70, 

 97-123 



air-pressure correction for -, 118, 119 



amplitude correction for -, 99, 117, 118 



- apparatus, 108-113 

 Askania -, 110, 111 

 astatic -, 99, 100 

 bronze -, 108, 118 

 Brown -, 110, 112 



coincidence method for -, 10, 103-107 

 companion -, 120 

 fictitious -, 101, 102 



- on fixed support, 97-98 



- support, flexure of, 101, 119-123 



- instrument corrections, 116-123 

 invar -, 108, 118 



inverted -, 10, 99, 100, 113, 127 



isochronous -, 101 



Lejay-Holweck -, 10, 99, 100, 112, 113, 



129 

 mathematical -, 97-98, 580-581 



- measurements in submarines, 101, 



102, 107, 109 

 minimum -, 108 



- on moving support, 101-103 



- observation methods, 103-108 

 operation of -, 103-123 



- period, 10, 97-104, 117-119, 121, 122, 



135 

 physical -, 99 

 quartermeter -, 108 



