None
H20 0-61 3-17 Fe203 0-40 0-21 SiO., 0-25 0-50 A1263 . 0-20 Bi0 23 CuO MnO MgO Na0 As203 Insoluble 0-75 0-17 0-09 0-17 0-31 0-06 0-19 2-34 The following list comprises the more important radio-active minerals, with their approximate chemical composition and some notes on their occurrence and probable origin. * Hillebrand, Am. J. Sci. 40, 384 (1890) ; ibid. 42, 390 (1891). APPENDIX B 557 Name Uraninite Cleveite Broggerite Nivenite Pitchblende Gummite Uranophane Uranotil Carnotite Uranosphaerite Torbernite Cuprouranite Autunite Calciouranite Uranocircite Phosphuranylite Zunerite Uranospinite Walpurgite Thorogummite Thorite Orangite Uranothorite Thorianite Composition Oxides of uranium and lead. Usually contains thorium, other rare earths and helium Uranium 50—80% Thorium 0— 10% (Pb, Ca)U3Si012.6H20? Uranium 50— 65% CaO . 2UO3 . 2Si02 . 6H20 Uranium 44 — 56% A vanadate of uranium and potassium Uranium 42 — 51% Bi2O3.2U03.3H20 Uranium 41% CuO . 2U03 . P205 . 8H20 Uranium 44—51% Ca0.2U03.P2Ofi.8H20 Uranium 45 — 51% Ba0.2UO3.P206.8H20 Uranium 46°/0 3U03.P205.6H20 Uranium 58— 64% CuO . 2U03 . As205 . 8H20 Uranium 46% CaO.2U03.As205. 8H20 Uranium 49°/0 5Bi2O3. 3U03 . As205 . 12H20 Uranium 16% U03 . 3Th02 . 3Si02 . 6H20 ? Uranium 41% ThSi04 Uranium 1 — 10% Thorium oxide 48— 71% Oxide of thorium, uranium, the rare earths and lead. Con- tains a relatively large pro- portion of helium. Uranium 9— 10% Thorium oxide 73 — 77% Eemarks Occurs primary as a constituent of rocks and secondary in veins with metalliferous sulphides An alteration product of uraninite. Formed by the action of percolating waters An alteration product of uraninite through gummitei Occurs as a secondary mineral impregnating a porous, sedimentary sand- stone. Found in Colorado and Utah Alteration product of other uranium minerals A variety of gurnmite A primary constituent of pegmatite dikes Occurs as a primary con- stituent of a pegmatite dike in Ceylon. Geological age probably Archean 558 APPENDIX B Name Samarskite Fergusonite Euxenite Monazite Composition Eemarks Niobate and tantalate of Primary constituent of rare earths pegmatite dikes Uranium 8— 10% Metaniobate and tantalate „ of rare earths Uranium 1 — 6°/0 Niobate and titanate of „ „ rare earths Uranium 3 — 10°/0 Phosphate of the rare „ earths, chiefly cerium Uranium 0*3 — 0'4°/ INDEX. The numbers refer to the pages. a rays discovery of, 141 nature of, 141 magnetic deviation of, 142 et seq. electrostatic deviation of, 146 velocity of, 148 value of e/m for, 148 charge carried by, 151 et seq. number of a particles expelled from one gram of radium, 155 mass and energy of, 156. origin of, in atomic disintegration, 157 scintillations produced by, 158 et seq. absorption of, by matter, 161 et seq. increase of absorption with thickness of matter traversed, 163 relative absorption of a rays from radio-elements, 164 absorption of, by gases, 165 et seq. connection between absorption and density, 169 relation between ionization and ab- sorption, 170 theory of absorption of, 170 et seq. range of ionization of, 172 et seq. complexity of a rays from radium, 174 et seq. effect of thickness of layer of radiating matter on emission of, 195 relative ionization produced by a and j8 rays, 196 et seq. phosphorescence by a rays, 202 et seq. connection of, with radio-active changes, 235, 444 et seq., 455 from the emanations, 263 emission of energy from radio-elements in form of a rays, 419 et seq. connection of heat emission of radium with a rays, 421 et seq. number of ions produced by an a particle, 433 absence of, in rayless changes, 454 emission from active products, 454 et seq. loss of weight due to expulsion of, 473 a rays (cont.) a particles consist of helium, 479 et seq. magnetic deflection of, from radium C, 543 velocity and e/m for, from radium C, 543 et seq. diminution of velocity of, in passing through matter, 545 diminution in velocity of, in passing through aluminium, 545 velocity of, when ionization ceases, 545 et seq. connection of phosphorescent, pho- tographic, and ionization effects produced by, 546 et seq. energy required to produce an ion by a rays, 551 Abraham apparent mass of moving charged body, 71, 127 Absorption law of, in gases, 64 et seq. relative absorption of a, /3 and 7 rays by matter, 111 connection between absorption and ionization, 134 et seq., 170 et seq. of /3 rays by solids, 134 et seq. connection between absorption and density for /3 rays, 137 of j3 rays in radio-active matter, 140 of a rays by solids, 161 et seq. of a rays in gases, 167, 170 et seq. connection between absorption and density for a rays, 169 theory of, 170 et seq. of 7 rays by solids, 179 et seq. connection between absorption and density for 7 rays, 181 of rays from the emanations, 263 of penetrating rays from the earth, 520, 540 Actinium methods of separation of, 20 et seq. properties of, 21 similarity to "emanating substance" of Giesel, 21 560 INDEX Actinium (cont.) possible connection with radio-activity of thorium, 28 emanation from, 249 excited activity produced by, 311 effect of magnetic field on excited activity from, 324 separation of actinium X, 365 decay of actinium X, 365 source of actinium emanation, 365 analysis of active deposit of, 366 radiations from products of, 368 penetrating power of p and 7 rays from, 368 products of, 369 table of products of, 449 possible origin of, 464 Actinium A separation and period of, 367 et seq. Actinium B period of, 368 properties of, 368 Actinium X separation and decay of, 364 et seq. production of emanation by, 365 Adams decay of activity of emanation from well water, 511 decay of excited activity from the emanation, 511 Age of radium, 457 of sun and earth. 492 et seq. Allan, S. J. increase with time of excited activity from atmosphere, 505 radio -activity of snow, 506 effect of conditions on decay of activity from air, 519, 523 Allan and Rutherford decay of excited activity from the atmosphere, 503 ionization of air in closed vessels, 534 Allen, H. S. and Lord Blythswood radium emanation in Bath springs, 513 Anderson and Hardy action of radium rays on the eye, 217 Armstrong and Lowry radio-activity and phosphorescence, 444 Arnold rays from phosphorescent substances, 4 Aschkinass and Caspari action of radium rays on microbes, 216 Atmosphere excited activity from, 501 et seq. radio-activity of, due to emanations, 504 Atmosphere (cont.) diffusion of emanations into, from the earth, 507 effect of temperature, pressure, &c. on radio-activity of, 517 et seq. presence of very penetrating radiation in, 520 comparison of radio-activity of, with radio-elements, 521 et seq. amount of radium emanation in, 524 et seq. ionization of, due to radium emana- tion, 526 Atom number of per c.c., 54 disintegration of, 234 et seq. complex nature of, 235 changing atoms, 444 et seq. possible causes of disintegration of, 486 evolution of, 496 Atomic weight of radium by chemical methods, 17 from spectroscopic evidence, 18 emanations, 273 of radio-elements and connection with radio-activity, 445 /3 rays discovery of, 113 magnetic deflection of, 114 complexity of, 116 examination by the electrical method, 118 effect of, on a fluorescent screen, 119 charge carried by the, 120 et seq. electrostatic deviation of, 124 velocity of, and value of elm for, 126 variation of e/m with velocity of, 127 et seq. distribution of velocity amongst /3 particles, 131 absorption of, 134 et seq. variation of absorption with density, 136 et seq. number of j3 particles stopped by matter, 137 et seq. variation of intensity of, with thick- ness of layer, 140 secondary ft rays, 189 et seq. relative ionization produced by a and /3 rays, 196 relative energy emitted in form of a and /3 rays, 196 et seq. phosphorescent action of, 201 et seq. physical action produced by, 207 et seq. chemical action of, 213 physiological action of, 216 from Ur X, 347 INDEX 561 ft rays (cont.) from active deposit of radium, 377 et seq. significance of appearance of, only in last radio-active changes, 455 change of weight due to expulsion of, 473 Barium platinocyanide phosphorescence of, under radium rays, 203 change of colour due to radium rays, 205 Barkla polarization of X rays, 80 Barnes and Eutherford heating effect of radium emanation, 421, 429 connection of heating effect with radio-activity, 421 heating effect of active deposit, 425 heating effect of 7 rays, 429 heating effect of emanation, 431 division of heating effect among active products, 433 Bary phosphorescence under radium rays, 202 Baskerville activity of thorium, 29 phosphorescence of kunzite under radium rays, 203 Baskerville and Kunz phosphorescence of substances under radium rays, 204 Beattie, Smolan and Kelvin discharging power of uranium rays, 7 Becquerel rays from calcium sulphide, 4 rays from uranium, 5 et seq. permanence of uranium rays, 6 discharging power of uranium rays, 6 magnetic deflection of radium rays by photographic method, 114 et seq. curvature of radium rays in a mag- netic field, 115 et seq. complexity of radium rays, 116 et seq. electrostatic deflection of /3 rays of radium, 124 et seq. value of ejm for /3 rays of radium, 126 et seq. magnetic deviation of a rays of radium and polonium, 145 trajectory of rays of radium in mag- netic field, 148 scintillations due to cleavage of crys- tals, 160 7 rays from radium, 179 secondary rays produced by active substances, 187 R. R.-A. Becquerel (cont.) phosphorescence produced by radium rays, 201 conductivity of paraffin under radium radiation, 210 effect of temperature on uranium rays, 210 chemical action of radium rays, 214 removal of activity from uranium by precipitation with barium, 219 theory of radio-activity, 438 Bemont et M. et Mme Curie discovery of radium, 13 Berndt spectrum of polonium, 23 Blanc thorium in sediments from hot springs, 514 Blythswood, Lord and Allen, H. S. radium emanation in Bath springs, 513 Bodlander and Eunge evolution of gases from radium, 215 Boltwood origin of radium, 460 amount of radium in minerals, 460 proportionality of uranium and ra- dium in minerals, 461 production of lead by uranium, 484 radium emanation in spring water, 514 method of standardization of amount of emanation in waters, 514 Boys rate of dissipation of charge, 531 Bragg and Kleeman theory of absorption of a rays, 172 et seq. relation between ionization and ab- sorption, 174 et seq. range of a rays in air, 174 four sets of a rays from radium, 174 et seq. Bronson use of steady deflection method with an electrometer, 104 decay of thorium emanation, 242 decay of excited activity from acti- nium, 312 Brooks, Miss variation of excited activity from thorium for short exposures, 304 effect of dust on distribution of excited activity, 305 decay curves of excited activity of radium measured by a and (3 rays, 307 et seq. decay curves of excited activity from actinium, 312 Brooks and Eutherford absorption of a rays by matter, 161 36 562 INDEX Brooks and Eutherford (cont.) comparison of absorption of a rays from radio-elements, 164 diffusion of radium emanation, 270 decay of excited activity from radium, 306 Bumstead presence of thorium emanation in atmosphere, 512 Bumstead and Wheeler diffusion of radium emanation, 273 emanation from surface water and the soil, 512, 522 identity of emanation from soil with radium emanation, 512, 522 Burton radium emanation in petroleum, 516 Burton and McLennan penetrating radiation from the earth, 520 radio-activity of ordinary materials, 537 emanation from ordinary matter, 538 Campbell radio-activity of ordinary materials, 540 Canal rays discovery of, 78 magnetic and electric deflection of, 78 value of e/m for, 78 similarity of, to a rays, 110 Capacity of electroscopes, 87 of electrometers, 94, 102 standards of, 102 Carbonic acid radio-activity of natural, 516 Caspari and Aschkinass action of radium rays on microbes, 216 Cathode rays discovery of, 73 magnetic and electric deflection of, 74 value of efm for, 75 radiation of energy from, 79 comparison of, with ft rays, 120 absorption of, by matter, 136, 137 see also ft rays Caves radio-active matter present in air of, 514 et seq. radio-activity of air of, due to emana- tion from the soil, 515 Changes (see Transformations) Charge carried by the ions, 50 et seq. negative charge carried by ft rays, 120 Charge (cont.) measurement of charge carried by ft rays, 121 et seq. positive charge carried by a rays, 145 measurement of charge carried by a rays, .151 et seq. Chemical nature of emanation, 267 of active deposit, 312 Chemical actions of radium rays production of ozone, 213 coloration of glass and rock-salt, 213 on phosphorus, 214 on iodoform, 214 on globulin, 214 evolution of hydrogen and oxygen. 215 Child potential gradient between electrodes, 65 variation of current with voltage for surface ionization, 66 Clouds formation of, by condensation of water round ions, 46 et seq. difference between positive and nega- tive ions in formation of, 49 Collie and Ramsay spectrum of emanation, 292 Collision ionization by, 39, 57 number of ions produced by ft rays per cm. of path, 434 total number of ions produced by collisions of a particles, 434 Coloration of crystals of radiferous barium, 15 of bunsen flame by radium, 15 of glass by radium rays, 213 of rock-salt, fluor-spar and potassium sulphate by radium rays, 213 Concentration of excited activity on negative elec- trode, 297 activity of radium independent of, 466 Condensation of water round the ions, 46 et seq. of emanations, 277 experimental illustration of, 279 temperature of, 280 difference between point of, for eman- ations of thorium and radium, 283 from air sucked up from the earth, 510 Conductivity of gases exposed to radiations, 31 et seq. variation of, with pressure, 61 et seq. variation of, with nature of gas, 64 comparison of, for gases exposed to a, ft, and 7 rays, 64 INDEX 563 Conductivity (cont.) comparison of, when exposed to y rays and to hard X rays, 184 of insulators, 209 of air in caves and cellars, 507 et seq. of air in closed vessels, 531 et seq. variation of, in closed vessels with pressure and nature of gas, 534 variation of, with temperature for air in closed vessels, 536 increase of, with time, in a closed vessel, 537 Conservation of radio-activity examples of, 469 et seq. Cooke, H. L. penetrating rays from the earth, 520 number of ions per c.c. in closed vessels, 534 radio-activity from ordinary matter, 536 Cooke, W. T. and Ramsay radio-activity produced by radiations of radium, 472 Corpuscle (see Electron) Crookes, Sir W. spectrum of radium, 17 spectrum of polonium, 23 nature of cathode rays, 73 nature of a rays, 142 scintillations produced by radium, 158 spinthariscope, 158 number of scintillations independent of pressure and temperature, 159 phosphorescence of diamond, 204 separation of Ur X, 219 theory of radio-activity, 441 Crookes and Dewar absence of nitrogen spectrum in phos- phorescent light of radium at low pressures, 206 Crystallization effect of, on activity of uranium, 349 Curie, Mme permanence of uranium rays, 6 discovery of radio-activity of thorium, 10 radio-activity of uranium and thorium minerals, 11 relative activity of compounds of uranium, 12 coloration of radium crystals, 15 spectrum of radium, 16 discovery of polonium, 22 nature of a rays, 142 absorption of a rays from polonium, 163 secondary radiation tested by electric method, 188 Curie, Mme (cont.) slowly decaying excited activity from radium, 311 recovery of activity of radium, 375 bismuth made active by solution of barium, 417 Curie, P. magnetic deviation of radium rays by electric method, 114 conductivity of dielectrics under ra- dium rays, 209 radio-activity of radium unaffected by temperature, 210 decay of activity of radium emana- tion, 247 discovery of excited radio-activity from radium, 295 • heat emission of radium at low tem- perature and variation of heat emission with age of radium, 419 nature of the emanation, 439 Curie, M. et Mme discovery of radium, 13 charge carried by ft rays, 121 luminosity of radium compounds, 205 production of ozone by radium rays, 213 coloration of glass by radium rays, 213 theory of radio-activity, 439 possible absorption by radio-elements of unknown radiations, 442 Curie, J. et P. quartz piezo-electrique, 105 et seq. Curie, P. et Danne diffusion of radio-active emanation, 272 decay of excited activity from radium, 309 decay curves of radium and equation, 309 occlusion of radium emanation in solids, 310 changes in radium, 381 effect of temperature on active de- posit, 390 Curie, P. and Debierne evolution of gas from radium, 215 active gases evolved from radium, 251 phosphorescence produced by radium emanation, 252 distribution of luminosity, 252 rate of production of emanation in- dependent of pressure, 266 effect of pressure on amount of excited activity, 266, 317 Curie and Dewar production of helium by radium, 479 Curie, P. and Laborde heat emission of radium, 419 36—2 564 INDEX Curie, P. and Laborde (cont.) origin of heat from radium, 440 radium emanation in waters of hot springs, 514 Current through gases, 31 et seq. variation of, with distance between the plates, 59 et seq. variation of, with pressure of gas, 61 et seq. variation of, with nature of gas, 64 measurement of, by galvanometer, 84 measurement of, by electroscope, 85 et seq. measurement of, by electrometer, 90 et seq. measurement of, by quartz piezo- electrique, 105 Dadourian presence of thorium emanation in the earth, 512 Danne on deposit of radium not containing uranium, 465 Danne et Curie diffusion of radio-active emanation, 272 decay of excited activity from radium, 309 decay curves of radium and equation, 309 occlusion of radium emanation in solids, 310 changes in radium, 381 effect of temperature on active de- posit, 390 Danysz action of radium rays on skin, 216 Darwin, G. H. age of sun, 492 Debierne actinium, 21 emanation from actinium, 249 decay of excited activity from acti- nium, 311 effect of magnetic field on activity excited from actinium, 324 barium made active by actinium, 417 Debierne and Curie evolution of gas from radium, 215 active gases evolved from radium, 251 phosphorescence produced by radium emanation, 252 distribution of luminosity, 252 rate of production of emanation in- dependent of pressure, 266 effect of pressure on amount of excited activity, 266, 317 Decay of activity of Th X, 221 of activity of Ur X, 223 significance of law of, 229 effect of conditions on the rate of, 232 of activity of thorium emanation, 241 of activity of radium emanation, 247 of activity of actinium emanation, 249 of excited activity due to thorium for long exposure, 302 " of excited activity due to thorium for short exposure, 304 of excited activity due to radium, 306 et seq. excited activity of slow decay due to radium, 311 of excited activity from actinium, 311 of radium A, B and C, 377 et seq. of radium D, E and F, 397 et seq. of heating effect of emanation, 423 of excited activity from atmosphere, 502 of activity of rain and snow, 506 of emanation from the earth, 508 differences in, of excited activity from atmosphere, 521 et seq. Demarcay spectrum of radium, 16 Deposit, active connection of, with excited activity, 301 physical and chemical properties of, 312 electrolysis of, 313 effect of temperature on, 315 effect of pressure on distribution of, 317 transmission of, by positive carriers, 318 et seq. nomenclature of, 328 theory of changes in, 331 et seq. theory of activity due to, 337 et seq. theory of rayless change in, 341 et seq. of thorium, 302 et seq., 351 et seq. analysis of, 351 rayless change in, 352 effect of temperature on, 354 period of products of, 355 of actinium, 311 et seq. decay curves of, 311 analysis of, 367 rayless change in, 367 period of products of, 368 radiations from, 368 of radium, 376 et seq. connection of excited activity with, 306 general analysis of, 376 et seq. analysis of, of rapid change, 377 et seq. INDEX 565 Deposit, active (cont.) of radium (cont.) analysis of a ray curves, 377 a ray curves of, 378 )8 ray curves of, 379 analysis of /3 ray curves, 381 equations of activity curves, 389 effect of temperature on, 390 volatility of, 391 %" of slow transformation, 311, 397 variation of a ray activity of, 398 variation of /3 ray activity of, 399 separation of constituents of, 401 et seq. successive products in, 402 variation of activity of, for long periods, 407 presence in old radium, 408 effect of, on variation of activity of radium with time, 409 presence in pitchblende, 410 connection with radio-tellurium, 411 connection with polonium, 411, 412 connection with radio-lead, 413 connection of, with radio-active in- duction, 415 et seq. heat emission of, 425 et seq. use of, to determine number of /3 particles from radium, 435 use of, as source of a rays, 543 Des Coudres magnetic and electric deviation of a rays, 148 determination of e/m for a rays, 148 Dewar emission of heat from radium in liquid hydrogen, 420 Dewar and Crookes absence of nitrogen spectrum in phos- phorescent light of radium at low pressures, 206 Dewar and Curie production of helium by radium, 479 Dielectrics condition of, under radium rays, 209 Diffusion of ions, 51 et seq of radium emanation into gases, 270 of thorium emanation into gases, 275 of radium emanation into liquids, 276 Discharge action of rays on spark and electrode- less, 208 Disintegration account of theory of, 234, 325, 445 list of products of, 449 rate of, in radio-elements, 457 emission of energy in consequence of, 474 et seq. helium a product of, 476 et seq. Disintegration (cont.) possible causes of, 486 et seq. of matter in general, 496 et seq. Dissipation of charge in caves and cellars, 514 et seq. in closed vessels, 531 effect of pressure and nature of gas on, 534 et seq. effect of material of vessel on, 536 et seq. Dolezalek electrometer, construction of, 94 et seq. Dorn charge carried by /3 rays, 122 electrostatic deflection of /3 rays from radium, 124 discovery of radium emanation, 246 effect of moisture on emanating power of thorium, 255 electrolysis of radium solution, 313 loss of weight of radium, 474 radium emanation in springs, 513 Dreyer and Salomonsen coloration of quartz by radium rays, 213 Dunston analysis of thorianite, 486 Durack ionization by collision of electrons of great velocity, 171 Dust effect of, on recombination of ions, 42 effect of, on distribution of excited activity, 305 Earth amount of radium in, 493 et seq. age of, 496 excited activity deposited on, 504 activity concentrated on peaks of, 504 emanation from, 507 very penetrating radiation from, 520 Ebert condensation of emanation from the earth, 510 apparatus for determining number of ions per c.c. in air, 527 velocity of ions in air, 528 Ebert and Ewers emanation from the earth, 508 Electrolysis separation of radio-tellurium by, 25 of solutions of active deposit, 313 of radium solutions, 313 of thorium solutions, 314 Electrometer description of, 90 et seq. use of, in measurements, 90 construction of, 91 et seq. Dolezalek, 94 566 INDEX Electrometer (cont.) adjustment and screening of, 95 special key for, 97 application of, to measurements of radio-activity, 97 et seq. measurement of current by, 100 capacity of, 101 use with steady deflection, 103 use with quartz piezo-61ectrique, 105 Electron definition of, 56 production of, under different con- ditions, 76 et seq. identity of /3 rays with electrons, 120 et seq. variation of apparent mass of electron with velocity, 127 et seq. evidence that mass of electron is electro-magnetic, 129 et seq. diameter of, 131 Electroscope description of, used by Curie, 85 construction of, for accurate measure- ments, 86 use of, in measurements of minute currents, 86 of C. T. E. Wilson, 89 use of, in measuring conductivity of air in closed vessels, 531 et seq. use of, for determining radio-activity of ordinary matter, 537 Elster and Geitel radio-active lead, 27 effect of magnetic field on conductivity produced in air by ft rays, 113 scintillations produced by active sub- stances, 158 action of radium rays on spark, 208 photo-electric action of body, coloured by radium rays, 214 radio-active matter in earth, 494 discovery of excited activity in atmo- sphere, 501 emanations from the earth, 507 radio-activity of air in caves, 507 radio-activity of the soil, 515 radio-activity of fango, 516 variation of radio-activity in atmo- sphere with meteorological condi- tions, 517 effect of temperature and pressure on atmospheric radio-activity, 518 Emanation of thorium, discovery and properties of, 238 methods of measurement of, 240 decay of activity of, 241 effect of thickness of layer on amount of, 243 Emanation (cont.) increase of, with time to a maximum, 245 of radium, 246 decay of activity of, 247 of actinium, properties of, 249 of radium, phosphorescence produced by, 251 rate of emission of, 254 effect of conditions on rate of emis- sion of, 255 regeneration of emanating power, 256 continuous rate of production of, 257 source of thorium emanation, 261 source of radium and actinium ema- nation, 263 radiations from, 263 effect of pressure on production of, 265 chemical nature of, 267 experiments to illustrate gaseous nature of, 268 rate of diffusion of radium emanation, 269 rate of diffusion of thorium emana- tion, 275 diffusion of, into liquids, 276 condensation of, 277 temperature of condensation of, 280 volume of, from one gram of radium and thorium, 288 measurement of volume of, from radium, 289 diminution of volume of, 290 spectrum of emanation, 292 connection between emanation and excited activity, 298 effect of removal of, on activity of radium, 371 et seq. fraction of activity of radium due to, 374 effect of rate of escape of, on activity of radium, 374 heat emission of, 420, 431 variation of heat emission with time, 421 et seq. enormous emission of energy from emanation, 431 radio-activity of atmosphere due to emanations, 504 sucked up from the earth, 507 in caves, 507 et seq. rate of decay of activity of, from the earth, 508 condensation of, from the atmo- sphere, 510 in well water and springs, 510 et seq. from " fango," 516 effect of meteorological conditions on amount of, in atmosphere, 517 et seq. INDEX 567 Emanation (cont.) from metals, 538 Emanating power measurement of, 254 effect of conditions on, 255 regeneration of, 256 Emanium or "emanating substance" of Giesel (see Actinium) discovery of, 21 separation and properties of, 21 similarity of, to actinium, 21 emanation from, 249 excited activity produced by, 311 action of an electric field on, 323 Energy of a particle, 156 of 0 particle, 196 comparison of, for a and |8 particles, 196 emitted from radium in form of heat, 419 et seq. emission of, from the emanation, 431 emission of, from radio-active pro- ducts of radium, 433 total emission of, from 1 gram of radio-elements, 474 et seq. latent store of, in matter, 475 Eve conductivity of gases exposed to X rays, 64 conductivity of gases exposed to X rays and 7 rays, 183, 184 secondary rays produced by ft and 7 rays, 189 et seq. magnetic deflection of secondary rays from 7 rays, 193 variation of activity of radium with concentration, 467 amount of radium emanation in the atmosphere, 524 et seq. ionization due to emanation in atmo- sphere, 526 et seq. Evolution of matter evidence of, 497 Ewers and Ebert emanation from the earth, 508 Excited radio-activity discovery and properties of, 295 et seq. concentration of, on negative elec- trode, 297 connection of, with the emanations, 298 removal of, by acids, 300 decay of, due to thorium, 302 decay of, for short exposure to thorium, 304 effect of dust on distribution of, 305 decay curves for different times of exposure, 306 et seq. decay of, from radium, 306 Excited radio-activity (cont.) decay curves of, measured by a rays, 308 decay curves of, measured by j8 rays, 309 decay curves of, from actinium, 311 of radium, of very slow decay, 311 effect of solution on, 312 electrolysis of active solutions, 313 effect of temperature on, 315 variation with electric field, of amount of, 316 effect of pressure on distribution of, 317 transmission of, 318 from actinium and emanium, 323 heat emission due to, 425 et seq. from the atmosphere, 501 et seq. decay of, 502 due to emanation in atmosphere, 504 distribution of, on surface of the earth, 504 concentration of, on prominences of the earth, 504 of rain and snow, 506 produced by emanation from tap water, 510 effect of meteorological conditions on amount of, 517 et seq. amount of, at Niagara Falls, 520 rate of decay of, dependent on con- ditions, 522 et seq. Exner and Haschek spectrum of radium, 17 Eye action of radium rays on, 217 Fehrle distribution of excited activity on a plate in electric field, 318 Fluorescence produced in substances by radium rays, 18 produced in substances by radium and polonium rays, 201 et seq. Fog large amount of excited activity during, 518 Forch loss of weight of radium, 474 7 rays relative conductivity of gas exposed to 7 and hard X rays, 64, 184 discovery of, 179 absorption of, by matter, 179 et seq. connection between absorption of, and density, 182 discussion of nature of rays, 182 et seq. 568 INDEX 7 rays (cont.) secondary rays produced by 7 rays, 189 measurement of radio-activity by means of, 442, 467 conservation of radio-activity measured by, 471 Gases evolved by radium, 215 presence of helium in gases from radium, 216 Gates, Miss F. effect of temperature on excited ac- tivity, 315 discharge of quinine sulphate, 530 Geitel natural conductivity of air in closed vessels, 501, 531 Geitel and Elster radio-active lead, 27 effect of magnetic field on conductivity produced by radium rays, 113 scintillations produced by active sub- stances, 158 action of radium rays on spark, 208 photo-electric action of bodies coloured by radium rays, 214 radio-active matter in earth, 494 discovery of radio-active matter in atmosphere, 501 emanations from the earth, 507 radio-activity of air in caves, 507 radio-activity of the soil, 515 radio-activity of fango, 516 variation of radio-activity of air with meteorological conditions, 517 effect of temperature and pressure on radio-activity in atmosphere, 518 Giesel coloration of bunsen flame by radium, 15 separation of radium by crystalli- zation of bromide, 15 emanating substance, 21 radio-active lead, 27 magnetic deviation of /3 rays, 113 decrease with time of luminosity of radio-active screen, 205 spectrum of phosphorescent light of emanium due to didymium, 206, 207 coloration of bodies by radium rays, 213 evolution of gases from radium, 215 action of radium rays on the eye, 217 emanation from the emanating sub- stance, 250 luminosity produced by radium ema- nation, 251 Giesel (cont.) decay of excited activity of emanium, 312 activity of radium dependent on age, 371 bismuth made active by radio-active solution, 417 temperature of radium bromide above air, 420 Gimingham and Kossignol decay of thorium emanation, 242 Glass coloration produced in, by radium rays, 213 phosphorescence produced in , by ema- nation, 252 Glew simple form of spinthariscope, and scintillations, 159 Globulin action of radium rays on, 214 Godlewski effect of crystallization on activity of uranium, 349 diffusion of uranium X, 350 separation of actinium X, 365 source of actinium emanation, 365 recovery and decay curves of actinium, 366 ' penetrating power of /3 and 7 rays from actinium, 368 radiations from active products, 368 Goldstein canal rays, 78 coloration of bodies by radium rays, 213 Gonder, Hofmann, and Wolfl properties of radio-active lead, 27, 413 Grier and Kutherford magnetic deviation of /3 rays of thorium, 114 relative current due to a and ft rays, 195 nature of rays from Ur X, 347 Hardy coagulation of globulin by radium rays, 214 Hardy and Miss Willcock coloration of iodoform solutions by radium rays, 214 Hardy and Anderson action of radium rays on the eye, 217 Harms number of ions per c.c. emission of, from radium at low temperatures, 420 connection of heat emission with the radio-activity, 421 et seq. source of heat energy, 421 et seq. rate of emission of, after removal of the emanation, 422 et seq. rate of emission of, by emanation, 423, 431 variation with time of heat emission of radium, and of its emanation, 423 heating effect of the emanation, 423, 431 heating effect of active deposit, 425 proportion of heating effect due to radio-active products, 433 origin of, in radium, 442 et seq. total heat emission during life of radio-elements, 474 et seq. heating of earth by radio-active matter, 493 Heaviside apparent mass of moving charged body, 71, 127 Helium produced by radium and its ema- nation, 476 et. seq. amount of, from radium, 480 origin of, 480 Helmholtz and Richarz action of ions on steam jet, 47 Hemptinne action of rays on spark and electrode- less discharge, 208 Henning resistance of radium solutions, 208 effect of voltage on amount of ex- cited activity, 316 Henning and Kohlrausch conductivity of solutions of radium bromide, 208 Hertz electric deviation of cathode rays, 73 Heydweiler loss of weight of radium, 474 Himstedt action of radium rays on selenium, 208 radium emanation in springs of Baden, 513 Himstedt and Meyer production of helium by radium, 479 Himstedt and Nagel action of radium rays on the eye, 217 Hofmann, Gonder, and Wolfl properties of radio-active lead, 27, 413 Hofmann and Strauss radio-active lead, 27 Hofmann and Zerban connection of activity of thorium with uranium, 29 Huggins, Sir W. and Lady spectrum of phosphorescent light of radium bromide, 205 Hydrogen production of, by radium rays, 215 Induced radio-activity (see Excited radio-activity) Induction radio-active, 24 meaning and examples of, 415 et seq. Insulators conduction of, under radium rays, 209 lo do form coloration produced in, by radium rays, 214 lonization theory of, to explain conductivity of gases, 31 et seq. by collision, 39, 57 variation of, with pressure of gas, 61 et seq. variation of, with nature of gas, 64 comparison of, produced by rays, 111, 194 production of, in insulators, 209 total, produced by 1 gram of radium, 433 et seq. natural ionization of gases, 531 et seq. connection of, with phosphorescent and photographic actions, 549 Ions in explanation of conductivity of gases, 31 et seq. production of, by collision, 39, 57 rate of recombination of, 40 et seq. mobility of, 42 et seq. difference between mobility of positive and negative, 43 et seq. condensation of water around, 46 et seq. difference between positive and nega- tive, 49 charge carried by, 50 diffusion of, 51 et seq. charge on an ion same as on hydrogen atom, 54 number of, produced per c.c., 54 size and nature of, 55 et seq. definition of, 56 et seq. 36—5 570 INDEX Ions (cont.) velocity acquired by, between col- lisions, 58 energy required to produce, 58, 551 comparative number of, produced in gases, 65 disturbance of potential gradient by movement of, 65 production of, in insulators, 209 number of, produced by a particle, 438 number produced per c.c. in closed vessels, 533 et seq. Joly motion of radium in an electric field, 211 absorption of radium rays by atmo- sphere, 492 (see foot-note) Kaufmann velocity of cathode rays, 75 variation of ejm with velocity of electron, 127 et seq. Kelvin theory of radio-activity, 441 age of sun and earth, 492, 493 Kelvin, Smolan and Beattie discharging power of uranium rays, 7 Kleeman and Bragg theory of absorption of a rays, 172 et seq. relation between ionization and ab- sorption, 174 et seq. range of a rays in air, 174 four sets of a rays from radium, 174 et seq. Kohlrausch conductivity of water altered by radium rays, 208 Kohlrausch and Henning conductivity of solutions of radium bromide, 208 Kunz phosphorescence of willemite and kunzite, 203 Kunz and Baskerville phosphorescence of substance under radium rays, 204 Kunzite phosphorescence of, under radium rays, 203 Laborde and Curie heat emission of radium, 419 origin of heat from radium, 440 radium emanation in waters of hot springs, 514 Langevin coefficient of recombination of ions, 41 Langevin (cont.) velocity of ions, 45 et seq. energy required to produce an ion, 58 secondary radiation produced by X rays, 187 slow moving ions in air, 528 Larmor radiation theory, 77 radiation of energy from moving electron, 79 structure of the atom, 157 Lead, radio-active preparation of, 26 radiations from, 26 Le Bon rays from bodies exposed to sunlight, 5 discharging power of quinine sulphate, 9,530 Lenard ionization of gases by ultra-violet light, 9 action of ions on a steam jet, 47 penetrating power of cathode rays, 73 negative charge carried by Lenard rays, 120 absorption of cathode rays propor- tional to density, 136, 137 Lerch, von chemical properties of active deposit of thorium, 313 electrolysis of solution of active de- posit, 313 effect of temperature on excited ac- tivity, 315 temporary activity of active deposit from thorium, 415 Lockyer inorganic evolution, 499 Lodge, Sir Oliver electronic theory, 69 instability of atoms, 487 Lorentz structure of atoms, 157 Lowry and Armstrong radio-activity and phosphorescence, 444 Luminosity of radium compounds, 205 change of, in radium compounds with time, 205 spectrum of phosphorescent light from radium bromide, 206 of radium compounds unaffected by temperature, 210 Mache radium emanation in hot springs, 513 Mache and von Schweidler velocity of ions in air, 528 INDEX 571 Makower diffusion of radium emanation, 274 diffusion of thorium emanation, 276 Marckwald preparation of radio-tellurium, 25 rate of decaj7 of radio-tellurium, 411 Mass apparent mass of electron, 71, 127 variation of mass of electron with speed, 127 et seq. of a particle, 147 et seq. Materials radio-activity of ordinary, 528, 536 et seq. Matteucci rate of dissipation of charge in closed vessels, 531 McClelland absorption of y rays, 181 secondary rays from /3 and 7 rays from radium, 192 McClung coefficient of recombination of ions, 41 conductivity of gases exposed to X rays, 64 ionization by a rays from radium C, 550 McClung and Kutherford energy required to produce an ion, 58 variation of current with thickness of layer of uranium, 195 estimate of energy radiated from radio - elements, 418 radiation of energy from radium, 438 McLennan absorption of cathode rays, 65 radio-activity of snow, 506 excited radios-activity at Niagara Falls, 519 McLennan and Burton penetrating radiation from the earth, 520 radio-activity of ordinary materials, 537 emanation from ordinary matter, 538 Metabolon definition of, 446 table of metabolons, 449 radio-elements as metabolons, 457 Meteorological conditions effect of, on radio-activity of atmo- sphere, 517 Methods of measurement in radio-activity, 82 et seq. comparison of photographic and elec- trical, 83 et seq. description of electrical, 84 et seq. Meyer and Himstedt production of helium by radium, 479 Meyer and Schweidler magnetic deviation of /3 rays by elec- trical method, 113 absorption of /3 rays of radium by matter, 136 activity proportional to amount of uranium, 195 emanation from uranium, 348 effect of crystallization on activity of uranium, 349 rate of decay of radio-tellurium, 411 Minerals, radio-active constant ratio of radium to uranium, 459 et seq. list of minerals, 461 age of, 485 composition of, 554 et seq. Mobility of ions, 43 et seq. Moisture effect of, on velocity of ions, 43, 45 effect of, on emanating power, 255 Molecule number of, in 1 c.c. of hydrogen, 54 Molecular weight of radium emanation, 273 of thorium emanation, 275 Nagel and Himstedt action of radium rays on the eye, 217 Niewenglowski rays from sulphide of calcium, 4 Nomenclature of successive products, 328 et seq. Number of molecules per c.c. of hydrogen, 54 of ions produced in gas by active sub- stances, 55 of j3 particles expelled from 1 gram of radium, 124 of a particles emitted per gram of radium, 155 of ions produced per c.c. in closed vessels, 534 Occlusion of emanation in thorium and radium, 258 of radium emanation by solids, 310 Owens saturation current affected by dust, 42 penetrating power of rays independent of compound, 164 absorption of a rays varies directly as the pressure of gas, 169 effect of air currents on conductivity produced by thorium, 238 Oxygen change into ozone, by radium rays, 213 572 INDEX Oxygen (cont.) production of, from radium solutions, 215 Ozone production of, by radium rays, 213 Paraffin objection to, as an insulator, 96 conductivity of, under radium rays, 210 Paschen distribution of velocity amongst ft particles, 131 et seq. absence of magnetic deflection of 7 rays, 183 7 rays and electrons, 185 heating effect of 7 rays, 186, 429 Patterson number of ions per c.c. in closed vessel, 534 natural conductivity of air due to an easily absorbed radiation, 536 effect of temperature on natural con- ductivity of air, 536 Peck and Willows action of radium rays on spark, 208 Pegram electrolysis of thorium solutions, 314 temporary activity of substances sepa- rated from thorium, 415 Penetrating power comparison of, for a, 0 and 7 rays, variation in, of ft rays, 134 et seq. variation of, with density for 8 rays, 137 comparison of, for a rays from radio- elements, 164 variation of, with density for a rays, 169 variation of, with density for 7 rays, 182 Penetrating radiation from the earth and atmosphere, 520 Perrin charge carried by cathode rays, 73 theory of radio-activity, 437 Phosphorescence production of, by radium, 19 production of, by radium and polo- nium rays, 201 et seq. comparison of, produced by a and 8 rays, 202 of zinc sulphide, 202 of barium platino-cyanide, 203 of willemite and kunzite, 203 produced by radium emanation in sub- stances, 203, 252 diminution of, with time, 205 of radium compounds, 205 Phosphorescence (cont.) spectrum of phosphorescent light of radium bromide, 205 spectrum of phosphorescent light of "emanium," 206 production of by heat (thermo-lumin- escence), 207 use of, to illustrate condensation of emanations, 279 connection of with ionization, 547 et seq. Phosphorus action of radium rays on, 214 ionization produced by, 529 Photo-electric action produced by radium rays in certain substances, 214 Photographic method, advantages and disadvant- ages of, 83 relative photographic action of rays, 83 connection of photographic action with ionization, 546 Physical action of radium rays on sparks, 208 on electrodeless discharge, 208 on selenium, 208 on conductivity of insulators, 209 Physiological action of radium rays production of burns, 216 effect on bacteria, 216 effect on eye, 217 Piezo-electrique of quartz description of, 105 Pitchblendes comparison of radio-activity of, 11 radio -elements separated from, 13 et seq. radium continually produced from, 459 constitution of, 557 Polarization of uranium rays absence of, 7 Polonium methods of separation of, 22 rays from, 23 decay of activity of, 23 discussion of nature of, 24 similarity to radio-tellurium, 26 magnetic deviation of a rays from, 146, 150 slow moving electrons, 153 increase of absorption with thickness of matter traversed, 163 connection of, with radium F, 411 Potential required to produce saturation, 32 et seq. fall of potential needed to produce ions at each collision, 58 INDEX 573 Potential (cont.) gradient due to movement of ions, 65 Precht and Kunge spectrum of radium, 17 atomic weight of radium, 18 heating effect of radium, 420 Pressure effect of, on velocity of ions, 46 effect of, on current through gases, 61 et seq. production of emanation independent of, 265 effect of, on distribution of excited activity, 317 effect of, on natural conductivity of air in closed vessels, 534 Products, radio-active list of, from radio-elements, 449 properties of, 449 amount of in radium, 452 et seq. radiations from, 455 Quartz piezo-electrique use of, in measurement of current, 105 Quinine sulphate discharging power of, 530 phosphorescence of, 530 Radiations emitted by uranium, 8 emitted by thorium, 10 emitted by radium, 18 emitted by actinium, 21 emitted by polonium, 23 method of measurement of, 82 et seq. methods of comparison of, 108 three kinds of, 109 analogy to rays from a Crookes tube, 110 relative ionizing and penetrating power of, 111 difficulties of comparative measure- ment of, 112 /3 rays, 113 a rays, 141 7 rays, 179 secondary rays, 187 comparison of ionization of a and p rays, 194 phosphorescent effect of, 201 et seq. physical actions of, 207 et seq. chemical actions of, 213 et seq. physiological actions of, 216 from the emanation, 263 from Ur X, 347 connection of, with heat emission, 421 et seq. from different active products, 455 Eadiations (cont.) conservation of energy of each specific type of, 469 et seq. Radio-lead connection of, with polonium, 411 et seq. connection of, with radium D, 413 Radio-tellurium rate of decay of, 411 connection of with radium F, 411 Radium discovery of, 13 separation of, 13 spectrum of, 16 atomic weight of, 17 radiations from, 18 compounds of, 19 nature of radiations from, 109 |8 rays from, 113 a rays from, 141 7 rays from, 179 secondary rays from, 187 production of phosphorescence by, 201 et seq. spectrum of phosphorescent light of, 206 physical actions of, 207 et seq. chemical actions of, 213 et seq. physiological actions of, 216 emanation from, 246 properties of emanation from, 247 et seq. chemical nature of emanation from, 267 diffusion of emanation from, 269 condensation of emanation from, 277 amount of emanation from, 288 volume of emanation from, 289 spectrum of emanation from, 292 excited radio-activity from, 295 et seq. decay of excited activity from, 306 et seq. difference in properties of radium and the emanation, 327 nomenclature of products, 328 theory of successive changes in, 330 alteration of activity of, by removal of emanation, 371 et seq. recovery of activity of, after removal of emanation, 372 effect of escape of emanation on re- covery of activity of, 374 non-separable activity of, 375 period and properties of radium A, B and C, 376 et seq. analysis of active deposit of rapid changes of radium, 377 analysis of fi ray curves, 381 et seq. analysis of a ray curves, 386 et seq. equations of activity curves, 389 574 INDEX Eadium (cont.) effect of temperature on active de- posit of, 390 relative activity due to products of, 395 active deposit of slow transformation, 397 physical and chemical properties of radium D, E and F, 398 et seq. effect of temperature on active de- posit of slow change, 401 separation of radium F by bismuth, 402 products of, 402 et seq. rate of transformation of radium D, 404 et seq. variation of the activity of the active deposit over long periods of time, 407 amounts of radium D, E and F in old radium, 408 variation of activity of, with time, 409 products of in pitchblende, 410 origin of radio- tellurium, 411 origin of polonium, 411, 412 origin of radio-lead, 413 temporary activity of inactive matter separated from pitchblende, 415 et seq. heat emission of, 419 et seq. heat emission of emanation from, 420, 431 heating effects due to products of, 433 theories of radio-activity of, 437 et seq. discussion of theories of radio-activity of, 441 et seq. energy of radiations, not derived from external source, 442 et seq. theory of radio-active change, 444 et seq. list of active products of, 449 amount of products of, 452 rate of change of, 457 life of radium, 457 origin of, 459 et seq. production of, by uranium, 459 et seq. amount of in 1 gram of uranium, 461 amount of, in minerals, 461 radio-activity of, independent of con- centration, 466 et seq. disappearance of, 467 life of, independent of concentration, 468 conservation of radio-activity of, 469 et seq. loss of weight of, 473 experiments to determine loss of weight of, 474 Eadium (cont.) total emission of energy from 1 gram of, 474 et seq. 