Radio-Activity

by Ernest Rutherford

INDEX.

The numbers refer to the pages.

• α 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 α 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 α rays from radio-elements, [164]
  • absorption of, by gases, [165] et seq.
  • connection between absorption and density, [169]
  • relation between ionization and absorption, [170]
  • theory of absorption of, [170] et seq.
  • range of ionization of, [172] et seq.
  • complexity of α rays from radium, [174] et seq.
  • effect of thickness of layer of radiating matter on emission of, [195]
  • relative ionization produced by α and β rays, [196] et seq.
  • phosphorescence by α 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 α rays, [419] et seq.
  • connection of heat emission of radium with α rays, [421] et seq.
  • number of ions produced by an α particle, [433]
  • absence of, in rayless changes, [454]
  • emission from active products, [454] et seq.
  • loss of weight due to expulsion of, [473]
  • α 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, photographic, and ionization effects produced by, [546] et seq.
  • energy required to produce an ion by α rays, [551]
• Abraham
  • apparent mass of moving charged body, [71], [127]
• Absorption
  • law of, in gases, [64] et seq.
  • relative absorption of α, β and γ rays by matter, [111]
  • connection between absorption and ionization, [134] et seq., [170] et seq.
  • of β rays by solids, [134] et seq.
  • connection between absorption and density for β rays, [137]
  • of β rays in radio-active matter, [140]
  • of α rays by solids, [161] et seq.
  • of α rays in gases, [167], [170] et seq.
  • connection between absorption and density for α rays, [169]
  • theory of, [170] et seq.
  • of γ rays by solids, [179] et seq.
  • connection between absorption and density for γ 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]
  • 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 β and γ rays from, [368]
  • products of, [369]
  • table of products of, [448]
  • 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]
  • 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 emanation, [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]
• β 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 e/m for, [126]
  • variation of e/m with velocity of, [127] et seq.
  • distribution of velocity amongst β particles, [131]
  • absorption of, [134] et seq.
  • variation of absorption with density, [136] et seq.
  • number of β particles stopped by matter, [137] et seq.
  • variation of intensity of, with thickness of layer, [140]
  • secondary β rays, [189] et seq.
  • relative ionization produced by α and β rays, [196]
  • relative energy emitted in form of α and β 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]
  • 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 Rutherford
  • heating effect of radium emanation, [421], [429]
  • connection of heating effect with radio-activity, [421]
  • heating effect of active deposit, [425]
  • heating effect of γ 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 magnetic field, [115] et seq.
  • complexity of radium rays, [116] et seq.
  • electrostatic deflection of β rays of radium, [124] et seq.
  • value of e/m for β rays of radium, [126] et seq.
  • magnetic deviation of α rays of radium and polonium, [145]
  • trajectory of rays of radium in magnetic field, [148]
  • scintillations due to cleavage of crystals, [160]
  • γ rays from radium, [179]
  • secondary rays produced by active substances, [187]
  • 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]
• Bödlander and Runge
  • evolution of gases from radium, [215]
• Boltwood
  • origin of radium, [460]
  • amount of radium in minerals, [460]
  • proportionality of uranium and radium 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 α rays, [172] et seq.
  • relation between ionization and absorption, [174] et seq.
  • range of α rays in air, [174]
  • four sets of α 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 actinium, [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 α and β rays, [307] et seq.
  • decay curves of excited activity from actinium, [312]
• Brooks and Rutherford
  • absorption of α rays by matter, [161]
  • comparison of absorption of α 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 α 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 e/m for, [75]
  • radiation of energy from, [79]
  • comparison of, with β rays, [120]
  • absorption of, by matter, [136], [137]
  • see also [β rays]
• Caves
  • radio-active matter present in air of, [514] et seq.
  • radio-activity of air of, due to emanation from the soil, [515]
• Changes
  • (see [Transformations])
• Charge
  • carried by the ions, [50] et seq.
  • negative charge carried by β rays, [120]
  • measurement of charge carried by β rays, [121] et seq.
  • positive charge carried by α rays, [145]
  • measurement of charge carried by α 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 negative ions in formation of, [49]
• Collie and Ramsay
  • spectrum of emanation, [292]
• Collision
  • ionization by, [39], [57]
  • number of ions produced by β rays per cm. of path, [434]
  • total number of ions produced by collisions of α 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 electrode, [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 emanations 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 α, β, and γ rays, [64]
  • comparison of, when exposed to γ 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 α 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 phosphorescent 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 α rays from polonium, [163]
  • secondary radiation tested by electric method, [188]
  • 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 radium rays, [209]
  • radio-activity of radium unaffected by temperature, [210]
  • decay of activity of radium emanation, [247]
  • discovery of excited radio-activity from radium, [295]
  • heat emission of radium at low temperature 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 β 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-électrique, [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 deposit, [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 independent 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]
  • 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-électrique, [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 deposit, [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 actinium, [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 independent 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.
• Demarçay
  • 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.
    • analysis of α ray curves, [377]
    • α ray curves of, [378]
    • β ray curves of, [379]
    • analysis of β ray curves, [381]
    • equations of activity curves, [389]
    • effect of temperature on, [390]
    • volatility of, [391]
    • of slow transformation, [311], [397]
    • variation of α ray activity of, [398]
    • variation of β 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 induction, [415] et seq.
    • heat emission of, [425] et seq.
    • use of, to determine number of β particles from radium, [435]
    • use of, as source of α rays, [543]
• Des Coudres
  • magnetic and electric deviation of α rays, [148]
  • determination of e/m for α rays, [148]
• Dewar
  • emission of heat from radium in liquid hydrogen, [420]
• Dewar and Crookes
  • absence of nitrogen spectrum in phosphorescent 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 electrodeless, [208]
• Disintegration
  • account of theory of, [234], [325], [445]
  • list of products of, [448]
  • rate of, in radio-elements, [457]
  • emission of energy in consequence of, [474] et seq.
  • helium a product of, [476] et seq.
  • 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 β rays, [122]
  • electrostatic deflection of β 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]
  • 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-électrique, [105]
• Electron
  • definition of, [56]
  • production of, under different conditions, [76] et seq.
  • identity of β rays with electrons, [120] et seq.
  • variation of apparent mass of electron with velocity, [127] et seq.
  • evidence that mass of electron is electromagnetic, [129] et seq.
  • diameter of, [131]
• Electroscope
  • description of, used by Curie, [85]
  • construction of, for accurate measurements, [86]
  • use of, in measurements of minute currents, [86]
  • of C. T. R. 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 β rays, [113]
  • scintillations produced by active substances, [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 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 in atmosphere with meteorological conditions, [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]
  • 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 emission of, [255]
  • regeneration of emanating power, [256]
  • continuous rate of production of, [257]
  • source of thorium emanation, [261]
  • source of radium and actinium emanation, [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 emanation, [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 atmosphere, [510]
  • in well water and springs, [510] et seq.
  • from “fango,” [516]
  • effect of meteorological conditions on amount of, in atmosphere, [517] et seq.
  • 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 α particle, [156]
  • of β particle, [196]
  • comparison of, for α and β particles, [196]
  • emitted from radium in form of heat, [419] et seq.
  • emission of, from the emanation, [431]
  • emission of, from radio-active products 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 γ rays, [183], [184]
  • secondary rays produced by β and γ rays, [189] et seq.
  • magnetic deflection of secondary rays from γ 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 atmosphere, [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 electrode, [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]
  • decay curves of, measured by α rays, [308]
  • decay curves of, measured by β 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 conditions, [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]
• γ rays
  • relative conductivity of gas exposed to γ 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.
  • secondary rays produced by γ 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 activity, [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 substances, [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 crystallization of bromide, [15]
  • emanating substance, [21]
  • radio-active lead, [27]
  • magnetic deviation of β 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 substance, [250]
  • luminosity produced by radium emanation, [251]
  • 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 Rossignol
  • decay of thorium emanation, [242]
• Glass
  • coloration produced in, by radium rays, [213]
  • phosphorescence produced in, by emanation, [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 β and γ rays from actinium, [368]
  • radiations from active products, [368]
• Goldstein
  • canal rays, [78]
  • coloration of bodies by radium rays, [213]
• Gonder, Hofmann, and Wölfl
  • properties of radio-active lead, [27], [413]
• Grier and Rutherford
  • magnetic deviation of β rays of thorium, [114]
  • relative current due to α and β 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. in closed vessel, [534]
• Hartmann
  • spectrum of phosphorescent light of emanium, [206]
• Haschek and Exner
  • spectrum of radium, [17]
• Heat
  • rate of emission of, from radium, [419] et seq.
  • 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 emanation, [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 electrodeless discharge, [208]
• Henning
  • resistance of radium solutions, [208]
  • effect of voltage on amount of excited 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 Wölfl
  • 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]
• Iodoform
  • coloration produced in, by radium rays, [214]
• Ionization
  • 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 negative, [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.
  • velocity acquired by, between collisions, [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 α particle, [433]
  • 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 atmosphere, [492] (see footnote)
• Kaufmann
  • velocity of cathode rays, [75]
  • variation of e/m 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 α rays, [172] et seq.
  • relation between ionization and absorption, [174] et seq.
  • range of α rays in air, [174]
  • four sets of α 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]
  • 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 proportional to density, [136], [137]
• Lerch, von
  • chemical properties of active deposit of thorium, [313]
  • electrolysis of solution of active deposit, [313]
  • effect of temperature on excited activity, [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]
• Makower
  • diffusion of radium emanation, [274]
  • diffusion of thorium emanation, [276]
• Marckwald
  • preparation of radio-tellurium, [25]
  • rate of decay of radio-tellurium, [411]
• Mass
  • apparent mass of electron, [71], [127]
  • variation of mass of electron with speed, [127] et seq.
  • of α 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 γ rays, [181]
  • secondary rays from β and γ rays from radium, [192]
• McClung
  • coefficient of recombination of ions, [41]
  • conductivity of gases exposed to X rays, [64]
  • ionization by α rays from radium C, [550]
• McClung and Rutherford
  • 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 radio-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, [448]
  • radio-elements as metabolons, [457]
• Meteorological conditions
  • effect of, on radio-activity of atmosphere, [517]
• Methods of measurement
  • in radio-activity, [82] et seq.
  • comparison of photographic and electrical, [83] et seq.
  • description of electrical, [84] et seq.
• Meyer and Himstedt
  • production of helium by radium, [479]
• Meyer and Schweidler
  • magnetic deviation of β rays by electrical method, [113]
  • absorption of β 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 substances, [55]
  • of β particles expelled from 1 gram of radium, [124]
  • of α 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 α 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]
  • 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 β particles, [131] et seq.
  • absence of magnetic deflection of γ rays, [183]
  • γ rays and electrons, [185]
  • heating effect of γ 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 conductivity of air, [536]
• Peck and Willows
  • action of radium rays on spark, [208]
• Pegram
  • electrolysis of thorium solutions, [314]
  • temporary activity of substances separated from thorium, [415]
• Penetrating power
  • comparison of, for α, β and γ rays, [111]
  • variation in, of β rays, [134] et seq.
  • variation of, with density for β rays, [137]
  • comparison of, for α rays from radio-elements, [164]
  • variation of, with density for α rays, [169]
  • variation of, with density for γ 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 polonium rays, [201] et seq.
  • comparison of, produced by α and β rays, [202]
  • of zinc sulphide, [202]
  • of barium platinocyanide, [203]
  • of willemite and kunzite, [203]
  • produced by radium emanation in substances, [203], [252]
  • diminution of, with time, [205]
  • of radium compounds, [205]
  • spectrum of phosphorescent light of radium bromide, [205]
  • spectrum of phosphorescent light of “emanium,” [206]
  • production of by heat (thermo-luminescence), [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 disadvantages 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-électrique 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 α 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]
  • gradient due to movement of ions, [65]
• Precht and Runge
  • 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, [448]
  • properties of, [448]
  • amount of in radium, [452] et seq.
  • radiations from, [455]
• Quartz piezo-électrique
  • 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 measurement of, [112]
  • β rays, [113]
  • α rays, [141]
  • γ rays, [179]
  • secondary rays, [187]
  • comparison of ionization of α and β 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]
  • 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]
  • β rays from, [113]
  • α rays from, [141]
  • γ 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 recovery 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 β ray curves, [381] et seq.
  • analysis of α ray curves, [386] et seq.
  • equations of activity curves, [389]
  • effect of temperature on active deposit 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 deposit 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, [448]
  • 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 concentration, [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]
  • total emission of energy from 1 gram of, [474] et seq.
  • production of helium from, [476]
  • helium, disintegration product of, [479] et seq.
  • amount of helium from, [480]
  • possible causes of disintegration of, [486] et seq.
  • amount of, to account for heat of sun, [491]
  • possible connection of with heat of sun, [491]
  • possible connection of with heat of earth, [493]
  • probable amount of, in earth, [495]
  • amount of, in atmosphere, [495], [524]
  • presence of, in atmosphere, [521] et seq.
• Radium A
  • decay curve of, [378]
  • radiation from, [381]
  • effect of, on activity curves, [386] et seq.
  • connection with later changes, [392]
  • activity supplied by, [393]
• Radium B
  • absence of rays in, [381]
  • effect of, on activity curves, [381] et seq.
  • effect of temperature on, [390]
  • volatility of, [390]
  • absence of heating effect of, [433]
  • nature of rayless change in, [454], [552]
• Radium C
  • radiations from, [381]
  • analysis of β ray curves of, [381] et seq.
  • analysis of α ray curves of, [386] et seq.
  • effect of temperature on, [390]
  • activity supplied by, [394] et seq.
  • heating effect of, [425]
  • use of, as a source of β rays, [435]
  • explosive nature of change in, [456]
  • magnetic deflection of rays from, [543]
  • velocity and value of e/m for rays from, [544]
• Radium D
  • origin of name of, [376]
  • connection of, with active deposit, [403]
  • period of transformation of, [406]
  • effect of, on variation of activity, [407]
  • presence in old radium, [408]
  • effect of, on activity of old radium, [409]
  • presence in pitchblende, [410]
  • connection with radio-lead, [413]
  • amount of, in 1 ton of uranium, [454]
• Radium E
  • effect of temperature on, [401]
  • connection of, with β ray activity active deposit, [403], [400]
  • connection with radio-lead, [413]
• Radium F
  • variation of activity due to, [398]
  • effect of temperature on, [401]
  • separation of, on bismuth plate, [402]
  • connection with active deposit, [403]
  • variation of activity of, over long periods of time, [407]
  • presence in old radium, [409]
  • effect of, on activity of old radium, [409]
  • presence in pitchblende, [410]
  • connection with radio-tellurium, [411]
  • connection with polonium, [411], [412]
  • connection with radio-lead, [413]
• Rain
  • radio-activity of, [505]
  • decay of activity of, [506]
• Ramsay, Sir W.
  • amount of helium in thorianite, [486]
• Ramsay and Collie
  • spectrum of emanation, [292]
• Ramsay and Cooke
  • radio-activity produced by radiation from radium, [472]
• Ramsay and Soddy
  • evolution of gas from radium, [215]
  • production of hydrogen and oxygen from radium, [215]
  • chemical nature of the emanation, [268]
  • gaseous nature of the emanation, [268]
  • volume of emanation, and change with time, [289]
  • helium from radium emanation, [291]
  • amount of helium produced by radium, [480]
• Ramsay and Travers
  • amount of helium in fergusonite, [486]
• Rayless changes
  • discussion of, [454], [552]
• Re, F.
  • theory of radio-activity, [441]
• Recombination
  • of ions, [40] et seq.
  • constant of, [42]
• Recovery
  • of activity of thorium after removal of Th X, [221]
  • of activity of uranium after removal of Ur X, [223]
  • significance of law of, [224]
  • effect of conditions on rate of, [232]
  • of activity of radium after removal of emanation, [372]
  • of heating effect of radium, [423]
• Reflection
  • no evidence of direct reflection for uranium rays, [7]
  • diffuse reflection of rays, [7]
• Refraction
  • no evidence of, for uranium rays, [7]
• Regeneration
  • of emanating power, [256]
• Richarz and von Helmholtz
  • action of ions on steam jet, [47]
• Richarz and Schenck
  • theory of radio-activity, [441]
• Rossignol and Gimingham
  • decay of thorium emanation, [242]
• Runge
  • spectrum of radium, [17]
• Runge and Bödlander
  • evolution of gas from radium, [215]
• Runge and Precht
  • spectrum of radium, [17]
  • atomic weight of radium, [18]
  • heating effect of radium, [420]
• Russel
  • photographic action of substances, [83]
• Saake
  • amount of emanation in air at high altitudes, [519]
• Salomonsen and Dreyer
  • coloration of quartz by radium rays, [213]
• Saturation current
  • meaning of, [33] et seq.
  • application of, to measurements of radio-activity, [84]
  • measurement of, [100] et seq.
• Schenck
  • radium emanation in springs, [513]
• Schenck and Richarz
  • theory of radio-activity, [441]
• Schmidt
  • discovery of radio-activity of thorium, [10]
• Schmidt and Wiedemann
  • thermo-luminescence, [207]
• Schuster
  • number of ions per c.c. in air of Manchester, [528]
  • radio-activity of matter, [529]
• Schweidler and Mache
  • velocity of ions in air, [528]
• Schweidler and Meyer
  • magnetic deviation of β rays by electrical method, [113]
  • absorption of β 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]
• Scintillations
  • discovery of, in zinc sulphide screen, [158]
  • connection of, with α rays, [158]
  • illustration of, by spinthariscope, [158]
  • cause of, [160]
  • production of, by action of electric field, [160]
• Searle
  • apparent mass of moving charged body, [71], [127]
• Secondary rays
  • examination of, by photographic method, [187]
  • examination of, by electrical method, [188]
  • production of, by β and γ rays, [189] et seq.
  • from different materials, [191]
  • amount of, depends upon atomic weight, [192]
  • magnetic deflection of, [193]
• Seitz
  • absorption of electrons by matter, [137] et seq.
• Selenium
  • action of radium rays on, [208]
• Simon
  • value of e/m for cathode rays, [75], [129]
• Simpson
  • amount of excited activity in north of Norway, [519]
• Slater, Miss
  • effect of temperature on active deposit of thorium, [354]
• Smolan, Beattie and Kelvin
  • discharging power of uranium rays, [7]
• Snow
  • radio-activity of, [506]
  • decay of activity of, [507]
• Soddy
  • comparison of photographic and electrical action of uranium rays, [83]
  • nature of rays from Ur X, [347]
  • production of radium from uranium, [463]
• Soddy and Ramsay
  • evolution of gas from radium, [215]
  • production of hydrogen and oxygen from radium, [215]
  • chemical nature of the emanation, [268]
  • gaseous nature of the emanation, [268]
  • volume of the emanation, and change with time, [289]
  • helium from radium emanation, [291]
  • amount of helium produced by radium, [480]
• Soddy and Rutherford
  • separation of Th X, [220]
  • decay of activity of Th X, [221]
  • recovery of activity of thorium freed from Th X, [221]
  • decay of activity of Ur X, [223]
  • recovery of activity of uranium freed from Ur X, [223]
  • explanation of decay and recovery curves, [224]
  • rate of production of Th X, [227]
  • theory of decay of activity, [229]
  • influence of conditions on rate of decay and recovery of activity, [233]
  • disintegration hypothesis, [234]
  • decay of activity of radium emanation, [247]
  • measurements of emanating power, [254]
  • effect of temperature, moisture, and solution, on emanating power, [255]
  • regeneration of emanating power, [256]
  • constant rate of production of emanation of radium and thorium, [257]
  • source of thorium emanation, [261]
  • radiations from the emanation, [264]
  • chemical nature of emanation, [267]
  • condensation of emanations of radium and thorium, [277]
  • temperature of condensation of emanation, [278]
  • effect of successive precipitations on activity of thorium, [358]
  • recovery of activity of radium, [372]
  • theory of radio-activity, [439]
  • theory of radio-active change, [445]
  • conservation of radio-activity, [469]
• Soil
  • radio-activity of, [507] et seq.
  • difference in activity of, [508] et seq.
• Solution
  • coloration of, by radium, [15]
  • of active deposit in acids, [312]
  • electrolysis of active, [313]
• Source
  • of thorium emanation, [261]
  • of radium and actinium emanations, [263]
• Spark
  • action of radium rays on, [208]
• Spectrum
  • spark spectrum of radium, [15], [16]
  • flame spectrum of radium, [17]
  • effect of a magnetic field on spectrum of radium, [17]
  • of polonium, [23]
  • of phosphorescent light of radium bromide, [206]
  • of emanation, [292]
  • of helium in radium gases and emanation, [477]
• Spinthariscope
  • description of, [158]
• Springs
  • emanation from water of, [513]
• Stark
  • energy to produce an ion, [58]
• Stoney, Johnstone
  • use of term electron, [76]
• Strauss and Hofmann
  • radio-active lead, [27]
• Strutt
  • conductivity of gases for radiation, [63], [64]
  • conductivity of gases produced by γ rays, [64], [183]
  • negative charge carried by β rays, [122] et seq.
  • absorption of β rays proportional to density, [136]
  • nature of α rays, [142]
  • attempt to measure charge of α rays, [153]
  • constant ratio of uranium to radium in minerals, [462]
  • connection of thorium with helium, [483]
  • absorption of radium rays from sun by atmosphere, [492]
  • presence of radium in Bath waters, [513]
  • radio-activity of ordinary matter, [536]
• Sun
  • effect of radium in, [491]
  • age of, [492]
• Temperature
  • effect of, on intensity of radiations from uranium and radium, [210]
  • effect of, on luminosity, [210]
  • rate of decay of radium emanation unaffected by, [249]
  • of condensation of emanations, [283]
  • rate of decay of thorium emanation unaffected by, [287]
  • effect of, on excited activity, [315]
  • effect of, on active deposit of thorium, [354]
  • effect of, on active deposit of actinium, [368]
  • effect of, on active deposit of rapid change of radium, [390]
  • effect of, on active deposit of slow change, [401]
  • of radium above surrounding space, [419]
  • effect of, on amount of excited activity in atmosphere, [518]
  • effect of, on natural ionization of air, [536]
• Theories
  • of radio-activity, review of, [437] et seq.
  • discussion of, [441] et seq.
  • disintegration theory, [445] et seq.
• Thermo-luminescence, [207]
• Thomson, J. J.
  • relation between current and voltage for ionized gases, [34]
  • difference between ions as condensation nuclei, [49]
  • charge on ion, [50]
  • magnetic field produced by an ion in motion, [69]
  • apparent mass of electron, [71]
  • action of magnetic field on moving ion, [72]
  • determination of e/m for cathode stream, [73]
  • origin of X rays, [80]
  • slow velocity electrons from radio-tellurium, [153]
  • charge carried by α rays, [154]
  • theory of radio-activity, [440]
  • cause of heat emission from radium, [442]
  • structure of atom, [487]
  • possible causes of disintegration of radium, [487]
  • nature of electrons, [496]
  • emanation from tap-water and deep wells, [510]
  • radio-activity of ordinary materials, [539]
• Thomson, J. J. and Rutherford
  • ionization theory of gases, [31] et seq.
• Thorium
  • discovery of radio-activity of, [10]
  • emanation from, [11]
  • preparation of non-radio-active thorium, [29]
  • nature of radiations from, [109]
  • β rays from, [114]
  • α rays from, [141]
  • γ rays from, [180]
  • separation of Th X from, [220]
  • recovery of activity of, [221]
  • disintegration of, [234]
  • emanation from, [238]
  • properties of emanation from, [239]
  • diffusion of emanation from, [275]
  • condensation of emanation from, [277]
  • excited radio-activity from, [295] et seq.
  • analysis of active deposit of, [351] et seq.
  • rayless change in, [352]
  • explanation of initial portion of decay curve, [358]
  • explanation of initial portion of recovery curve, [358]
  • effect of successive precipitations on, [358]
  • recovery curve after large number of precipitations, [359]
  • products of, [363]
  • non-separable activity of, [363]
  • radiations from active products of, [363]
  • division of activity amongst active products of, [363]
  • rate of emission of energy by, [432]
  • theories of radio-activity of, [438]
  • discussion of theories of radio-activity, [441] et seq.
  • source of energy of radiations, [442] et seq.
  • theory of radio-active change, [444] et seq.
  • table of radio-active products of, [448]
  • rate of change of, [458]
  • life of, [458]
  • conservation of radio-activity of, [469]
  • total emission of energy from 1 gram of, [475]
  • possible causes of disintegration of, [486] et seq.
• Thorium A
  • period and properties of, [352] et seq.
  • absence of rays in, [352]
  • effect of temperature on, [354]
• Thorium B
  • period and properties of, [352] et seq.
  • effect of temperature on, [354]
  • radiations from, [363]
• Thorium X
  • methods of separation of, [220]
  • law of decay of activity of, [221]
  • law of recovery of activity of, [221]
  • theory to explain production of, [224]
  • material nature of, [226]
  • continuous production of, [227]
  • explanation of decay of activity of, [229]
  • effect of conditions on the rate of change of, [233]
  • disintegration hypothesis to explain production of, [234]
  • minute amount of, produced, [237]
  • effect of successive separations of, on activity of thorium, [358] et seq.
  • analysis of decay and recovery curves of, [358]
  • radiations from, [363]
• Tommasina
  • scintillations produced by electrification, [160]
• Townsend
  • ions by collision, [39], [57]
  • coefficient of recombination, [41]
  • diffusion of ions, [51] et seq.
  • comparison of charge on ion with that on hydrogen atom in electrolysis, [53]
  • number of molecules per c.c. of gas, [54]
  • ionization by collision for different speeds, [171]
• Transformations, successive
  • theory of, [325] et seq.
  • nomenclature of, [328]
  • activity due to, [337]
  • detection of a rayless change in, [341]
  • in uranium, [346] et seq.
  • in thorium, [351] et seq.
  • in actinium, [364] et seq.
  • in radium, [371] et seq.
  • list of, [448]
  • origin of radium in, [459]
  • helium, a result of, [476] et seq.
  • possible cause of, [486] et seq.
  • application of, to evolution of matter, [497] et seq.
• Transmission
  • of excited radio-activity of radium and thorium, [318] et seq.
  • of excited radio-activity of actinium, [323]
• Travers and Ramsay
  • amount of helium in fergusonite, [486]
• Troost
  • rays from hexagonal blende, [4]
• Uranium
  • discovery of radio-activity of, [5]
  • persistence of radiations of, [6]
  • discharging power of rays, [7]
  • absence of reflection, refraction and polarization, [7]
  • examination of uranium minerals, [11] et seq.
  • relative activity of compounds of uranium, [12]
  • nature of radiations from, [109]
  • β rays from, [114]
  • α rays from, [141]
  • γ rays from, [180]
  • separation of Ur X from, [219]
  • recovery of activity of, [219]
  • changes in, [346] et seq.
  • non-separable activity of, [347]
  • radiations from Ur X, [347] et seq.
  • method of measurement of activity of Ur X, [347]
  • emission of energy by, [418]
  • theories of radio-activity of, [437] et seq.
  • discussion of theories of radio-activity, [441] et seq.
  • source of energy of radiation, [442] et seq.
  • theory of radio-active change, [444] et seq.
  • table of active products, [448]
  • rate of change of, [458]
  • life of, [458]
  • radium probable product of, [459] et seq.
  • amount of radium in, [460] et seq.
  • amount of, in radio-active minerals, [461]
  • growth of radium in, [463]
  • conservation of radio-activity of, [469]
  • total emission of energy from 1 gram of, [475]
  • possible causes of disintegration of, [486] et seq.
• Uranium X
  • separation of, by Crookes, [219]
  • separation of, by Becquerel, [219]
  • decay of activity of, [223]
  • recovery of activity of, [223]
  • theory to explain production of, [224] et seq.
  • material nature of, [226]
  • explanation of decay of activity of, [229]
  • changes in, [346] et seq.
  • radiations from, [347] et seq.
  • method of measurement of radiations from, [347]
  • effect of crystallization on activity of, [349]
  • diffusion of, [350]
• Velocity
  • of ions in electric field, [42] et seq.
  • difference between, of positive and negative ions, [43] et seq.
  • of β particle or electron, [126] et seq.
  • variation of mass of electron with, [127]
  • of α particle, [148]
  • of transmission of carriers of excited activity, [320] et seq.
  • of ions in atmosphere, [528]
• Villard
  • discovery of γ rays from radium, [179]
  • alteration of X ray screen with time, [205]
  • activity produced by cathode rays, [530]
• Vincenti and Levi Da Zara
  • radium emanation in spring waters, [516]
• Voller
  • variation of activity of radium with concentration, [467]
• Volume
  • of radium emanation, calculation of, [289]
  • decrease of, of radium emanation, [290]
• Walker, G. W.
  • theory of electrometer, [90]
• Walkhoff
  • action of radium rays on skin, [216]
• Wallstabe
  • diffusion of radium emanation into liquids, [276]
• Water
  • emanation from, [510] et seq.
  • decay of activity of emanation from, [511] et seq.
• Water-falls
  • amount of excited activity produced at Niagara, [520]
  • electrification produced near, [520]
• Watts, Marshall
  • atomic weight of radium, [18]
• Weichert
  • velocity of cathode rays, [76]
• Weight
  • loss of by radio-elements, [473]
  • attempts to measure loss of in radium, [474]
• Wheeler and Bumstead
  • diffusion of radium emanation, [273]
  • emanation from surface water and the soil, [512], [522]
  • identity of emanation from soil with radium emanation, [512], [522]
• Whetham
  • effect of valency of ion on colloidal solutions, [215]
  • production of radium from uranium, [463]
• Wiedemann
  • thermo-luminescence, [207]
• Wiedemann and Schmidt
  • thermo-luminescence, [207]
• Wien
  • value of e/m for canal rays, [78]
  • positive charge of canal rays, [78]
  • amount of charge carried by β rays, [124]
• Willcock, Miss and Hardy
  • coloration of iodoform solution by radium rays, [214]
• Willemite
  • phosphorescence of, under radium rays, [203]
  • use of, to show condensation of emanation, [279]
• Willows and Peck
  • action of radium rays on spark, [208]
• Wilson, C. T. R.
  • ions as nuclei of condensation, [47] et seq.
  • difference between positive and negative ions as condensation nuclei, [49]
  • equality of charges carried by positive and negative ions, [50]
  • construction of electroscope, [86], [88]
  • natural ionization of air in vessels, [501]
  • radio-activity of rain and snow, [505], [506]
  • loss of charge in closed vessels, [531] et seq., [534]
  • presence of ions in dust-free air shown by condensation, [533]
  • number of ions produced per c.c., [533]
  • effect of pressure and nature of gas on ionization in sealed vessels, [534]
• Wilson, H. A.
  • charge on ion, [51]
• Wilson, W. E.
  • radium in sun, [491]
• Wölfl, Hofmann and Gonder
  • properties of radio-active lead, [27], [413]
• Wood, A.
  • radio-activity of ordinary materials, [540]
• Zara, Levi Da and Vincenti
  • radium emanation in spring waters, [516]
• Zeeman
  • action of magnetic field on light, [77]
• Zeleny
  • velocity of ions, [42] et seq.
  • difference of velocity of ions, [45]
  • potential gradient between electrodes, [65]
• Zerban and Hofmann
  • connection of activity of thorium with uranium, [29]
• Zinc Sulphide
  • scintillations produced in by α rays, [158]
  • cause of luminosity of, [160], [549]

CAMBRIDGE: PRINTED BY JOHN CLAY, M.A. AT THE UNIVERSITY PRESS.