ILLUSTRATIONS. 



FIG. PAGE 



28 (6). RADIUM CHLORIDE, PHOTOGRAPHED BY THE LIGHT OF ITS 



PHOSPHORESCENCE 98 



29 (a). AN ELECTROSCOPE, CHARGED 99 



29 (6). THE SAME ELECTROSCOPE DISCHARGED BY RADIUM 100 



30. M. BECQUEREL AND THE EXPERIMENT WITH THE MAGNET 101 



31. MAGNETIC DEVIATION OF THE BECQUEREL RAYS 102 



32. RADIOGRAPH SHOWING THE PENETRATIVE POWER OF 



RAYS FROM RADIUM 102 



33. BECQUEREL RAYS CONSIST OF AT LEAST Two KINDS 103 



34. ANOTHER PROOF 103 



35. SECTION OF CROOKE'S SPINTHARISCOPE 106 



36. PHOSPHORESCENCE INDUCED BY INDUCED RADIO-ACTIVITY 113 



37. CURIE'S EXPERIMENT PROVING THE EXISTENCE ^ OF AN 



EMANATION 114 



38 (a). CURIE'S ELECTROSCOPE FOR THE STUDY OF RADIO-ACTIVITY 117 



38 (6). DIAGRAMMATIC REPRESENTATION OF FIG. 38 (a) 117 



S9. CURVES SHOWING THE RATE OF RECOVERY OF THE RADIUM 



AND THE DECAY OF THE EMANATION 120 



40. THE SPECTRUM OF HELIUM 125 



41. CURVES SHOWING THE RATE OF RECOVERY OF THORIUM 



AND THE DECAY OF THORIUM X 127 



42. THE ARRANGEMENT OF Two CORPUSCLES 154 



43. THE ARRANGEMENT OF THREE CORPUSCLES 154 



44. THE CONFIGURATIONS ASSUMED BY FLOATING MAGNETS. . 156 



45. A CONTINUOUS AND A DISCONTINUOUS SPECTRUM 195 



46. PARTS OF THE SPECTRA OF BARIUM AND IRON 195 



47. FLUTINGS OF CARBON 196 



48. SERIES SPECTRA IN THE CLEVEITE GASES 196 



49. FRAUNHOFER'S LINES 198 



50. IRON SUN-SPOT LINES AT KENSINGTON CONFRONTED WITH 



IRON PROMINENCE-LINES AT PALERMO 202 



51. DIFFERENT RATES OF MOTION REGISTERED BY DIFFERENT 



IRON LINES 203 



52. DIAGRAM SHOWING THE DURATION OF ORGANIC EVOLU- 



TION COMPARED WITH INORGANIC EVOLUTION 215 



53. SPECTRA SHOWING AN INORGANIC DEVOLUTION 219 



54. THE PROGRESS OF A NEBULA TO A DARK STAR 223 



