VIII CONTENTS. 



MISCELLANEOUS EXPERIMENTS. Page. 



38. Experiments to detect the region of positive ions. Table 16; fig. 16 48 



39. Radium within the fog chamber. Sealed tubes. Table 17 50 



40. Distance effect. Table 1 8 51 



41. Attempt to calibrate the fog chamber with five separate sealed tubelets of 



radium. Tables 18 and 19 51 



CHAPTER IV. The Standardization of the Fog Chamber by A id o] Thomson's 



Electron . 



THE CONSTANT e, EXPRESSED IN TERMS OF VELOCITIES OF THE IONS. 



42. Advantages 54 



43. Plate. Fig. 17 54 



44. Cylinder. Fig. 18 55 



45. The same. Preliminary data. Table 20 56 



46. The same. Wires surrounded by earthed pipes 57 



47 . Conclusion 58 



THOMSON'S CONSTANT e, EXPRESSED IN TERMS OF THE DECAY CONSTANT 



OF IONS WITHIN THE FOG CHAMBER. 



48. Introductory 59 



49. Electrical condenser fog chamber 59 



50. Auxiliary condenser 60 



5 1 . Methods 6 1 



52. Data disregarding external gamma rays. Table 21 61 



53. Further data. Table 22 63 



CHAPTER V. The Electron Method o) Standardizing the Coronas of Cloudy 

 Condensation in Terms of the Velocities of the Ions. 



54. Introductory 65 



55. Apparatus. Fig. 19 65 



56. Auxiliary electrical condensers 66 



57. Methods pursued 67 



58. Data. High ionization currents. Table 23 69 



59. The same. Coronas 70 



60. The same. Summary. Figs. 20 and 21 71 



61. Data. Moderate ionization. Electrical currents 72 



62. The same. Coronas 72 



63. The same. Summary. Figs. 22 and 23 72 



64. Data. Small ionizations. Electric currents 74 



65. The same. Coronas 74 



66. The same. Summary. Figs. 24 and 25 74 



67. Conclusion 75 



CHAPTER VI. Electrometric Measurement of Voltaic Potential Difference 

 between the Conductors of the Condenser Separated by an Ionized 

 Medium. 



68. Introductory. Fig. 26 76 



69. Theory 78 



70. Data. Origin of the electrometer current. Fig. 27 80 



71. Aluminum core charged with radium tubelets. Table 24; fig. 28 82 



72. Results. Ionization and voltaic contact potential difference 82 



73. Voltaic contacts: aluminum-zinc, aluminum-copper, aluminum-aluminum. 



Table 25 ; fig. 29 82 



74. Further experiments and conclusion 83 



