VIII 



CHAPTER IV. 



EXPERIMENTS MADE WITH THE TERRELLA WITH THE SPECIAL PURPOSE 

 OF FINDING AN EXPLANATION OF THE ORIGIN OF THE 



POSITIVE AND NEGATIVE POLAR STORMS. Page 



Art. 108. Introductory 553 



STUDY OF RAYS OF GROUP A. 



,, 109. Experiment in which the Terrella had only a Vertical Screen 560 



no. Experiments in which the Terrella is surrounded by a Horizontal Screen 566 



in. Equatorial Rings of Light 569 



STUDY OF RAYS OF GROUP B. 



112. The Course of the Rays in the Polar Regions over the Terrella 572 



113. Experiments for determining the Tangential Component of the Polar Precipitation in Relation 



to the Surface of the Terrella 580 



114. On an Intimate Connection between Rays of the two Groups A and B 583 



,, 115. On the Size of the Polar Ring of Precipitation 591 



116. The Value of H . Q for the Helio-Cathode Rays 598 



117. Experiments for the Determination of the Situation of the Polar Zone of Precipitation in 



Various Positions of the Magnetic Axis 600 



1 1 8. Investigations Regarding the Angle formed by the Precipitated Rays with the Magnetic 



Lines of Force. Application to the Polar Aurora 603 



CHAPTER V. 



IS IT POSSIBLE TO EXPLAIN ZODIACAL LIGHT, COMETS' TAILS, AND 

 SATURN'S RING BY MEANS OF CORPUSCULAR RAYS? 



,, 119, 120, 121. Zodiacal Light 611 



122. Appendix. Expedition to Assouan and Omdurman 624 



123. Magnetic Registerings, the 9th April, 1911 629 



124. Comets' Tails . . 631 



125. Halley's Comet, May, 1910 639 



126. Meteorological Observations about the Time of the Transit of Halley's Comet, 1910 . . 647 



,, 127. The Saturnian Ring 654 



CHAPTER VI. 

 ON POSSIBLE ELECTRIC PHENOMENA IN SOLAR SYSTEMS AND NEBULAE. 



128. The Sun 661 



129. Experiments showing Analogies to Solar Phenomena 662 



130. Application of the Analogies to further Study of Celestial Phenomena 670 



131. The Worlds in the Universe 677 



132. Investigations of the Motion of Electric Corpuscles in the Field of an Elementary Magnet 



especially to find the Conditions for the Approach to Boundary-Circles 678 



133. Study of the Approach to Boundary Circles, when there is a Resistance in the Medium 686 



,, 134. Study of the Approach to Boundary-Circles, when the Charge of the Particles is variable 693 



n I 35- Study of the Approach to Boundary-Circles outside the Magnetic Equatorial Plane . . . 697 



136. Comparison of Boundary-Circles approached by Different Sorts of Corpuscles .... 706 



,, 137. Experiments made with the largest Vacuum-box with a Capacity of 1000 Litres . . . 709 



138. On the Charge of Metallic Particles ejected from a Cathode 716 



,, 139. On the Possible Density of flying Corpuscles in Space 720 



