54. Relation of Vacuum to Phosphorescence. CROOKES 55. Phosphorescence of Objects within CROOKES Discharge Tube. 56. Darkness and Luminosity in the Arms of CROOKES a V Tube. 57. Cathode Rays Rectilinear within the CROOKES Discharge Tube. 58. Shadow Cast within the Discharge Tube. CROOKES 58_a_. Mechanical Force of Cathode Rays. Wheel CROOKES Caused to Rotate. 59. Action of Magnet upon Cathode Rays in CROOKES Discharge Tube. 60. Mutual Repulsion of Cathode Rays in CROOKES Discharge Tube. 61. Heat of Phosphorescent Spot. CROOKES 61_a_. Theoretical Considerations of Thomson (Kelvin). 61_b_, Velocity of Cathode Rays. THOMSON, J. J. page 46. 61_b_, Cathode Rays Charged with Negative PERRIN page Electricity. 47. 61_c_, Zeugen’s Photograph of Mt. Blanc Not Due to Cathode Rays. 62. Phosphorescence of Particular Chemicals GOLDSTEIN by Cathode Rays. 63. Spectrum of _Post_-phosphorescence of KIRN Discharge Tube Compared with that of Red-hot Metals. 63_a_. Chemical Action on Photographic Plate DE METZ by Cathode Rays Inside of Discharge Tube. 63_b_. The Passage of Cathode Rays through HERTZ Thin Metal Plates within the Discharge Tube (no. § 64). CHAPTER VI § 65, Cathode Rays Outside of the Discharge LENARD top of Tube whose Exit is an Aluminum page Window. A Glow Outside of the Window. 53. 65., Properties of Cathode Rays in Open Air. LENARD end of page 53. 66. Phosphorescence by Cathode Rays Outside LENARD of the Discharge Tube. 66_a_. Transmission Tested by Phosphorescence. 67. The Aluminum Window a Diffuser of LENARD Cathode Rays. 68. Transmission of External Cathode Rays LENARD through Aluminum and Thinly Blown Glass. 69. Propagation of External Cathode Rays. LENARD Turbidity of Air. 70. Photographic Action by External Cathode LENARD Rays and at Points beyond the Glow. No Other Chemical Power Probable. Shadows of Objects by Light and by External Cathode Rays Compared. No Heat Produced by External Cathode Rays. 71. External Cathode Rays and the Electric LENARD Spark Distinguished. Aluminum Window Not a Secondary Cathode.