INDEX 



Hull, 144. 

 Humphreys, 145. 

 Hydrogen, arc in, 83. 



Intrinsic brightness of crater, 132. 

 lonization : 



by impact, 158. 



by hot solids, 159. 



at surface of cathode, 161, 162, 

 165, 



at surface of anode, 162, 168. 



of gas between electrodes, 171. 



by ultra-violet light, 172. 

 Ions: 



velocity of, 101, 176. 



definition of, 156. 



causes producing, 158. 



discharge of, to electrodes, 170. 

 Iron electrodes, 64. 

 Iron-titanium arc: 



characteristic curves for, 69. 



candle power of, 139. 



Jamin and Maneuvier, 114, 118. 

 Janet, 152. 

 Joubert, 107. 



Kayser, 144. 



Knipp, 92, 96, 97. 



Kuch and Retschinski, 100, 135. 



Kuch, Stark and, 81. 



Lamp, mercury vapor, 89. 

 Lange, Gertrude, 112. 

 Le Chatelier, 41. 

 Lecher, 24, 37, 46, 63, 66. 

 Lenard, 144. 



Length of arc: 



and candle power, 130. 



and potential difference, see Char- 

 acteristic curves. 

 Le Roux, 37, 106. 

 Liga, Corbino and, 37. 

 Light from arc: 



quality of, see Color. 



quantity of, see Candle power. 

 Luggin, 24, 28, 31, 37, 60, 163. 

 Luminous vapor from mercury arc, 



99. 

 Lummer and Pringsheim, 43. 



M 



McClelland, 177. 

 Magnetic field: 



carbon arc in, 6, 50. 



whistling arc in, 151. 

 Magnetite arc: 



characteristic curves for, 67. 



candle power of, 139, 140. 



ionization in, 180. 

 Mahlke, 9, 56. 



Malcolm and Simon, 15, 48, 64, 83. 

 Maneuvier, Jamin and, 114, 118. 

 Manufacture of carbons, 8. 

 Marchant, 133. 



Marchant, Duddell and, 22, 112. 

 Marks, 49. 

 Matthies, 179. 

 Matthews, 137. 



Mean free path of ions in arc, 173. 

 Mean spherical candle power, 128. 

 Mercury arc: 



discovery of, 88. 



commercial form of, 89. 



temperature of, 91. 



characteristic curves for, 93. 



pressure in, 94. 



cathode drop in, 96. 



