Contents xv 



PAGE 



The Aurora and the Magnetic Needle . .261 



Miscellaneous Theories of the Aurora 261 



Ignis Lambens and Ignis Fatuus 263 



Nature of the phenomenon 263 



Records of Ignis Lambens 266 



Relation to Electricity 268 



The " Electric Light " and " Electric Fire " . . 269 



Virtues and Effluvia 269 



Otto von Guericke 270 



The Barometer Light or the Mercurial Phosphor . 271 



Francis Hauksbee and Evacuated Globes .... 276 



The Rise of Electrical Knowledge 281 



William Watson and Electricity in Vacuo .... 287 



Wilson, Smeaton, and Canton 289 



The Relation of the " Electric Light " to other Lumi- 

 nescences 290 



From Joseph Priestley to Michael Faraday . . . 293 



Julius Pliicker and Later Research 296 



Afterglow in Gases 301 



Electrodeless Discharges 302 



New Types of Rays 303 



Survey 304 



Chapter VIII. Phosphorescence 305 



Introduction . 305 



Early Records 305 



The Bolognian Phosphor 306 



Cascariolo, Galileo, and LaGalla 306 



Pierre Potier 308 



Ovidio Montalbani 309 



Fortunio Liceti 311 



Athanasius Kircher 312 



Nicolai Zucchi and Mid-Seventeenth-Century Obser- 

 vations 313 



Count Marsigli and Other Italians 315 



German Interest 316 



Nicolas Lemery and French Opinion 317 



Phosphorus Hermeticus (Baldewein and Mentzel) . . 321 



Friedrich Hoffman and Calcium Sulphide phosphor . 323 



De Mairan and Cohausen 323 



Bartholomeo Beccari and Co-workers 324 



