The early history of radiological physics: "a fourth state of matter".
D001610:Beta Particles / Q000266:history; D004560:Electricity / Q000266:history; D055590:Electromagnetic Phenomena / Q000266:history; D006283:Health Physics / Q000266:history*; D049671:History, 18th Century; D049672:History, 19th Century; D049673:History, 20th Century; D008163:Luminescent Measurements