THE ROENTGEN OR X-RAYS.
Geissler Tubes. Vacuum Tubes of Crookes, Hittorf, and Lenard. The
Cathode Ray. Roentgen’s Great Discovery in 1895. X-Ray Apparatus.
Salvioni’s Cryptoscope. Edison’s Fluoroscope. The Fluorometer. Sun-
burn from X-Rays. Uses of X-Rays.