A Useful Scientific Invention !

This is in a very old autograph book that has been in our family for many years. Drawn by an unknown person, in 1904, I was fascinated to find out that in 1895, X-Rays were accidently discovered by a German physicist, Wilhelm Conrad Rontgen. He was working with a cathode ray tube and found that when a high voltage was applied, the tube produced a fluorescent glow. He concluded that a new type of ray was being emitted, which could pass through most substances but not bones or metal. He then made the first X-Ray of his wife's hand. So this sketch was drawn not long after, a talking point no doubt. I like the idea of the mouse checking up on the whereabouts of the cat !