The rays from the Röntgen eyes instantly penetrated the deeply hidden
purpose. "Oh, no," said he; "I can't let you make pictures of me. I
am too busy." Clearly the professor was entirely too modest to gratify
the wishes of the curious world.

"Now, Professor," said I, "will you tell me the history of the
discovery?"

[Illustration: COINS PHOTOGRAPHED INSIDE A PURSE.

From a photograph by A.A.C. Swinton, Victoria Street, London.]

"There is no history," he said. "I have been for a long time
interested in the problem of the cathode rays from a vacuum tube
as studied by Hertz and Lenard. I had followed theirs and other
researches with great interest, and determined, as soon as I had the
time, to make some researches of my own. This time I found at the
close of last October. I had been at work for some days when I
discovered something new."

"What was the date?"

"The eighth of November."

"And what was the discovery?"

"I was working with a Crookes tube covered by a shield of black
cardboard. A piece of barium platino-cyanide paper lay on the bench
there. I had been passing a current through the tube, and I noticed a