ory," 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
peculiar black line across the paper."

"What of that?"

"The effect was one which could only be produced, in ordinary
parlance, by the passage of light. No light could come from the tube,
because the shield which covered it was impervious to any light known,
even that of the electric arc."

"And what did you think?"

"I did not think; I investigated. I assumed that the effect must have
come from the tube, since its character indicated that it could come
from nowhere else. I tested it. In a few minutes there was no doubt
about it. Rays were coming from the tube which had a luminescent
effect upon the paper. I tried it successfully at greater and greater
distances, even at two metres. It seemed at first a new kind of
invisible light. It was clearly something new, something unrecorded."

"Is it light?"

"No."

"Is it electricity?"

"Not in any known form."

"What is it?"

"I don't know."

And the discoverer of the X rays thus stated as calmly his ignorance
of their essence as has everybody else who has written on the
phenomena thus far.

"Having discovered the existence of a new kind of rays, I of course
began to investigate what they would do." He took up a series of
cabinet-sized photographs. "It soon appeared from tests that the rays
had penetrative power to a degree hitherto unknown. They penetrated
paper, wood, and cloth with ease; and the thickness of the substance
made no perceptible difference, within reasonable limits." He showed
photographs of a box of laboratory weights of platinum, aluminium, and
brass, they and the brass hinges all having been photographed from a
closed box, without any indication of the box. Also a photograph of
a coil of fine wire, wound on a wooden spool, the wire having been
photographed, and the