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."