demand.

It transpired, in the course of inquiry, that the professor is
a married man and fifty years of age, though his eyes have the
enthusiasm of twenty-five. He was born near Zurich, and educated
there, and completed his studies and took his degree at Utrecht. He
has been at Würzburg about seven years, and had made no discoveries
which he considered of great importance prior to the one under
consideration. These details were given under good-natured protest, he
failing to understand why his personality should interest the public.
He declined to admire himself or his results in any degree, and
laughed at the idea of being famous. The professor is too deeply
interested in science to waste any time in thinking about himself. His
emperor had _fêted_, flattered, and decorated him, and he was loyally
grateful. It was evident, however, that fame and applause had small
attractions for him, compared to the mysteries still hidden in the
vacuum tubes of the other room.

[Illustration: BONES OF A HUMAN FOOT PHOTOGRAPHED THROUGH THE FLESH.

From a photograph by A.A.C. Swinton, Victoria Street, London.
Exposure, fifty-five seconds.]

"Now, then," said he, smiling, and with some impatience, when the
preliminary questions at which he chafed were over, "you have come to
see the invisible rays."

"Is the invisible visible?"

"Not to the eye; but its results are. Come in here."