photographic results beyond. It was left, however, for Professor
Roentgen to discover that during the discharge quite other rays are set
free, which differ greatly from those described by Lenard as cathode
rays. The most marked difference between the two is the fact that
Roentgen rays are not deflected by a magnet, indicating a very essential
difference, while their range and penetrative power are incomparably
greater. In fact, all those qualities which have lent a sensational
character to the discovery of Roentgen's rays were mainly absent from
those of Lenard, to the end that, although Roentgen has not been working
in an entirely new field, he has by common accord been freely granted
all the honors of a great discovery.

Exactly what kind of a force Professor Roentgen has discovered he does
not know. As will be seen below, he declines to call it a new kind of
light, or a new form of electricity. He has given it the name of the X
rays. Others speak of it as the Roentgen rays. Thus far its results only,
and not its essence, are known. In the terminology of science it is
generally called "a new mode of motion," or, in other words, a new
force. As to whether it is or not actually a force new to science, or
one of the known forces masquerading under strange conditions, weighty
authorities are already arguing. More than one eminent scientist has
already affected to see in it a key to the great mystery of the law of
gravity. All who have expressed themselves in print have admitted, with
more or less frankness, that, in view of Roentgen's discovery, science
must forthwith revise, possibly to a revolutionary degree, the long
accepted theories concerning the phenomena of light and sound. That the
X rays, in their mode of action, combine a strange resemblance to both
sound and light vibrations, and are destined to materially affect, if
they do not greatly alter, our views of both phenomena, is already
certain; and beyond this is the opening into a new and unknown field of
physical knowledge, concerning which speculation is already eager, and
experimental investigation already in hand, in London, Paris, Berlin,
and, perhaps, to a greater or less extent, in every well-equipped
physical laboratory in Europe.

This is the present scientific aspect of the discovery. But, unlike most
epoch-making results from laboratories, this discovery is one which, to
a very unusual degree, is within the grasp of the popular and
non-technical imag