Certain it was that something was doing this work.  Certain it was that it was not light.  Highly probable it was that it was not any form of electricity, for glass is impermeable to the electrical current.  Certain it was that it was not sound, for there was no noise or atmospheric agitation to produce such a result.  In a word, it was demonstrated then and there that a hitherto unknown, subtle and powerful agent had been discovered, the applications of which might be of almost infinite range and interest.

Professor Roentgen soon announced his discovery to the Physico-Medical Society of Wuerzburg.  It was at the December meeting of this body that the new stage in human progress was declared.  The news was soon flashed all over the world, and scientific men in every civilized country began at once to experiment with the cathode light—­if light that might be called that lighted nothing.

In Roentgen’s announcement he stated that there had been by the scientists Hertz and Lenard, in 1894, certain antecedent discoveries from which his own might in some sense be deduced.  There was, however, a great difference between the discovery made by Roentgen and anything that had preceded it.  His stage of progress in knowledge was this, that during the discharge of one kind of rays of force from the cathode pole in a Crookes tube another kind of rays are set free, which differ totally in their nature and effects from anything hitherto known.  It is this fact which has indissolubly connected the name of Konrad Roentgen with that great bound in scientific knowledge which seems likely to modify nearly all the other scientific knowledge of mankind.

Everywhere, in the first months of 1896, the experimenters went to work to verify and apply the discovery of the German philosopher.  It was at once discerned that the new force, since it would freely traverse opaque bodies and produce afterward chemical changes on sensitized surfaces similar to those ordinarily produced by light, might be used for delineating (we can hardly say photo graphing) the interior outlines and structure of opaque bodies!

On this line of experimentation the work at once began, and with remarkable success.  Roentgen himself was the first man in the world to obtain, as if by photography, the invisible outline of objects through opaque materials.  He soon obtained a delineation of the bones of a living hand through the flesh, which was only dimly traced in the resulting picture.  In like manner coins were delineated through the leather of pocketbooks.  Other objects were pictured through intervening plates of metal or boards of wood.  The possibility of discovering the visible character of invisible things, and even of seeing directly through opaque materials into parts where neither light nor electricity can penetrate, was fully shown.