The Development of the New Radiography

We might expect from Nikola Lesia the most intelligent discussion of the new Röntgen rays, but we were not prepared for his announcement in the last week's Electrical Review. He says he is now producing strong. shadow pictures at a distance of forty feet, and he finds it necessary to guard the plates in his photographic department on the floor above, and sixty feet away, from being spoiled by long exposure to strong rays. He confesses himself amazed by the astonishing power of this radiation, especially as he sees the certitude of augmenting the effects at least tenfold. These effects on a sensitive plate at so great distance he obtains by the use of a bulb with a single terminal, which permits the use of practically any desired potential, and the attainment of extraordinary speeds of the projected particles; for he adopts the theory, not yet generally accepted, that the action is not that of waves of a certain sort of light, but that of actual atoms or ions projected at enormous speed right through glass, wood or metals.

We owe to Mr. Tesla also the proof that the Röntgen rays can be partially reflected, and he has succeeded in obtaining radiographs with reflected rays. He was able to reflect about two per cent. of the rays from a thick glass, these reflected rays being made to pass through a copper tube, and then give a clear and sharp shadow.

But most surprising of all his statements is that which he offers in proof that the Röntgen phenomena are caused by moving material particles, like those supposed in Newton's corpuscular theory of light. He gives the following experiment:

"If we attach a fairly exhausted bulb containing an electrode to the terminal of a disruptive coil, we observe small streamers breaking through the sides of the glass. Usually such a streamer will break through the seal and crack the bulb, whereupon the vacuum is impaired. But, if the seal is placed above the terminal, or if some other provision is made to prevent the streamer from passing through the glass at that point, it ofter occurs that the stream breaks out through the side of the bulb, producing a fine hole. Now, the extraordinary thing is that, in spite of the connection to the outer atmosphere, the air cannot rush into the bulb as long as the hole is very small. The glass at the place where the rupture is may grow very hot, to such a degree as to soften; but it will not collapse, but rather bulge out, showing that a pressure from the inside greater than that of the atmosphere exists. On frequent occasions I have observed that the glass bulges out, and the hole, through which the streamer rushes out, becomes so large as to be perfectly distinguishable to the eye. As the matter is expelled from the bulb, the rarefaction increases, and the streamer becomes less and less intense, whereupon the glass closes again, hermetically sealing the opening. Here we have positive evidence that matter is being expelled through the walls of the glass."

In the rapid development, by the concurrent labors of hundreds of students, of the discovery of Professor Röntgen, we see the advantage which comes, in science, from that fine and generous ambition which leads scholars to hasten to give to the world the results of their discoveries, that others may make applications and improvements. Professor Ramsay, who was associated with Lord Rayleigh in the discovery of argon last year, has suggested that a certain deference be paid to those who first announce a new discovery, by consulting them and getting their permission before others publish on the subject. This would be as foolish as it is impracticable. The analogy of patents, which he adduces, does not tell in favor of his claim. Every improvement on a patent is itself patentable. The honor which the discoveries of argon and the x rays have earned will not be diminished but rather enhanced by every new development of knowledge to which it gives occasion.