Röntgen rays

“ The rays which travel furthest in the air are those most absorbed by the aluminium. There is therefore a great similarity between the absorbable α-rays of radium and the rays of polonium.
The deflected β-rays and the undeflected penetrating γ-rays are, on the contrary, of a different nature. The experiments, notably of MM. Meyer and von Schweidler, clearly show that, considering the radiation of radium as a whole, the penetrating power of this radiation increases with the thickness of the material traversed, as is the case of Röntgen rays. ”

“ We only know it is a fact.
All these ether rays may produce heat. The high-frequency rays affect the photographic sensitive plate, and also produce another effect that is of especial interest in connection with the study of the Röntgen rays. They have the power of exciting a peculiar luminosity, or light, in certain substances, which are for that reason called fluorescent.
Electrical discharges in vacuum tubes have long been known as sources of radiations which produce heat and affect the eye. ”

“ It will be seen that the Röntgen rays and their marvellous practical possibilities are still in their infancy. The first successful modification of the action of the rays so that the varying densities of bodily organs will enable them to be photographed, will bring all such morbid growths as tumors and cancers into the photographic field, to say nothing of vital organs which may be abnormally developed or degenerate. ”

“ According to the theory of Stokes, J. J. Thomson and Weichert, Röntgen rays are transverse pulses set up in the ether by the sudden arrest of the motion of the cathode particles on striking an obstacle. The more sudden the stoppage the shorter is the pulse, and the rays, in consequence, have greater power of penetrating matter. In some recent experiments Barkla found that the secondary rays set up by the Röntgen rays, on striking an obstacle, vary in intensity with the orientation of the vacuum tube, showing that the Röntgen rays exhibit the property of one-sidedness or polarization. ”

“ They resemble Röntgen rays in their great penetrating power and in their absence of deflection in a magnetic field. Earlier experiments seemed to indicate an important difference between the action of γ and X rays. It is well known that ordinary X rays produce much greater ionization in gases such as sulphuretted hydrogen and hydrochloric acid gas, than in air, although the differences in density are not large. For example, exposed to X rays, sulphuretted hydrogen has six times the conductivity of air, while with γ rays the conductivity only slightly exceeds that of air. ”

“ Amongst other theories which ascribe magnetic storms to direct solar action may be mentioned that of Kr. Birkeland, [45] who believes the vehicle to be cathode rays. Ch. Nordmann [46] similarly has suggested Röntgen rays. Supposing the sun the ultimate source, it would be easier to discriminate between the theories if the exact time of the originating occurrence could be fixed. For instance, a disturbance that is propagated with the velocity of light may be due to Röntgen rays, but not to Arrhenius’s particles. ”

“ It is curious that the part of the eye which is transparent to the light, and through which light passes to reach and affect the optic nerve, is nearly opaque to the Röntgen rays. Vision by means of these rays would therefore be impossible, even if the optic nerve were sensitive to them.
But suppose these rays could excite vision. What should we see? Holding a purse between the eye and a Röntgen ray source, we should see the coins within it. If a person stepped in the path of the ray we should see his bony skeleton. ”

“ Thus the production of Röntgen rays, regarded as consisting of very short and irregular electromagnetic impulses, is traced to the impacts of the electrons of the cathode-rays against the anti-cathode, and the lines of an emission spectrum indicate the existence in the radiating body of as many kinds of regular vibrations, the knowledge of which is the ultimate object of our investigations about the structure of the spectra. ”

“ Various Effects and Applications of the Ionising Action of the Rays Emitted by Radio-active Substances. The rays of the new radio-active substances have a strongly ionising action upon air. By the action of radium the condensation of supersaturated water vapour can be easily induced, just as happens by the action of cathode rays and Röntgen rays. ”

“ The velocity of these rays is independent of the intensity of the primary Rontgen rays, but depends upon the “hardness” of the rays; it seems also to be independent of the nature of the matter exposed to the primary rays. The velocity of the cathodic rays increases as the hardness of the primary Rontgen rays increases. Innes (Proc. Roy. Soc. 79, p. 442) measured the velocity of the cathodic radiation excited by the rays from Rontgen tubes, and found velocities varying from 6-2 X 1o9cm./sec. to 8- 3X 109 cm./sec. according to the hardness of the rays given out by the tube. ”

“ The method thus breaks down as we approach the most interesting part of the atom.
I think, however, that we may hope before long to have at our disposal methods by which we can produce and investigate Röntgen rays of a much softer type than those hitherto used. Röntgen rays are usually generated by shooting rapidly moving electrons against a solid target; the greater the speed of the electrons the harder are the rays they produce. The softest characteristic radiation yet detected is that from aluminium ”

“ It was in company with this stream of violet rays, known as the brush discharge, that the doctor conceived the invisible Röntgen rays to be projected at each spark discharge around the plate; and presently, when the photographic plate was developed, it was found that his conception was based on fact. For there, dim in outline, but unmistakable, were shadow pictures of the ten letters which stand as historic, since they were probably the first shadow pictures in the world taken without any bulb or vacuum tube whatever. ”

“ It was left, however, for Professor Röntgen 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 Röntgen rays are not deflected by a magnet, indicating a very essential difference, while their range and penetrative power are incomparably greater. ”

“ All one sees is a few tiny crystals, or perhaps a few specks of whitish-looking powder, glowing in the dark with a faint phosphorescent light similar to that sometimes emitted by a piece of decaying fish.
The Radiations are of three kinds, comparable with those of the vacuum tube: Alpha-rays are heavy particles, positively charged, similar to the canal rays; Beta-electrons, negative like cathode rays; Gamma-rays resemble Röntgen rays. They penetrate matter to different degrees, behave differently under the action of a magnetic field, but under ordinary circumstances travel in straight lines. ”

“ The process of taking a shadowgraph may therefore be conducted in broad daylight, which is under certain conditions a great advantage, though the sensitiveness of plates exposed to Röntgen rays entails special care being taken of them when they are not in use. In the early days of X-radiography an exposure of some minutes was necessary to secure a negative, but now, thanks to the improvements in the tubes, a few seconds is often sufficient.
The discovery of the X-rays is a great discovery, because it has done much to promote the noblest possible cause, the alleviation of human suffering. ”

“ The discovery of the X rays—a discovery which physicists no doubt consider as the logical outcome of researches long pursued by a few scholars working in silence and obscurity on an otherwise much neglected subject—seemed to the public eye to have inaugurated a new era in the history of physics. If, as is the case, however, the extraordinary scientific movement provoked by Röntgen's sensational experiments has a very remote origin, it has, at least, been singularly quickened by the favourable conditions created by the interest aroused in its astonishing applications to radiography. ”

“ It was past eleven o'clock when I got home; my servant, Silva by name, a Hungarian, was waiting up for me. I told him to go to bed, and went straight to my laboratory. I was making certain experiments of an interesting nature, and in particular was anxiously developing some photographs which I had just taken by means of the Röntgen rays. The new discovery was now the craze of the whole scientific world, and I, of course, with other men of science, was bitten with it. I had several vacuum tubes by me, and all the necessary apparatus for making the rays. ”

“ The discovery that each element gives out a characteristic radiation (or, as still more recent work indicates, a line spectrum of characteristic radiation) is one of the utmost importance. It gives us, for example, the means of getting homogeneous Rbntgen radiation of a perfectly definite type: it is also of fundamental importance in connexion with any theory of the Rontgen rays. We have seen that there is no evidence of refraction of the Rontgen rays ”

“ Even in air the rays appear to be rapidly absorbed, so that an extremely powerful apparatus is required for producing effects at any distance. Air seems to behave toward the Röntgen rays much as fog behaves to light, and it seems unlikely that effects can be procured at any great distance, perhaps not more than one hundred feet from the source. ”

“ In daylight objects become visible by means of the light which falls upon them and is reflected to the eye. This brings out the detail of the visible surface. But the Röntgen rays are scarcely at all reflected, and even if they produced vision, objects would become visible only as they intercepted the rays. They would not be illuminated as they are illuminated by rays of light, and only outlines, therefore, would be seen. ”

“ We know that small particles moving with very high speeds do exist, that they possess considerable powers of penetrating solids, though not, as far as we know at present, to an extent comparable with that postulated by Le Sage; and we know that the energy lost by them as they pass through a solid is to a large extent converted into a still more penetrating form of radiation, Röntgen rays. ”

“ Just as the distance between adjacent lines of a grating must be comparable to the wave length of light for a spectrum to be formed, a periodic structure with a grating space of their very much shorter wave length is necessary to diffract X-rays. Such a structure is altogether too fine to be made by human tools. Nature, however, has already prepared it for man’s use. The distance between the atoms of a crystal is just right to make it an excellent X-ray grating, and Laue had no difficulty in obtaining diffraction patterns when Röntgen rays were passed through a block of zincblende. ”

“ Ionization by Collision.—When the ionization of the gas is produced by external agents such as Röntgen rays or ultra-violet light, the electric field produces a current by setting the positive ions moving in one direction, and the negative ones in the opposite; it makes use of ions already made and does not itself give rise to ionization. In many cases, however, such as in electric sparks, there are no external agents to produce ionization and the electric field has to produce the ions as well as set them in motion. ”

“ Finally, the century, shortly before its departure, has accomplished in the physical domain one of its most valuable feats by the discovery of the X or Röntgen rays, which permit our eye to penetrate to the innermost depths of objects hitherto regarded as opaque, and thereby make almost true the marvels of the Arabian Nights. Not less wonderful and unexpected is the success, likewise belonging to very recent time, attained by the experiments in liquefying and solidifying gases, like oxygen, nitrogen, carbonic acid, chlorine gas, and atmospheric air. ”

“ Raymond suggested, "as the wireless message enters the receiver? In these days of wireless telegraphy, of the Röntgen rays, and of the still more wonderful Becquerel rays, I don't see how we are going to deny the possibility of telepathy too."
"Oh, we live in a world of marvellous possibilities," Puivert conceded. "And no one can say what hitherto undiscovered powers and properties are not lying close at hand. ”

“ Not only has electricity been applied to transportation and the development of light and power; but the latest discovery by Professor Röntgen of the X rays seems destined, possibly, not only to revolutionize our ideas of radiation in all its forms on the scientific side, but also on the practical side to be of use in the domain of medicine. It is, therefore, with great pleasure that I accede to the request of the editor of this Magazine to state briefly what has been achieved in the department of medicine up to the present time. ”

“ They are allowed to fall (still invisible) on to a photographic plate, when a picture like an ordinary permanent photograph is obtained by their chemical action, or they may be made to exert their phosphorescence-producing power on a glass plate covered with a thin coating of a phosphorescent salt such as barium platino-cyanide, when a temporary picture in light and shade is seen.
The rays discovered by Röntgen were known as the X-rays, because their exact nature was unknown. ”

“ Cavor's search was a substance that should be "opaque"—he used some other word I have forgotten, but "opaque" conveys the idea—to "all forms of radiant energy." "Radiant energy," he made me understand, was anything like light or heat or those Röntgen rays there was so much talk about a year or so ago, or the electric waves of Marconi, or gravitation. All these things, he said, radiate from centres and act on bodies at a distance, whence comes the term "radiant energy." Now almost all substances are opaque to some form or other of radiant energy. ”