Digest: Roentgen Ray Investigation

Saturday, May 2, 1896
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Mn 1. 1896- THE ELECTRICAL WORLD. 491 Rdnlgm Ray Invertigaiinru. TESLA. Elec. Kev., April on.-His investiga- tions with redection have confirmed his opinion that Volta‘s electric contact series in air are identical with the order of the metals arranged according to their power of reflection, the most electro-positive metal being the best reflector; platinum. is the poorest and sodium one of the best; this order is approximately the same as that with reference to their energies of combination with oxygen; should this be confirmed by other physicists, the following conclusions would be justified; first, that highly exhausted bulbs emit material streams which are reflected from metallic surfaces; second, these streams are formed of matter in some primary or elementary condition; third, the streams are probably the same agent which is the cause of the electromotive tension between metals in close proximity; fourth, every metal or conductor is more or less a source of such streams; fifth, these streams must be produced by some radiations which exist in the medium; sixth, streams resembling the cathodic must be emitted by the sun, and probably also by other sources of radiant energy; these conclusions are discussed in detail. He predicts that if a sensitive film is placed between a magnesium and a copper plate, a tnie Riintgen shadow picture would be obtained after a long exposure in the dark; he thinks it probable that there isa continuous supply of such radiations from the medium in some form, and that they come from the sun, from which he concludes that with very long exposures Rontgen shadow pictures could be obtained from all sources of radiant energy, provided the radiations are permitted first to impinge upon a metal or other body; he suggests that the lumps of matter composing a cathodic stream ln the bulb are broken up into small particles by impact against the walls of the tube and are thereby enabled to pass into the air; the difference between Riintgen and Lenard rays is that the particles composing the fonner are incomparably smaller and have a higher velocity, which he believes is thereason why they are not deflected by a magnet; he tried to find whether the deflected rays possessed distinctive features but could notice no difference; it is important to find out what becomes of the energy of these rays; his tests have confirmed R5ntgen‘s statement that the rays are incapable of raising the temperature of a body. He has increased the efficiency of the reflectors by providing separate successive layers for reflection, by making the reflector of thin sheets of metal or mica. He recalls a former experiment in which a brush or stream issu- ing from a single electrode rotated very rapidly due` to the carth‘s magnetism, and he thinks that perhaps the Lenard`and Riintgen streams also rotate under the action of the earth‘s magnetism, He does not favor the idea of vibrations approximating those of light and thinks that all these effects could be produced with steady electrical pressure like that from a battery, with the exclusion of all vibrations; he found no effect due to changes of the frequency although it was varied between wide limits; to obtain clear shadows it is very important to pass the rays through some tubular reflector which makes them approximately paral- lel; clearer pictures were obtained by using very thick films developed very slowly. He has succeeded in making the radiation more powerful and describes and illustrates his new form of apparatus in which the rays were made to pass through various' thicknesses of circu- lating oil; with this apparatus he claims to have obtained better results. By mixing a non-fluorescent powder with the fluorescent material for a screen he found that the general brightness was diminished, but that the shadows were sharper; the vertebral column could be seen quite clearly even in the lower part of the body, as also the outlines of the hip bones; he located the heart unmistakably, the background for which appeared to be brighter ; the bones of the hand could be seen very clearly through sheets of copper, iron and brass nearly one fourth of an inch thick, and through glass the rays seemed to pass with great freedom, one half aninch of glass hardly dimming the fluorescence; it appeared sometimes as if the bones and flesh were equally transparent to radiations passing through the oil; the motion of a hand could be clearly seen through the body; it is of advantage to detennine by means of the screen the proper distance at which an object should be placed before taking the photographic impression. The effect noticed by Prof. J. J. Thomson, that bodies traversed by these rays became conductors, was further investigated, but the conclusion could not be confirmed, and he (’l`Es|.A) claims that it is a further evidence of the existence of streams of matter, but not that the bodies become conductors in the common accept- ation of the term.