The positive charges were of the order of magnitude of the negative charges previously obtained. The Faraday's cylinder is then invariably charged with positive electricity. The protecting cylinder E F G H with its opening b fulfilled these conditions, and this time I therefore employed it as the kathode, the electrode N being the anode. This electricity could then act upon a Faraday's cylinder inside the kathode. In order to verify this hypothesis, it is sufficient to use a hollow kathode pierced with a small opening by which a portion of the attracted positive electricity might enter. I believe that I have found them in the very region where the kathode rays are formed, and that I have established the fact that they travel in the opposite direction, and fall upon the kathode. (3) The kathode rays being negatively charged, the principle of the conservation of electricity drives us to seek somewhere the corresponding positive charges. I have not finished this investigation, but I shall give an idea of the order of magnitude of the charges obtained when I say that for one of my tubes, at a pressure of 20 microns of mercury, and for a single interruption of the primary of the coil, the Faraday's cylinder received a charge of electricity sufficient to raise a capacity of 600 C. ![]() The quantity of electricity which these rays carry can be measured. In short, the Faraday's cylinder became negatively charged when the kathode rays entered it, and only when they entered it the kathode rays are then charged with negative electricity. When this was excited, the kathode rays, becoming deflected, no longer passed into the Faraday's cylinder, and this cylinder was then not charged it, however, became charged immediately the electromagnet ceased to be excited. The vacuum tube could be placed between the poles of an electro-magnet. This cylinder invariably became charged with negative electricity. The electrode N served as kathode: the anode was formed by the protecting cylinder E F G H: thus a pencil of kathode rays passed into the Faraday cylinder. in front of F G, was placed an electrode N. A metal thread soldered at S connects this cylinder with an electroscope.Į F G H is a second cylinder in permanent communication with the earth, and pierced by two small openings at b and c: it protects the Faraday's cylinder from all external influence. It is this tube which plays the part of a Faraday's cylinder. A B C D is a tube with an opening a in the centre of the face B C. For this purpose I employed the vacuum tube represented in Fig. ![]() I therefore caused the kathode rays to pass into a Faraday's cylinder. (2) For that purpose I had recourse to the laws of induction, by means of which it is possible to detect the introduction of electric charges into the interior of a closed electric conductor, and to measure them. Its adherents suppose that the kathode rays are negatively charged as far as I know, this electrification has not been established and I first attempted to determine whether it exists or not. This latter hypothesis has suggested to me some experiments which I will now briefly describe without for the moment pausing to inquire whether the hypothesis suffices to explain all the facts at present known, and whether it is the only hypothesis that can do so. Thomson, that these rays are formed by matter which is negatively charged and moving with great velocity, and on this hypothesis their mechanical properties, as well as the manner in which they become curved in a magnetic field, are readily explicable. ![]() It is easily understood that such rays may have a rectilinear path, excite phosphorescence, and effect photographic plates. Some physicists think with Goldstein, Hertz, and Lenard, that this phenomenon is like light, due to vibrations of the ether 1 or even that it is light of short wavelength. (1) Two hypothesis have been propounded to explain the properties of the kathode rays. Translation appeared in: Nature, Vol 53, p. Read before the Paris Academy of Sciences Perrin and Cathode Rays NEW EXPERIMENTS ON THE KATHODE RAYS
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