Electric ray

“ As the wave length of electrical radiation is very large compared with that of visible light, it may be thought that very large crystals, much larger than what occur in nature, would be required to produce polarisation of the electric ray. ”

“ When the deviated rays are convergent, the receiver is simply placed behind the shields, at the focus of the rays. But when the rays are parallel, the use of an objective (placed behind the first shield) gives very satisfactory results. As objectives I used ordinary glass lenses; knowing the index from my experiments, I was able to calculate the focal distance for the electric ray. ”

“ All good electrical conductors are opaque to electric radiation, and all good insulators or non-conductors are transparent.
Hence we see at once why metal sheets are opaque, and wood, wax, or glass transparent, to the electric radiation from the spark-balls.
We may go one step further. If we take some sheets of perforated zinc or wire gauze, or even a large packet of pins, or paper bag full of iron filings, we shall find that all these bodies are practically opaque to the electric rays. Moreover, we can show that not only is the above law true for solids, but it holds good for liquids as well. ”

“ I exposed the bare leading wires to the strong action of the radiator by putting them in close proximity to the source of radiation, and yet no response was observed in the galvanometer. This freedom from disturbance is not due to the opposite action on the two wires, for a single wire may be exposed to the radiation without any action on the receiver.
With small radiators the intensity of radiation is not very great. This is a positive advantage in many experiments. It sometimes becomes necessary to have greater intensity without the attendant trouble inseparable from too long waves. ”

“ Overhead was a magnificent Aurora Borealis extending high in bands of flickering color; a luminous phenomenon of all the colors of the rainbow, oscillating in electric waves. The gentle sighing of the wind, and an occasional dull, muffled sound from among the ice hummocks broke the silence. Near the trader were the dark figures of Kasba and David, in fact it was they who had given the alarm, and presently there was a slight crunching sound and Broom came striding up.
Dogs appeared as if by magic, and stood erect with ears pricked up expectantly, or darted forward with noses sniffing the air. ”

“ Double conductivity, its relation to double absorption, 73
Double refraction of electric ray, 95
Efficiency, photosynthetic of green leaves, 336
Electric radiation, electromotive variation induced by, 183
Electric radiation and mechanical stimulation, similarity of effects of, 204
Electric radiation and visible radiation, similarity of effects of, 187
Electric rays, complete polarisation of by, book, 99; chrysotile, 98; epidote, 9; jute cell, 17; nemalite, 9; serpentine, 16
Electric rays, polarisation, of by books, 99; crystals, 8, 95; gratings, 2; human hair, 96 ”

“ Theoretically all crystals, with the exception of those belonging to the Regular system, ought to polarise light. But this could not be verified in the case of crystals opaque to light. There is no such difficulty with electric rays, for all crystals are transparent to them. ”

“ It will be shown later that the two most important kinds of rays emitted by radio-active substances consist of electrified particles, spontaneously projected with great velocity. The easily absorbed rays, known as α rays, are positively electrified atoms of matter; the penetrating rays, known as β rays, carry a negative charge, and have been found to be identical with the cathode rays produced by the electric discharge in a vacuum tube. ”

“ The rays which it emits prior to redness are all invisible rays, which can warm the hand but can not excite vision. When the temperature of the wire is raised to whiteness these dark rays not only persist, but they are enormously augmented in intensity. They constitute about 95 per cent, of the total radiation from the white-hot platinum wire. They make up nearly 90 per cent, of the emission from a brilliant electric light. You can by no means have the light of the carbons without this invisible emission as an accompaniment. ”

“ The phenomena of elliptic polarisation, and perhaps also those of internal radiation,‍463 depend upon the refractive index, and thus, even when we cannot observe any refracted rays, we can indirectly learn how they would be refracted.
In many cases large quantities of electricity must be produced, which we cannot observe because it is instantly discharged. In the common electric machine the cylinder and rubber are made of non-conductors, so that we can separate and accumulate the electricity. ”

“ All men, able-bodied, I ordered to the roof of the city, there to wait for their arms and equipment which very soon would be furnished them. They were to divide themselves into two groups; older men whose power of giving the electric shock was waning ”

“ We may suppose that the process by which the retrograde rays are produced is somewhat as follows : neutral atoms or molecules acquire a negative charge when they are just in front of the cathode, they are then repelled from the cathode and driven through the dark space, acquiring under the electric field in the discharge tube a velocity of the same order as that acquired by the positively electrified particles of the positive rays during their approach to the cathode. ”

“ If radiation falls on an insulated metal plate connected with an electrometer, in an enclosure of the same metal, the positive electrification shown by the deflection of the electrometer is greater as the plate is further from the walls of the enclosure. The action stops when the metal has attained a certain electric density, constant for a given metal; so the potential of a plate is naturally higher as its capacity is less. It is thus established that radiation acts on the particles of gas in contact with a conductor ”

“ Fig. 9.— Zinc Rod discharging Negative Electricity in the very Ultra-violet Light of a Spectrum formed by a Quartz Train. The best discharging light is found far beyond the limits of the visible spectrum.
Return now to the Hertz vibrator, or Leyden jar with its coatings well separated, so that we can get into its electric as well as its magnetic field. Here is a great one giving waves 30 metres long, radiating while it lasts with an activity of 100 h.p., and making ten million complete electric vibrations per second. ”

“ An illustration of the development of this same form of electricity, on a large scale, is supplied by the familiar statical machine, which consists of a large circle of glass, so adjusted that it may be revolved rapidly against a suitable friction producer. With such a machine a powerful statical current is produced, capable of generating a spark that may be many inches or even several feet in length,—a veritable flash of lightning. It is with such a supply of electricity conducted through a vacuum tube that the cathode ray and the Roentgen ray are produced. ”

“ He not only produced combustion, fusion, and incandescence by invisible radiation, but he proved that in the case of the electric light the invisible rays are no less than eight times as powerful as the visible radiations. He obtained all the colours of the solar spectrum from a platinum foil raised to incandescence at the invisible focus; and this rendering of a refractory body incandescent by invisible rays he called calorescence. ”

“ If other electrons follow the first within a wire, their passage along the wire will be what is called an electric current.
When the electron is subjected to an acceleration, a transverse wave is produced, and an electromagnetic radiation is generated, of which the character may naturally change with the manner in which the speed varies. If the electron has a sufficiently rapid periodical movement, this wave is a light wave; while if the electron stops suddenly, a kind of pulsation is transmitted through the ether, and thus we obtain Röntgen rays. ”

“ We have, therefore, indubitable proof in all these experiments that we have something proceeding from the radiator which is capable of being reflected or refracted just like the rays of sound or ripples on the surface of water; and, moreover, we find that this electric radiation passes through some substances but not through others. There is, therefore, a strong presumption that we are here dealing with something which is similar in nature to light, although it cannot affect the eye. In order that we may complete the proof we must show that this radiation is susceptible of interference. ”

“ If we take into account the entire range of radiation there is hardly a substance which is not, in this sense, coloured. In the spectrum of radiation transmitted through glass, for example, two broad absorption-bands would be observed, one in the ultra-violet, and the other in the infra-red, the electric and the visible rays not being absorbed to any great extent. ”

“ It is, however, more satisfactory to study the effect of light in producing electromotive variation. Becquerel, Minchin, and others have shown that light produces electromotive variation in a photo-electric cell. Like electric radiation, the effect of light is not confined to any particular metal or groups of metals, but all metals exhibit an electromotive variation under its action. Two opposite effects are likewise shown; in some cases the potential is raised, in other cases the potential is lowered by the action of light. ”

“ Alan understood then that she was alone. They went inside the vehicle. It was dark in there. Alan could make out little, but after a moment his eyes grew accustomed to the darkness.
He noticed first that the thing was very solidly constructed. He expected to see some complicated mechanism, but there was little or nothing of the kind so far as he could make out in the darkness in this first hurried inspection.
Fastened to one wall was an apparatus which he judged was for the making of oxygen. He looked around for batteries, and for electric lights, but could see nothing of the kind. ”

“ The production of electricity by Motion is illustrated equally in the boy’s experiment with rubbed sealing-wax, in the common electrical machine, and in the apparatus for exciting electricity by the escape of steam. Wherever there is friction between heterogeneous bodies, electrical disturbance is one of the consequences. Magnetism may result from Motion either immediately, as through percussion on iron, or mediately as through electric currents previously generated by Motion. And similarly, Motion may create light ”

“ The light is not actually transmitted, but only its effects. Suppose a picture is laid off into small squares and there is a selenium cell corresponding to each square and for each selenium cell there is a wire that runs to a distant station in which circuit there is a battery. At the distant station there are little shutters, one for each wire, that are controlled by the electric current and so adjusted that when the cell at the transmitting-end is in the dark the shutter will be closed. ”

“ To this ether are ascribed the principal phenomena of attraction and repulsion, whereas the light, the smell, and other sensible qualities of the electric fluid are referred to the grosser particles of bodies, driven from them by the forcible action of this ether. Many phenomena in electricity are also attempted to be explained by means of a subtile medium, at the surface of all bodies, which is the cause of the refraction and reflection of the rays of light, and also resist the entrance and exit of this ether. ”

“ Once we assume the existence of this physical though imponderable, that is, weightless substance, we may regard it as instrumental not only in the transmission of gravitational forces, but also of electric and magnetic forces and as the carrier of light and heat rays. There is, indeed, very strong experimental evidence that light, electricity, magnetism and all other manifestations of energy are propagated by ether vibrations. ”

“ I mean the true ethereal waves emitted by the electric oscillation going on in the neighborhood of this recoiling dielectric. You pull aside the prong of a tuning fork and let it go; vibration follows and sound is produced. You charge a Leyden jar and let it discharge; vibration follows and light is excited.
It is light just as good as any other light. It travels at the same pace, it is reflected and refracted according to the same laws; every experiment known to optics can be performed with this ethereal radiation electrically produced, and yet you cannot see it. ”

“ The Röntgen rays are certain invisible rays resembling, in many respects, rays of light, which are set free when a high-pressure electric current is discharged through a vacuum tube. A vacuum tube is a glass tube from which all the air, down to one-millionth of an atmosphere, has been exhausted after the insertion of a platinum wire in either end of the tube for connection with the two poles of a battery or induction coil. ”

“ It is thus seen that the curve of electromotive variation due to radiation is similar to that obtained by the conductivity variation method.
It has already been shown that when the range of electric elasticity of the substance is not narrow, or when the strain is not too great, there is a recovery. That on subjecting the substance to the continued action of radiation there is a limiting effect; that too long continued action tends to produce an electric reversal; that too feeble an intensity may also produce a reversed effect. ”

“ For though there is a difficulty in supposing ordinary physical vibrations or radiations to reach effectively from one person to another (say a thousand miles away) on account of the law of space itself, which makes such radiations diminish in intensity as the square of the distance increases, yet in the case of electrical radiations it seems possible to suppose two people related to each other as positive and negative poles—in which case the radiations of electric charges would pass along lines connecting the two, and with comparatively little loss of intensity. ”