Electrical Telegraphy in the United Kingdom > 자유게시판

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This apparatus was to be positioned in the path of a parallel beam of gentle, and the undulatory beam rising from the apparatus could possibly be obtained at some distant place upon a lens, or different apparatus, via which it could be condensed upon a sensitive piece of selenium placed in an area circuit with a telephone and galvanic battery. The beam is acquired at a distant station upon a parabolic reflector, in the main focus of which is positioned a sensitive selenium-cell, connected in a neighborhood circuit with a battery and phone. Another method of affecting a beam of gentle is to cross it through a lens of Tariable focus. I obtained some selenium for the aim of producing the apparatus shown; however discovered that its resistance was almost infinitely larger than that of any phone that had been constructed, and I used to be unable to acquire any audible results by the action of mild. The loudest effects obtained from gentle are produced by rapidly interrupting the beam by the perforated disk. Upon additional consideration it appeared to me that all of the audible effects obtained from sorts of electricity may be produced by variations of light performing upon selenium.

We have devised about fifty types of apparatus for various a beam of mild in the style required, but only some typical varieties want be shown. Just a few days afterward my concepts upon this topic obtained a fresh impetus by the announcement made by Mr. Willoughby Smith before the Society of Telegraph Engineers that he had heard the motion of a ray of gentle falling upon a bar of crystalline selenium, by listening to a phone in circuit with it. I used to be a lot struck by the idea of producing sound by the motion of gentle in this way. We've got additionally found that brass, though chemically acted upon by selenium, types an excellent and handy material; certainly, we are inclined to imagine that the chemical action between the brass and selenium has contributed to the low resistance of our cells by forming an intimate bond of union between the selenium and brass. The fundamental thought, on which rests the potential of producing speech by the action of gentle, is the conception of what may be termed an undulatory beam of mild in contradistinction to a merely intermittent one. By such experiments we've discovered that articulate speech could be reproduced by the oxyhydrogen light, and even by the sunshine of a kerosene-lamp.

The beam of polarized mild, as an alternative of being handed by means of a liquid, could also be reflected from the polished pole of an electromagnet. When a solution of alum, or bisulphide of carbon, is employed, the loudness of the sound produced by the intermittent beam is very barely diminished; however a solution of iodine in bisulphide of carbon cuts off most, however not all, of the audible effect. No impact is produced in the course of the passage of a steady and steady current. It is only for the time being of change from a stronger to a weaker state, or vice versa, that any audible effect is produced, and the amount of impact is exactly proportional to the quantity of variation in the present. It was, subsequently, evident that the telephone could only respond to the effect produced in selenium in the intervening time of change from light to darkness, or vice versa; and that it could be advisable to intermit the light with great rapidity, in order to supply a succession of changes in the conductivity of the selenium, corresponding in frequency to musical vibrations inside the bounds of the sense of hearing. The curve that may graphically signify the changes of light would be comparable in shape to that representing the movement of the air.

Since the facility stream by way of an HVDC link may be controlled independently of the section angle between source and load, it could actually stabilize a community in opposition to disturbances attributable to fast adjustments in energy. In arranging the apparatus for the aim of reproducing sound at a distance, any powerful supply of light could also be used, but now we have experimented chiefly with sunlight. We have found that, on eradicating the supply of heat instantly on the appearance of the cloudiness, distinct and separate crystals might be observed under the microscope, which seem like leaden snow-flakes on a floor of ruby crimson. A cloudiness step by step extends over it, considerably just like the film of moisture produced by respiratory upon a mirror. We have observed that melted selenium behaves to the opposite substances as water to a greasy surface, and we are inclined to assume that, when selenium is used in connection with metals not chemically acted upon by it, the points of contact between selenium and the metallic provide a considerable amount of resistance to the passage of a galvanic current.