Electric light

“ A SMALL ELECTRIC-LIGHT OUTFIT. HOW TO MAKE THE BATTERY AND HOW TO SET IT UP. BY THOMAS R. TALTAVALL.
All young readers of Harper's Round Table are probably familiar with the appearance of the electric light—that wonderful little glass bulb that we see in stores, hotels, theatres, etc.—and no doubt many have wondered what causes the hairlike loop inside the bulb to become so brilliantly luminous. Electricity does it; but no one knows what electricity is, not even the most advanced scientific thinker of the day. ”

“ Now that the electric light has been made available for domestic purposes, and the very simple lamp (consisting of an exhausted glass globe, two platinum wires, and a piece of charred paper) can be obtained, people will no doubt soon largely adopt electric lighting in their houses. The light has found a success at the theatre, in the streets, and in the train; there is no reason why it should not be adopted generally, being more economical and more healthy than gas.
Fig. ”

“ It is true that in an electric-lighting system there is also a fall or loss of electrical pressure which occurs in overcoming the much greater resistance of the filament in an incandescent lamp. In this case there is also a translation of the energy, but here it accomplishes a USEFUL purpose, as the energy is converted into the form of light through the incandescence of the filament. ”

“ The lighting effect is produced by the passage of the electric spark through the small gap which separates the carbon points, in which interval extremely minute but solid particles of carbon, given off by the points, are heated up to incandescence in the path of the spark, and thus give rise to the intensely luminous focus known as ‘the electric light.’ The brilliancy of the light of course depends upon the quantity of electricity employed. ”

“ In the distant future, electricity will be used for electric lighting only as subordinate to other uses to which it may be applied such as heating houses, taking place of stoves for cooking, being used as a substitute for the steam engine. In fact the motor is rapidly becoming of as much practical use as the electric light. ”

“ On passenger steamers, side one blaze of light, and side lights barely visible. but many who have seen a large passenger steamer go past will have noticed how her side was—one, [43] two, or three rows of dazzling bright lights, and will have looked almost in vain for the green or red light dimly visible in the midst of all the bright ones. If bright electric lights, therefore, are shining through the ports, we must have our side lights at least as bright, so as to give them a chance of being seen. If electric lamps are used as side lights, the dynamo must be kept running all night. ”

“ The electric light in the form of the well-known powerful and dazzling arc-light is the favorite illuminant for lighting harbors, railway stations, docks, public works, and other large spaces. But it is to the incandescent lamp that one must look par excellence for the “light of the future.” It has been satisfactorily established that lighting by incandescence is as cheap as lighting by gas, provided that it be carried out on an extensive scale. ”

“ In the case of the electric light, the heating of a conductor to incandescence in a highly rarefied atmosphere was suggested as a scheme of illumination long before its actual accomplishment, and in fact before the production of a suitable generator for delivering electric current in a satisfactory and economical manner. ”

“ The electric matter in passing through non-conducting substances always emits light. This light I have been sometimes inclined to suspect might have been supplied from the substance through which it passes. But I find that after the electric spark has diminished a quantity of air as much as it possibly can, so that it has no more visible effect upon it, the electric light in that air is not at all lessened. It is probable, therefore, that electric light comes from the electric matter itself ”

“ During the intervening thirty years I have abstained from further meddling with the electric light, because all that I had seen then, and have heard of since, has convinced me that—although as a scientific achievement the electric light is a splendid success—its practical application to all purposes where cost is a matter of serious consideration is hopeless, and must of necessity continue to be so. ”

“ In addition to the large number of advantages possessed by the electric light over all other forms of artificial illumination, it may be said to be far in advance of all others in the readiness with which it may be adapted to all forms of decoration. ”

“ The electric light was found to suffer to a much larger extent than either oil or gas light per unit of power by atmospheric absorption, but the infinitely greater total intensity of the beam obtainable by its use, both by reason of the high luminous intensity of the electric arc and its focal compactness, more than outweighed the higher percentage of loss in fog. ”

“ Portable Electric Light. — An ingenious little electric-light apparatus (says the Mining Journal) has been invented by Mr. Facio, of Paris, and is applicable to watches, walking-sticks, and such like. ”

“ Where the electric light came in as a great and lasting boon was in the lighting of the interior of the air chambers and air shafts of the large pneumatic caissons while in the process of sinking. The absence of all smoke or filth due to oil lamps of whatever description, the facility with which they could be moved, changed, put up or taken down, was of incalculable advantage in places where breathing even the purest air was a task of some discomfort and difficulty, and here, therefore, the electric light reigned supreme. ”

“ Lighting, Electric (Vol. 16, p. 659) deals with arc, incandescent and vapour lamps, and with wiring. The section on household work gives excellent practical information about the best arrangements of lights. A special class of electric light supplies is discussed in Lighthouse (Vol. 16, p. 627) , by W. T. Douglass, who erected the new Eddystone and the Bishop’s Rock lights, and by N. G. Gedye, another practical expert.
The appliances used to convert current back again into the mechanical energy from which it had been derived are described in the article Motors, Electric (Vol. 18, p. 910) . ”

“ Division of the Light.—Hitherto a separate pile, or a separate machine, has been necessary for the production of each electric light, and it has been found impossible to place two lamps in one circuit. This is readily understood when we consider the mechanism of the regulating apparatus. In electric lamps the approximation and the separating of tlie carbons are controlled by an electro-magnet, which itself follows the variations of resistance in the circuit produced by changes in the length of the voltaic arc. ”

“ If one lamp went out through the filament giving way, it would not affect the others, so that there would still be a light in the lantern. If, through some breakdown of the engine or dynamo, the electric current were no longer to be had, then it [42] Mast-head light. would only be necessary to withdraw the stand of lamps, and put in the ordinary regulation oil-lamp. The mast-head lamp could also be fitted with the electric light, as indeed has already been done. Arc light should never be used. ”

“ No time will be lost in putting this announcement to the test, not only of scientific but also of practical verification, and the probability is that all electric lighting stations in the twentieth century will contain not only dynamos of one type for the supply of light, but also direct current generators for transmitting power in all directions over the same cables. ”

“ They remain lighted, each one independent of the other. The reader will quite readily understand, therefore, that a multiple-arc system is the only one practically commercial where electric light is to be used in small units like those of gas or oil. ”

“ It has been stated that modern theory recognizes two classes of electricity, the Static and the Dynamic. The difference is, however, solely noticeable in operation. Of the dynamic class there can be no more common and striking example than the now almost universal electric light. Yet, with a sufficient expenditure of chemicals and electrodes, and a sufficient number of cells, electric lighting, either arc or incandescent, can be as effectively accomplished as with the current evolved by a powerful dynamo. ”

“ Thus, regardless of the intensity, the ordinary electric light when used alone has been demonstrated to be a poor light source. Its maximum energy occurs in the infrared region, below the limit of visibility, while that of sunlight falls in the green-blue region. ”

“ The lighthouse electric light is also a noble application of the great power of a single electric light on the arc principle. The most powerful electric light in the world is situated near here on the coast, between the Tyne and the Wear. ”

“ This is called the multiple circuit, and it is obvious that the entire amperage produced by the dynamo will not be required to pass through each lamp, but, on the other hand, each lamp takes only enough necessary to render the filament incandescent.
This invention at once solved the problem of the incandescent system and was called the subdivision of the electric light. By this means the cost was materially reduced, and the wiring up and installation of lights materially simplified. ”

“ Electricity cannot manifest as light in the usual electric lights used in our houses, as heat in the electric culinary appliances or stoves, or even as power in the motors which run our trams and trains, unless it be given the requisite apparatus to bring about the manifestation required. ”

“ Some lamps suitable for alternating current. Some lamps have been constructed for use with an alternating current, but with the majority a continuous current is used. [20] While an arc light is burning the carbons waste away, the upper one more rapidly than the lower, and the mechanism has to approach them constantly to make up for this waste.
When carbons are consumed light goes out. When the carbons are consumed as far as convenient, an automatic arrangement cuts off the current, and the light goes out; or it diverts the current to another set of carbons, which at once light up. ”

“ With the introduction of the electric light into the streets of our towns and cities, we meet a new danger from broken wires, charged with electricity, hanging in the air. In New York City, last month, an electric light pole was broken and the wires fell to the ground, when a runaway horse had a strange experience. ”

“ THE employment of the electric light for general purposes of illumination has not, hitherto, been successful. The difficulty of maintaining it constant, and the expense attending its use, have prevented its employment. In the old method of producing the light by a great number of cells, the chief difficulties arose in keeping the strength of the current constant, and in regulating the distance of the carbon-points between which the light was produced. ”

“ Instead of a platinum wire, a fine thread of carbon is brought to a very high temperature by the passage through it of the electrical current, in which condition it gives out light. All that you have to do to light up is to connect your lamp with the battery. The reign of the match, as you see, so far as incandescent electric lamps are concerned, is a thing of the past. We need no match to fire it. ”

“ Gas light is more difficult to manage than electricity, for there is always the cumbersome tube and the necessity for adding mechanical accessories before a good clear light is secured. Gas lamps are hideous, for some obscure reason, whereas there are hundreds of simple and excellent wall fixtures, drop lights and reading lamps to be bought already equipped for electricity. The electric wire is such an unobtrusive thing that it can be carried through a small hole in any good vase, or jar, and with a suitable shade you have an attractive and serviceable reading light. ”

“ In the course of the following year the apparatus for lighting, by means of carbon candles was introduced into many of the principal factories of France and other leading countries of Europe. It may prove of interest in this connection to sketch briefly the principal features of the electric light system, and to trace the development of that system in our own and other countries.
Lighting by electricity is accomplished in several ways. ”

“ The second form of illumination is what is known as the 'incandescent system,' and consists generally in the passage of a current of electricity through a continuous strip or piece of refractory material, which is a conductor of electricity, but a poor conductor; in other words, a conductor offering a considerable resistance to the flow of the current through it. It was discovered early in this century that various substances might be heated to a white heat by passing a sufficiently strong current of electricity through them. ”

“ We have, therefore, here, in a building 75 × 100 feet, apparatus and all departments complete for the generation and supply of current and power for a capacity of 40,000 lights, or the equivalent in light and power, and so arranged as to secure, as far as can be foreseen, continuous working of the plant and entire reliability in the furnishing of its current. ”

“ The positive electrode is a piece of copper sheathed in iron to prevent oxidization of the copper. The arc flame gives a brilliant white light, and, similar to the mercury arc, is inherently limited to direct current. It burns in the open air at about 75 volts. The lamp is made for 4-ampere direct current series circuits and consumes about 310 watts and has an efficiency of about 111⁄2 lumens per watt. ”