Electric lamp

“ The glow-lamp in process of manufacture before you is now being unsealed from the pump; it is now exhausted, and we will pass a current through it so as to raise it to incandescence. The current is now on, and you see the lamp burns with full brilliancy. The next experiment is rather a cruel one, because it is willful destruction. I will not destroy the lamp that has just been made before us, for I will keep it as a memento of this evening. I want to show the safety of the electric lamp. Many people imagine that there is a great deal of danger about it. ”

“ 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. ”

“ The electric light in the form of the well-known powerful and dazzling arc-light is the favourite illuminant for lighting harbours, 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. ”

“ The lamps referred to here are those having a pear-shaped glass bulb, and which are known as incandescent lamps. The kind we see in the streets, giving a very powerful light, are called arc-lights. With this class of lights, however, we will have nothing to do here. The object of this article is to give plain directions for the construction of a battery to light a small electric lamp. Some boys may think that because electricity is something mysterious it must be very difficult to produce ”

“ Lamps not to be run too bright. For the sake of economy, it is well not to run the lamps too bright. Without giving the lamps the maximum current a very good light can be obtained, and they will last all the longer. I need hardly say that there is a medium in this as in everything else, and it does not look well when a candle is placed alongside of an electric lamp to enable a person to read or write in comfort.
All this time the dynamo is running, and we must feel the bearings occasionally to see if they [39] are keeping cool. No trouble with dynamo if oiling is attended to. ”

“ 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 must be remembered that electric lighting is comparatively a new science, and not yet fully understood. There is very little doubt that, by practice, it will before long approach more nearly to perfection, and sooner or later entirely supersede gas, the arc form of lamp being employed for the illumination of streets and large areas, while the incandescent pattern meets domestic requirements.—Good Words. ”

“ It is quite probable that the electric lamp of the next century will cost far less than any now in use. We are yet in the infancy of electrical invention, and it may be wise for communities to suffer a little longer the evils of darkness in order to obtain the best appliances for public lighting. ”

“ It is securely fastened to the table, which in its turn is fastened to the floor, and the light is supplied by a small incandescent lamp within the chimney, but concealed by the shade. The visitor never imagines that it is an electric lamp, and naturally thinks that it would be impossible for a kerosene lamp to be inverted without disaster, so that this adds to the deception materially. ”

“ While the copper and platinum wires readily conduct the current, the carbon filament offers a great deal of resistance to its passage, and for this reason becomes very hot, in fact is raised to white heat or incandescence, which gives its name to the lamp. ”

“ Although electricity, like the air around us, seems very impalpable, appealing to so few of the senses, it is yet capable of being measured, for in order to run the lamps economically, we must give each of them only its due measure of the electric current passing over the wires. ”

“ The invention and development of the drawn-wire lamp, made by various firms and sold under trade names such as "Osram," "Mazda," and "Z," have made a great saving in the annual bill for electric light, and at the same time have raised the standard of illumination. With the carbon filament, a 32 c.p. lamp would burn for seven and a half hours with the expenditure of one unit of electricity. Now the same light can be obtained for twenty-five hours at the same cost with the metal filament lamp. ”

“ The various devices once placed are likely to last under ordinary usage as long as the householder will probably live to enjoy them; the only exception to this general statement being the lamp itself which, with the proper current for which it is constructed, is guaranteed to last one thousand hours. ”

“ A small electric lamp is set in the end of a hollow tube of tin, and about the lamp is a reflector. Dry electrical batteries are put in the tin tube, and by means of a push button the circuit is closed, illuminating the lamp, which gives a brilliant glow. Tom had a special kind of lamp. with tungsten filaments, which gave a very powerful light, and with batteries designed to last along time. A clip on the spring controlling the push button made it so that the lamp could be made to give a steady glow. Thus they were well prepared for exploring the tunnel. ”

“ 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. ”

“ Sometimes two or more lamps are placed in groups between the parallel leads; these are then in series with regard to one another, and can only be turned on or off two or more at a time, in other words, one group at a time. If lamps suitable, each one turns on and off separately. If our dynamo is producing a current of 100 volts E.M.F. when working at its proper speed, and our lamps are 100-volt lamps, we shall be able to turn each lamp [27] on or off separately; but if we want to put in 50-volt lamps, we must place two together, and we shall then have to turn them on or off two at a time. ”

“ For indoor, public room or factory lighting, inverted arc lamps are sometimes employed. In this case the positive carbon is the lower one, and the lamp is carried in an inverted metallic reflector shield, so that the light is chiefly thrown up on the ceiling, whence it is diffused all round. The alternating-current arc is not only less efficient in mean spherical candle-power per watt of electric power absorbed, but its distribution of light is disadvantageous for street purposes. ”

“ In practical electric lighting, the number of lamps receiving their current from a common central station^ often runs up into thousands; and, as it is neither practicable nor desirable, to run these lamps all from one generator, a number of generators have to be combined together to furnish the necessary current, each generator having a capacity of a given number of lamps. ”

“ The amendment, in 1888, of the Electric Lighting Act of 1882, before long caused a huge development of public electric lighting in Great Britain. By the end of the 19th century every large city in Europe and in North and South America was provided with a public electric supply for the purposes of electric lighting. The various improvements in electric illuminants, such as the Nernst oxide lamp, the tantalum and osmium incandescent lamps, and improved forms of arc lamp, enclosed, inverted and flame arcs, are described under Lighting: Electric. ”

“ In order, however, that the lamps farthest removed from the generator shall have as much current as those nearest to it, the main conductor must of necessity be so large as to present practically no resistance to the passage of the current; for this reason the two-wire system cannot well be used, under conditions requiring the current to be led a long distance to the point where the lights are to be used, as the cost of the large copper conducting mains becomes so great as to seriously interfere with the economical introduction of the system upon a commercial basis. ”

“ To make this clearer, we will say that two dynamos are started late in the afternoon a little before the time when lighting generally commences. If no lights are turned on there will be no current generated, because we shall have what is termed an open circuit; that is, there will be no connection between the outgoing and incoming, or what is known as the positive and negative wires, as there is when lamps are in circuit. ”

“ The average candlepower of standard lighting lamps has increased from 16, which prevailed during the period prior to 1905, to over 60. The average wattage has not varied much during the past twenty-odd years, the average lamp now consuming about 55 watts. This indicates that the public is utilizing the improvement in lamp efficiency by increased illumination. The present most popular lamp is the 40-watt size which represents 20 per cent of the total demand. Second in demand is the 25-watt at 18 per cent and third, the 50-watt at 15 per cent of the total in numbers. ”

“ In some lamp-fittings the ends of the leads are held in a spring grip in the base of the bracket, and it may happen that they have slipped out, and so broken the circuit, and extinguished the light. In the Swan lamps, and others of a similar pattern, one of the little platinum loops in the base of the lamps sometimes gets broken off; the lamp is then of no further use. Recapitulation. To recapitulate, if a lamp goes out, the first thing is to see if the [41] filament is broken, next if it makes good contact. If it does not then light up, see if there is any current getting to it ”

“ Voltaic Arc by Sir Humphrey Davy—The Jablochkoff Candle—Patents of Brush, Weston and Others—Search Lights—Grove’s First Incandescent Lamp—Starr-King Lamp—Moses Farmer Lights First Dwelling with Electric Lamps—Sawyer-Man Lamp—Edison’s Incandescent Lamp—Edison’s Three-Wire System of Circuits—Statistics.
The popular idea of the electric light is, that it is a very recent invention, since even the younger generation remembers when there was no such thing in general use. ”

“ The excess of current, as lights are turned off, being taken care of by introducing the resistance of the regulators up to the proper point, and then operating upon the fields of the dynamos, until the current necessary for the lamps in circuit falls to a point where it is expedient to cut out a pair of dynamos. ”

“ The Thomson-Rice single lamp has the same gear with the exception of having only carbon holder C, H, lever ON, and spring clutch and spring P being absent. The single lamp will burn eight hours and the double lamp fourteen hours continuous running. ”

“ It was evolved from the early observed fact that a conductor is heated when traversed by an electric current, and that if it has a high resistance and a high melting-point it may be rendered incandescent, and therefore become a source of light. Naturally every inventor turned his attention to the employment of wires of refractory metals, such as platinum or alloys of platinum-iridium, &c., for the purpose of making an incandescent lamp. ”

“ That the operations just described should be intelligently and carefully performed, is of the greatest importance, as each lamp when burning represents a given amount of coal being consumed at the station; and as the light is sold at a predetermined and stated price, just as gas is, it is necessary, in order to have the electric light company's books balance in favor of the proper parties, that no coal should be burned unless the light is in actual use. ”

“ 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. ”

“ The electric glow-lamp, and the most popular and economical modern enclosed electric arc-lamp, sterilise only the much smaller volume of air which is brought into direct contact with their glass bulbs. ”

“ If the favor in which the electric light is held, and the great extent of its use, rested solely on the question of cheapness of production, such question would give rise to interesting debate. And, indeed, the debate would continue, if the question were the superior fitness of electric lighting for lighthouses and like service, where extreme brilliancy does not seem to penetrate a thick atmosphere as effectively as the more subdued glow of the oil lamp. ”