Page:Lippincotts Monthly Magazine-46.djvu/538

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ELECTRIC LIGHTING.

The old hotel-tyrant of Florida is on the decline. Let him seek a place of repentance, space will be given him; but and if he will not repent and do works meet for repentance, he shall read his Tekel, Tekel, on his own deserted walls. The tourist will see to that.

Rose Elizabeth Cleveland.


ELECTRIC LIGHTING.

TO bring to the understanding of the general reader how the electric light is produced is no easy matter. In order that the untrained mind may realize natural laws and phenomena which are either unknown or unfamiliar to it, the necessity arises to introduce comparisons between them and the phenomena which are within its knowledge. This is not a strictly scientific method of proceeding, and, when employed in this article, any comparisons given must be limited only to the statement made: there must be no further deduction, whether such deduction be right or wrong.

Practical electricity is the application of a certain known force to practical ends, such as telegraphy, telephony, lighting, motive power, welding, chemical operations, medicine, and an infinite number of other purposes. Lighting and motive power only will be treated here. This subject divides itself into three parts: (1) the production of the force,—i.e., electrical energy; (2) the means of conveying it to the point or points where it is to be used; and (3) the apparatus for giving the desired results.

Although there is a variety of ways of producing electricity, from the rubbing of a piece of sealing-wax on the coat-sleeve to the vast engines employed at large central lighting-stations, yet here we will consider only such methods of producing the force as are in practical use on a moderate scale. The current for electric lighting may be obtained either from chemical batteries or from machines termed dynamos. The dynamo is an apparatus a portion of which has to be revolved in order to produce a current, and consequently requires some motive power, which is supplied from a steam-engine or some other source. It must be remembered that a steam-engine derives its power from the fuel in the boiler-furnace, or from gas, petroleum, or some other material, being consumed,—to use a common phrase,—for in reality it is simply the material changing its chemical state, no actual consumption taking place at all. It will thus be observed that the power obtained from all engines is derived, in the first instance, by a chemical process, and is, therefore, comparable with a complex chemical battery. It might be thought that, the current is produced by water-power, chemical action is no longer the source of current-production; but this is not so, for the water which produces the power has been raised from low levels in the form of vapor to high levels, where this vapor is deposited in the form of rain, by the action of the sun’s heat,—which is produced by chemical action. Therefore it may