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factor in our civilization, is becoming daily of more importance.
Millions of capital are being invested in its production, and it is being introduced throughout the world as rapidly as human activity, supplemented by all the agencies of an advanced civilization, can accomplish this end.
It is to meet the want among the intelligent laity, that is now—and will be later on more keenly—felt, for a general knowledge of this subject, superficial perhaps, but yet connected and logically arranged, that the publishers have decided to re-issue this number of their Science Series, with the matter contained therein, thoroughly revised and brought down to date; and trust that the same generous appreciation which attended their first effort, will justify them in this attempt to give to the public a popular exposition of the art of electric lighting by incandescence.
While a system of electric lighting, includes a large number of devices, the greater portion of these are simply
