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Coming of Electric Lighting 233 be charged afterwards with nitrogen. Not only was the light emitted from the glowing filament in this instance found to be the nearest approach to natural sunlight in colour which had yet been accomplished, but, more remarkable still, the consumption of current for a given light equal to so many candles was still further reduced. The appearance of the nitrogen lamp, as it is colloquially termed, created almost as pronounced a sensation as that of the first Swan carbon filament type. Curiously enough, being possible only in high candle-powers, which are far too excessive for ordinary house lighting, it was hailed as being a powerful rival to the arc-lamp. In fact, it was described as an application of the incandescent filament lamp to the field of arc-lighting, with all the advantages of the two systems and none of the latter’s disabilities, such as the renewal of the carbons at frequent intervals. As a result the nitrogen lamp speedily made its way for the illumination of public spaces, streets, and buildings where powerful lights are required. With this lamp the consumption of electricity per candle- power is considerably less than one-half of that of the best type of metallic filament lamp. Up to the present, however, small or low-powered units—from eight to thirty-two candle-power—suitable for ordinary house lighting have not been found possible. But our electrical chemists and scientists are busy in the laboratories, and it is quite possible that the nitrogen lamp will be produced in such a form as to facilitate its utilisation for lighting our homes. Some years ago another and totally different type of glowing lamp made its appearance. This differs