AB scientific discoveries in increasing numbers are passing from the sphere of the laboratory into our everyday life, becoming after some little time what we are pleased to call necessities, the public are frequently called upon to decide for or against the adoption of some novel development of the utilisation of the forces of nature; as such schemes invariably involve a financial problem, the engineering profession is required to lay the case clearly before the corporate bodies or others who have the final decision in their hands. It is consequently of some importance that non-professional people should know and understand, not the intricate details, but what the real issue at stake is. A fierce battle is just now raging between electricity on one side and steam and gas on the other; the former assures us that she will in a clean and efficient way, light up our houses, cook our food, and transport us with the swiftness of lightning to any place we like, and all for a mere song. Don't listen to the upstart and don't throw over your old friends, say gas and steam; didn't we rescue you from the smoking lamp and the jolting cart, and have you no gratitude? But before we have even time to answer, the said upstart retorts that they are now claiming what they formerly maintained were not the just due of the smoking lamp and jolting cart; so we decide not to determine the question on sentimental grounds but from practical experiments and financial results. Whether we will have incandescent gas light or electric light, a question now prominently before this, community, depends on many factors and we propose to give our readers a resume of what we saw in Europe, not with the eyes and understanding of one who would discuss the lighting power of gas expressed in 02 H2, C2 H4, ete., and electricity as measured in volts and amperes; but according to the impressions it made upon us as ordinary persons whose interest in the matter would be confined to using and paying for it, Most people have probably heard that the amount of light yielded by gas depends eminently on the temperature of the fame. In our fireplaces we may have a very largo flame (which of course is nothing but a gas flame) but it gives little light owing to a low temperature, which again is due to an excess of cold air. It is to a great extent the small particles of carbon which are brought to incandescence in a gas flame that give off light; and as an iron rod heated to whiteness gives off more light than one heated to a dull red only, ao it is with the particles of carbon. The efficiency of the incandescent gas-burner, with which we are now making acquaintance in Shanghai, does not depend on a new principle, but simply on the successful manufacture of a thin gauze, called the mantle, enveloping the flame, and prepared in such a manner that it does not burn away in the fierce heat which it causes, and through which the particles of carbon are brought to a brilliant white heat. When it is claimed that with less consumption this new burner gives several times as much light, many people will naturally be somewhat sceptical; but it is absolutely correct; and against this great advantage, there is only the high cost of the mantle, and the fact that it has to be renewed occasionally, a circumstance that one does not see mentioned very often. We noticed several public places in Paris lighted by this gas burner, and the effect was extremely brilliant the light seemed to approach the effect of moonlight more closely than the electric are light; if used with a white chimney and indoors the incandescent gas light has often slight greenish tint which is somewhat ghostly and not at all becoming to the complexion but with a pink chimney, the light seems almost perfect, except that for indoor installations there is of course
Text read from the printed page and cleaned; old type leaves the occasional error.