A further justification--if such, indeed, were needed--for the appearance of this treatise might be found in the remarkable impetus which has been given, within recent years, to the perfection of the details of gas manufacture and the improvement of gas-burners. Of course, I refer to the beneficial consequences to the gas industry which have followed the brief, if conspicuous, career of electricity as an illuminating agent. That the interest in improved illumination which has been aroused by the short-lived popularity of the electric light, and the extravagant claims put forward on its behalf, have stimulated to the development of the resources of gas lighting, is sufficiently obvious to the most superficial observer. And not only has the manufacturer of gas been benefited, but the public have reaped no inconsiderable advantage. At the present day, gas is sold at a far cheaper rate, as well as of a higher quality, than at any former period. Nor is the advent of cheap gas the only direction in which the public have gained. Although not so patent to the majority, the improvements that have been effected in the methods of burning gas, so as to obtain the fullest advantage from its use, are calculated to confer benefits equally real, and not less valuable. It is hardly too much to say that the last few years have witnessed a greater advance in the apparatus employed in the combustion of gas than had been effected during the whole previous history of gas lighting. This being so, it may not be unacceptable if I attempt to pass in review some of the various burners that have been invented and used for obtaining light from coal gas; showing the successive improvements that are exhibited in their construction, and the extent to which they apply the principles of combustion. It may be that what I have to relate will awaken some minds to the consciousness that gas lighting has not altogether retired into obscurity on the advent of electricity--nay, that it has even assumed a bolder front; and, with increased resources and accession of strength, is prepared firmly to maintain its position as at once the most convenient, economical, and reliable of artificial illuminants. CHAPTER II. FLAT-FLAME BURNERS. THE FIRST GAS-BURNER.