The field on which I propose to enter can hardly be said to be already occupied. Nowhere that I know of is the subject of gas-burners fully treated of in a manner available for the general reader. With the exception of the admirable chapter contributed by Mr. R. H. Patterson to "King's Treatise on Coal Gas," I am not aware that the subject has been dealt with to any complete extent by recent writers. But, admirable as is that contribution to the literature of the subject, being written for technical readers, it is neither so popular in style nor so elementary in character as to fulfil the purpose which I have in view in writing the present series of articles. Briefly stated, my sole purpose is to make the subject of the combustion of gas for the production of light intelligible to the simplest; and to present an interesting account of the progress of invention in the perfection of gas-burners. While passing lightly over many modifications of apparatus which have been of but limited or temporary service, I shall not scruple to dwell at length upon such burners as have done much to further the extension of gas lighting, or whose construction exhibits a considerable advance upon previous attainments. And while it will be my endeavour to clothe my remarks in such language as shall be "understanded of the people," in speaking of the theory of combustion I hope to be sufficiently explicit to enable my readers to form a clear conception of the scientific principles underlying the phenomena of which I treat. [Sidenote: Progress of gas lighting.]