The premier position among gas-burners undoubtedly belongs to the Argand; and it is from no unwillingness to recognize its claims, much less from ignorance of its merits, that I have left the consideration of this burner until now. It occupies this honourable position as much by virtue of the importance it has acquired through being accepted by Parliament as the test burner, and the peculiar relation in which it consequently stands to other burners, as for any marked superiority in operation. For while, in general, the Argand gives superior results to other burners, this is not always the case. There are circumstances and conditions to which the Argand is quite inapplicable, and where a simpler and less pretentious burner will give excellent results. Indeed, some of the simple flat-flame burners which we have had under notice have now been brought to such a stage of perfection, that, when intelligently used, they not unsuccessfully rival the Argand. But it has been in the direction of demonstrating the illuminating power which it was possible to obtain from gas, and stimulating to the attainment, by other and simpler burners, of the same level of excellence, that the influence of the Argand has been most beneficial. For, by reason of its peculiar construction, and more especially its mode of obtaining the air necessary for combustion, the Argand lends itself, more readily than any other burner, to the work of investigating and experimenting upon the conditions necessary for economical combustion, and the development of the highest illuminating power from the gas consumed. In this burner, the air supply to the flame is under complete control; and thus one of the chief elements of uncertainty and difficulty which are experienced in dealing with other burners is eliminated. The delivery of gas to different parts of the flame is also more susceptible of variation; and the results of such variation more fully exposed to observation. The consequence has been that the most remarkable advances in developing improved illuminating power from coal gas have been made with this burner. But after the possibility of obtaining an improved duty from the gas has been demonstrated by means of the Argand, and the conditions necessary for its attainment determined, equally good results have been achieved by other burners. [Illustration: PLAN OF GLASS-HOLDER AND BURNER TOP. SECTION OF BURNER. FIG. 13.--ARGAND BURNER.]