In a recently designed modification of the burner (which is shown in the accompanying illustration) M. Clamond dispenses with an artificial supply of air under pressure, and endeavours to obtain similar results by other and simpler means. To this end the position of the magnesia "wick" is reversed (it being placed at the top of the apparatus); the current of gas is allowed to draw in upon itself a quantity of air by a precisely similar arrangement to that adopted in the Bunsen burner; while an additional supply of air is drawn upon the flame by the accelerated draught produced by the aid of a glass chimney. As in the more complicated and complete burner, the air supply is heated by means of auxiliary burners in the interior of the apparatus. It has been stated, on the authority of M. Clamond, that this modified burner develops, from the gas consumed, a duty of about 6 candles per cubic foot; being equal to the results yielded by the more complicated apparatus. Should this be borne out in practice, M. Clamond will have achieved a noteworthy success. It is, however, advisable to reserve expressing any definite opinion of its merits until further information is received, or until the burner has been tried in this country. CHAPTER VII. CONCLUSION. The burners last mentioned may be said to mark the extent of the progress that has been made, down to the present time, in the construction of apparatus for developing light from coal gas; and they remind me that I have arrived at the conclusion of my subject. From the unpretending gas-jet described by Accum--burning, with wonder-provoking steadiness and constancy, "so long as the supply of gas continued"--to the complicated apparatus of M. Clamond, is a long stretch of invention; embracing the labours of many distinct and original workers in the same field, and including numerous variations in the details of burners that have not been touched upon in the foregoing remarks. As was announced in the introduction, I have dealt in this treatise only with the more important or the more successful of the modifications that have been made from time to time in the construction of the gas-burner. In addition to the burners that have been referred to, there have been invented many others, which could not be adequately noticed without prolonging the treatise to an undue length. Some of these (the fruit of much thought and careful experiment) have obtained, in the commercial success that has attended them, no more than their merited reward; others (devoid of any real merit, and in their construction disregarding the most elementary principles of economic combustion) have been brought into somewhat extensive use by the misleading statements and false representations of their inventors, and are only tolerated through the ignorance of the public; while not a few of the latter class of burners have speedily found the oblivion which they richly deserved. Sufficient,