different kinds of Coal-gas Burners^ Sfc. 227 



the gases. I may here merely remark, that, looking at the re- 

 sults of the trials now given, we may consider the argand as 

 by far the most economical way of consuming gas when illu- 

 mination is the only object in view ; besides, the appearance of 

 the burners naturally gives it a preference to others. As to 

 the kind of argand, that now in general use, with 24 holes 

 about one-fortieth of an inch, seems to answer the purpose 

 better than any other hitherto recommended, but the area of 

 the aperture must be increased or diminished a little according 

 to the illuminating power of the gas. Of course, much must 

 depend on the height of the flame and the kind of chimney. 

 For general purposes, the flame ought to be such, that the gas 

 will burn without smoke, and without the flame acquiring a 

 dingy hue. This will be found to be about three inches in 

 length. As to the chimney, it ought to be such as will supply 

 the air in due proportion, but not in excess, otherwise the gas is 

 not decomposed previous to its combustion, and consequently, 

 is burned unprofitably, but for particulars on these points, I 

 must refer to the paper by Christison and Turner.* 



For other purposes, the bat- wing or the fish-tail ought 

 to be preferred, as where it is not convenient to use chim- 

 neys, as in shops and manufactories. As to the single jet 

 burner, it is evidently the most unprofitable way in which gas 

 is consumed. Where the light required is not great, instead 

 of the single jet, a burner with three apertures on a line and 

 near each other, ought to be employed, because with these to 

 get the same light as with a jet a smaller quantity of gas is 

 requisite. 



II. — On the Comparative Heating Poioer of GaS'Burners.f 

 I have already mentioned that when gas is used for the 

 purpose of illumination, it is not merely necessary that it be 



* Since the experiments related in this paper were performed, a paper 

 has been published in the last number of the Journal, by Sir John Robison, 

 giving the results of his trials with argands of different kinds. To this 

 communication, the reader is referred for valuable information on the con- 

 struction of burners, and on the comparati\'e amount of light afforded by 

 them. The general results will be found to agree with those above recorded. 



t Read before the Society of Arts for Scotland, 13th May 1840. 



