220 Dr Fyfe en the Illuminating and Heating Power of 



that publifihed by Professor Brande in Phil. Trans. 1820, it 

 10 shewn, that, when an argand burner contains a few holes, 

 and at such a distance that the flames from them do not meet, 

 it may be considered as so many single jets ; but when the 

 holes are nearer, and the flames are united, then the combus- 

 tion is carried on differently ; hence the superior efficacy of 

 the burners now used compared with those formerly recom- 

 mended. By that now in general use, which has twenty- four 

 holes, of about the 40th of an inch in diameter, the flame, 

 however short, is one continued ring, and, when high, there is 

 little of the blue flame, shewing that the gas is properly con- 

 sumed, so as to afford a comparatively great amount of light. 



One of these argands of twenty-four holes l-40th of an inch, 

 the diameter of the circle of holes being 7-8ths of an inch, and 

 the diameter of the central air aperture 6-8ths of an inch, was 

 compared with the standard jet of five inches ; and burning one 

 foot per hour. I found that, when the flame was only 1^ inch, 



The consumpt was as . 1 jet to 3.4 argand 



The light . . . 1 ... 2.65 



With another of the same kind, the flame being If of an 

 inch, 



The consumpt was as . 1 jet to 3 argand 

 The light . . . 1 ... 2.85 



In both of these trials, there was a loss compared with the 

 light given by the jet, — thus confirming the experiments of 

 Christison and Turner already alluded to.* 



With the same burner used in the last experiment, when 

 the flame was raised to 2^ inches. 



The consumpt was as . . 1 to 3.75 

 The light, . . . . 1 to 5.512 



Now, as 3.75 : 5.512 : : 1 : 1.46 ; so that, in this case, there 

 was actually a gain of 46 per cent, for equal consumpt of gas. 

 The same burner, with a 3-inch flame, ;;; 



Consumpt, . . . . 1 to 4.137 

 Light, . . . . 1 to 7.441 



And as 4.137 : 7.441 : : 1 : 1.79— Gain 79 ; 



* The area of the apertures recommended by Drs Christison and Turner 

 is 1-32 of an inch, but about l-40th is that now generally used in this town. 



