280 Dr Andrew Fyfe on Coal Illumination. 



The following are the average results : — 



In the paper published in 1842, it was stated that the 

 most profitable way of consuming gas is by the Argand, pro- 

 perly constructed ; in other words, that for equal consumpts, 

 the greatest amount of light is given by the Argand ; next, 

 by the batwing; then by the fishtail ; and, lastly, by the jet, 

 which is the least economical ; and, consequently, lighting 

 by gas, is comparatively, for equal amount of light, by far 

 most expensive to those having recourse to this mode of 

 burning it, such as to those requiring small quantities. The 

 light, as then stated, was in the ratio of 100, 140, 160, 180. 

 In the trials now recorded, the results do not all correspond 

 with these. With the small fishtail and the Argand they do 

 so very nearly ; the burners used having been the same as 

 formerly. The others, such as the lai'ge fishtail, not for- 

 merly tried, is more economical than the small fishtail ; the 

 small batwing, also not formerly tried, is not more economi- 

 cal than the small fishtail, and much less so than the large 

 fishtail. The large batwing, the largest I have ever seen, 

 is equally economical with the Argand : I found it very 

 liable to smoke. The general results of these trials may, 

 however, be said to correspond with those previously given, 

 proving the accuracy of my former statement, that the jet 

 is the worst kind of burner, giving least light for the same 

 consumpt ; next come the fishtails, generally speaking ; then 

 the batwings of medium size ; and, lastly, the Argand. 



