TJie Length of Flame in Explosions. 169 



On the Length of Flame Produced by the Explosion of 

 Gases in Tubes. By B. Lean, B.Sc, Dalton Chemi- 

 cal Scholar; and H. B. Dixon, M.A., F.R.S., Pro- 

 fessor of Chemistry in the Owens College. 



{Received February 21st, iSgj.) 



While many measurements have been made on the 

 pressures produced by the explosion of gases, and also on 

 the rates with which the flame is propagated in different 

 mixtures, we know of few experiments on the extension of 

 the flame, i.e., the distance to which the flame may be forced 

 beyond the original limit of the explosive gases. 



In a paper, read before this Society in 1891,* we described 

 some experiments on the transmission of flame across an 

 air-gap between two explosive mixtures of gases. We 

 found that the enclosed air was, to a large extent, pushed 

 bodily forward like a plug, so that a comparatively short 

 •column of inert gas prevented the flame from penetrating 

 to and igniting the explosive mixture beyond. In the 

 present series of experiments we made observations on the 

 distance to which the flame extended along a tube com- 

 municating at one end with the column of explosive gases, 

 and at the other end open to the air. Our main object being 

 to obtain data as to the extension of flame in the explosion 

 of mixtures of fire-damp and air in mines, we used (instead 

 of electrolytic gas, as in our former experiments) various 

 mixtures of air and of coal-gas, which resembles fire-damp 

 in its mode of burning with air. 



In the great majority of the experiments, the explosive 

 mixture was introduced into a brass tube, about 2ft. in 

 length and of 15 mm. internal diameter. At one end it was 



• Memoirs Lit, and Phil. Soc. [Fourth Series], Vol. V., p. 16. 



