1884.] Spectroscopic Studies on Gaseous Explosions. 471 



leads, for it shows the necessity of making them large enough to 

 prevent the possibility of their being heated above normal tempera- 

 tures, otherwise points of danger are very easily reached by increments 

 of current. 



III. " Spectroscopic Studies on Gaseous Explosions. No. I." By 

 G. D. Liveing, M.A., F.R.S., and James Dewar, M.A., F.R.S., 

 Professors in the University of Cambridge. Received 

 March 28, 1884. 



Having occasion to observe the spectrum of the flash of a mixture 

 of hydrogen and oxygen fired in a Cavendish eudiometer, we were 

 struck by the brightness, not only of the ubiquitous yellow sodium 

 line, but of the blue calcium line and the orange and green bands of 

 lime, as well as of other lines which were not identified. The eudio- 

 meter being at first clean and dry, the calcium must be derived either 

 from the glass or from some spray of the water over which the gases 

 with which the eudiometer was filled had been confined. It seemed 

 incredible that the momentary flash should detach and light up lime 

 from the glass, but subsequent observations have pointed to that con- 



