84 



INORGANIC EVOLUTION. 



[CHAP. 



strong electric current. We observe no rhythm, and there seems to 

 be a very irregular distribution (Fig. 31). 



I may here state that it has always been customary with me in 

 reproducing spectra in the form of illustrations to show the red end 



ir 



, 



02 



of the spectrum on the right hand side and the violet end on the 

 left. As most of the workers on "series" do the opposite, seeing 

 that they have to deal with the numbers of waves instead of their 

 length, I propose in this chapter to depart from my usual custom 



