1879.] Mr. J. N. Lockyer. On Chromo spheric Lines. 283 



Millions of years. 



Lauren tian, Cambrian, and Silurian 200 



Old Red, Carboniferous, Permian, and New Red 200 

 Jurassic, Wealden, Cretaceous, Eocene, Mi- 

 ocene, Pliocene, and Post-pliocene 200 



600 



The concluding part of the paper consists of answers to objections. 

 The author contends that the facts adduced prove geological time to 

 be enormously in excess of the limits urged by some physicists, and 

 ample to allow on the hypothesis of evolution for all the changes 

 which have taken place in the organic world. 



VI. " Preliminary Note on the Substances which produce the 

 Chromospheric Lines." By J. Norman Lockyer, F.R.S. 

 Received December 24, 1878. 



Hitherto, when observations have been made of the lines visible in 

 the sun's chromosphere, by means of the method introduced by Janssen 

 and myself in 1868, the idea has been that we witness in solar storms 

 the ejection of vapours of metallic elements with which we are familiar 

 from the photosphere. 



A preliminary discussion of the vast store of observations recorded 

 by the Italian astronomers (chief among them Professor Tacchini), 

 Professor Young, and myself, has shown me that this view is in all 

 probability unsound. The lines observed are in almost all cases what 

 I have elsewhere termed and described as basic lines ; of these I only 

 need for the present refer to the following : — 



b z ascribed by Angstrom and Kirchoff to iron and nickel. 



o 



b± ,, Angstrom to magnesium and iron. 



o 



5268 by Angstrom to cobalt and iron. 



5269 5 , ,, calcium and iron. 

 5235 ,, ,, cobalt and iron. 

 5017 „ ,, nickel. 



4215 „ „ calcium, but to strontium by myself. 

 5416 an unnamed line. 



Hence, following out the reasoning employed in my previous 

 paper, the bright lines in the solar chromosphere are chiefly lines 

 due to the not yet isolated bases of the so-called elements, and the 

 solar phenomena in their totality are in all probability due to dissocia- 

 tion at the photospheric level, and association at higher levels. In 



x 2 



