148 



Mr. J. Norman Lockyer. 



March 25, 1897. 



The LORD LISTER, F.R.C.S., D.C.L.., President, in the Chair. 



Meeting for Discussion. 

 Subject : " The Chemical Constitution of the Stars." 



The following Paper and Notes were read in the course of the 

 discussion : — 



"On the Chemistry of the Hottest Stars." By J. NORMAN 

 Lockyer, C.B., F.R.S. Received March 8, 1897. 



[PlATES 1—3.] 



CONTENTS. 

 Paet I. 



I. Introduction. 



The criterion of long and short lines. 



Some short lines indicate the effects of high temperature. 



Flame, arc, and spark lines. 

 II. Application of the early results to the investigation of stellar spectra. 



General remarks. 



Eirst indications of relative stellar temperatures. 

 Comparison of terrestrial and stellar line spectra. 

 The loci of absorption in stellar atmospheres. 



III. Recent photographic investigations on the spectra of metals at high tem- 



peratures. 

 Iron. 

 Calcium. 

 Magnesium. 



IV. Application of the recent investigations to stellar spectra. 



Iron. 



General results with regard to iron. 



Calcium. 



Magnesium. 



General results with regard to calcium and magnesium. 

 V. On the occurrence of the lines of the cleveite gases and of hydrogen in the 

 hottest stars. 

 Important position of the cleveite gases. 

 Varying ir tensity of the cleveite lines. 

 Varying intensity of the lines of hydrogen. 



