28 Mr. J. N. Lockyer. Comparison of the Spectra of [Dec. 19, 



December 19, 1889. 



Sir G-. GABRIEL STOKES, Bart., President, in the Chair. 



The Presents received were laid on the table, and thanks ordered 

 for them. 



The following Papers were read : — 



I. "Comparison of the Spectra of Nebulae and Stars of Groups 

 I and II with those of Comets and Aurorse." By J. Norman 

 Lockyer, F.R.S. Received November 9, 1889. 



The discussion of cometary spectra which was communicated to the 

 Royal Society in November, 1888,* contained, among other matters, 

 conclusions which have a special bearing on the relations of their 

 spectra to those of other bodies. 



I have thought it therefore desirable to bring this new material 

 together with the more complete lists of lines which are now avail- 

 able in the case of other groups of celestial bodies, chiefly owing to 

 the observations made by my assistants and others and myself since 

 my paper of 1887 was written, bat also in consequence of a more 

 complete search among previously recorded observations. 



Such a comparison — a much more complete one than was possible 

 in the first instance — would strengthen or weaken my hypothesis 

 according as the increased area of observation increased or decreased 

 the number of coincidences in the spectra of the various groups. 



The more the coincidences are intensified the greater is the proba- 

 bility that comets, nebulae, stars with bright lines, stars with mixed 

 flutings, and the aurora have a common origin, independent of the 

 chemical origins which have been assigned to the various lines by 

 laboratory observations. 



In the tables which follow, the individual observations are not 

 given, but under each heading all the lines or flutings which have 

 been recorded find place. 



I. Comparison of Comets and Nebula. 



We may conveniently begin with a comparison of comets and 

 nebulae. The Great Comet of 1882 and Comet Wells, when near 

 perihelion, are excluded from the list of cometary lines and flutings, 

 as their temperature was too high for fair comparison with most of 

 the nebulae and other low temperature phenomena. 



* ' Roy. Soc. Proc./ vol. 45, pp. 159—217. 



