158 Mr. J. N. Loekyer. On the Classification [Jan. 10, 



VII. Sequence of Phenomena in Cometary Spectra. 



VIII. More Detailed Discussion of Certain Comets, with Special Reference to 



Approach and Secession from Perihelion. 

 Comet Wells. 

 The Q-reat Comet of 1882. 

 Coggia's Comet. 

 Comet III, 1881. 

 Brorsen's Comet. 

 Winnecke's Comet in 1877. 



IX. Possible Causes of Collisions in Comets. 

 Internal Work. 

 External Work. 

 Collisions between Cometary and other Swarms. 



X. On Some Effects of Collisions in Comets. 

 XI. Conclusion. 



II. " ON SOME EFFECTS PBODTTCED BY THE FALL OF METEOBJTES ON THE 



EABTH." 

 Part I. Falling Dust. 



f Angstrom's First Observations. 



Zollner's View. 

 Vogel's View. 



Angstrom's further Observations and Conclusions, 

 j Comparison of the Aurora Spectrum with the Negative-pole Spectrum 



of Oxygen. 



Comparison with the Spectrum of Hydrogen. 

 Comparison with the Spectrum of Phosphoretted Hydrogen. 

 Groneman's reference to the Meteoric Dust Theory. 

 Mr. Capron's Conclusions. 

 II. Lemstrom's Observations. 



III. Gyllenskiold's Observations and Conclusions. 



IV. The Sequence of the Flutings and Lines seen in a Large Tube at 



different Stages of Pressure. 



V. Comparison with Uncondensed Meteor Swarms. 

 VI. Further Discussion of Gryllenskiold's Observations. 

 VII. The Norwegian Observations. 

 VIII. The Spectrum of Lightning. 

 IX. The Aurora and the Zodiacal Light. 



Part II. Fallen Dust. 



III. " SUGGESTIONS ON THE OEIGIN OF BINARY AND MULTIPLE SYSTEMS." 



I. Colour phenomena. 

 II. General Statement of Conditions. 

 III. Light curves. 

 IV. Binary Stars, Class 1. Equal Magnitudes and Similar Colours (not 



Yellow). 



V. Binary Stars, Class 2. Equal Magnitudes and Similar Colours (Yellow). 

 VI. Binary Stars, Class 3. Equal or Nearly Equal Magnitudes, one Star being 

 Blue. 



