444 L, Scemann on the Unity of Geological 



92. Rissa septentrionalis. 1 Do. 



93. Sterna macrura. 15 McKenzie River, Slave Lake, 



and Slave River. 



94. Columbus torquatus. 5 Fort Simpson and Peel's River. 



95. " arcticus. 6 Do. do. 



96. " septentrionalis. 2 Fort Good Hope. 



97. Podiceps Griseigena. 1 Peel's River. 



98. " cornutus. 2 Big Island. 



The names are from Prof. Baird's works on North American 

 zoology. The species marked with a star (*) remain during winter. 

 I may have made some mistakes in my identifications, but I do 

 not think many. 



B. R. Ross. 



ARTICLE XXXIII. — On the Unity of Geological Phenomena in 

 the Solar System; by L. S^mann. 



[From the Bull, de la Soc. Geologique de France for Feb. 4, 1861 ; 

 translated by T. Sterry Hunt, M.A., F.R.S.] 



The observations upon the solar eclipse of July 18, 1860, have 

 given rise among astronomers and physicists to some interesting 

 discussions upon the nature of the sun, which seem to merit the 

 attention of geologists. The opinion hitherto generally adopted 

 is founded upon the view suggested by Arago from his observa- 

 tions concerning the spots upon the sun. This great astronomer 

 conceived that by admitting a dark nucleus surrounded by a lu- 

 minous atmosphere or photosphere, it would be easy to explain 

 the luminous phenomena presented by the sun.* On the other 

 hand Leverrier, from the observations made in Algiers by the 

 scientific commission from the Paris Observatory, maintains that 

 the sun is luminous from the incandescence of its nucleus, and that 

 the variations in the intensity of the light at its surface may be 

 explained by atmospheric perturbations similar to those of our 

 own atmosphere. Mr. Leverrier is led to admit for the sun, at 

 least two atmospheres different in nature and in density, and it is 

 principally with regard to the external envelope, or rose-colored 

 atmosphere, which gives rise to the flames or luminous protuber- 

 ances, that there exists a difference of opinion among observers. 



[* This view of the constitution of the sun, so ingeniously defended by 

 Arago, (see Annuaire du Bureau des Longitudes for 1842, p. 510,) is by 

 Mm there called the theory of "William Herschel, who appears to have 

 first clearly defined it. — Translator.} 



