Scientific Intelligence, — Geology. 186 



every year until I have distinctly made out every thing about the 

 matter, friendly society were much to be wished on a tour which 

 cannot well be made alone. — {Letter from M. Agassizin Leonhard 

 and BronrCs Jahrhuch^ dated September 18. 1839.) 



6. Origin of Fissures in Glaciers — At a recent meeting of the 

 Philomathic Society of Paris, M. Martins read a memoir on the 

 glaciers of Spitzbergen, compared with those of Switzerland and 

 Norway. This communication gave rise to a discussion on the 

 nature of the cause which produces the fractures in glaciers. M. 

 Martins attributes them to the unequal dilatation undergone by the 

 different parts of these masses of ice, combined with the manner in 

 which they are enclosed by the surrounding mountains. M. Elie 

 de Beaumont defended the opinion of geologists, who consider the 

 sliding of these masses of ice on inclined planes as the principal 

 cause of the fractures. He remarked, that the rents are precisely 

 in the direction of this sliding, that is to say, they are in a direc- 

 tion perpendicular to the axis of the valley, whereas they would 

 ba perfectly irregular if they were produced solely by unequal di- 

 latation in the different parts of the glacier. M. Martins replied 

 to this observation, that, first of all, imperceptible fissures are 

 formed in all directions, but that those having a transverse direc- 

 tion alone present the conditions necessary for enlargement ; that, 

 undoubtedly, the weight of the ice above contributes to the pheno- 

 menon, but that the greater part of the action ought to be attri- 

 buted to the water which falls into the fissures, and which, becoming 

 consolidated, acts as a wedge on their walls. 



7. Sefstrom's Investigations. — Sefstrbm continues his observations 

 on the furrows on rocks. The return is expected of one of his 

 scholars, who is occupied with similar investigations in the northern 

 portions and on the sea-jcoast of Norway. I cannot coincide with 

 the objections which have been made to the views of Sefstrom. 

 Although great rushes of accumulations of water have produced 

 the boulders and furrows of the Swiss valleys, yet this only proves 

 that boulders and furrows are produced exactly in the manner as- 

 sumed by Sefstrom. But we cannot thence draw the conclusion, 

 that the enormous rolled masses, and the almost unvaried direction 

 of the furrows, throughout the whole of Scandinavia and Finland, 

 owe their origin to such comparatively small accumulations of wa- 

 ter as exist in Switzerland. The high position of such accumula- 

 tions is entirely awanting in Scandinavia ; and how prodigious a 

 mass of water it must have been, that polished and furrowed over 

 all Sweden, hills of more than 300 feet in height. — Berzelius, in 

 Leo7)kard and Brcnns Jahrbuch. 



