132 Marie- Henri Ducrotay de Blainville. 



tacles this constantly growing supply of salt. By this equili- 

 brium between the drainage of a region and the evaporation, 

 the waters become at last so strongly impregnated as to 

 deposit or crystallise the salt upon their margins. Following 

 up the same general fact of the incessant solution of the 

 rocks, we behold in the sea itself a basin like the other salt 

 ones, which has no outlet for its surplus supplies, but back 

 again by evaporation into the atmosphere. Looking, then, 

 at the primeval condition of an atmosphere of aqueous vapour 

 just after the period when the earth's general temperature 

 was incomputable with this state of water, it was a fresh 

 ocean and not a salt one. 



Professor Agassiz remarked, that the facts and views 

 unfolded did, as the author said, furnish a new means of 

 interpreting the ancient climates of the globe. From the 

 fossil vegetable and animal organic remains, geologists have 

 long felt themselves provided with sensitive indexes of the 

 past temperatures of the earth at different periods, but never 

 until now had they been supplied with a hygrometer. This 

 Professor Rogers had furnished. 



In further confirmation of these views, Dr C. T. Jackson 

 stated, that the water of the river Jordan was found, upon 

 evaporation, to contain the same ingredients as the Dead Sea 

 into which it flowed. 



Marie-Henri Ducrotay de Blainville — Dr Pye Smith — and 

 M. Beudant. 



1. Marie-Henri Ducrotay de Blainville, member of the 

 Academy of Sciences in France, succeeded Lamarck as Pro- 

 fessor of Natural History in Paris, and was afterwards chosen 

 to replace Cuvier in the chair of Comparative Anatomy. His 

 exertions in these departments of science were pursued un- 

 interruptedly throughout half a century, and the catalogue of 

 his memoirs and works given by Agassiz in his " Bibliogra- 

 phia," amounts to no less a list than 150, — a list which might 

 have been enlarged, as I learn from M. Constant Prevost, to 

 180, none of them without merit, and some, like his " Manuel 

 de Malacologie et Conchologie," and his " Osteography of the 



