142 BIOGKAPHIES OF SCIENTIFIC MEN 



myself." However, he was always willing to hear the 

 opinions of others, and to admire their work. 



In 1733, four years after the death of Jean Gaston, 

 Grand Duke of Tuscany (the last of the De Medicis), 

 Buffon was elected a member of the Academic des Sciences. 



He greatly improved and enlarged the much neglected 

 Jardin des Plantes, having been appointed the director, 

 and continued the work of regeneration begun by Dufay. 



In 1744 Buffon published his Theorie de la Terre, 

 which was ultimately included in the Histoire Naturelle. 

 He had similar ideas to those of Laplace and Kant, 

 namely, that the earth and other planets were thrown off 

 from the sun in the molten state, and, after cooling, dry 

 land, seas, mountains, etc., were formed by various agencies 

 that are slowly working at the present day. Concerning 

 the place where life began on this planet, he suggested, 

 in his l&poyue* de la Nature, the polar regions. 



As the globe cooled, those regions would be the first to reach a 

 temperature under which life is possible. The Comte de Saporta, 

 whose researches give large support to Buffon's theory, remarks that 

 the richest fossil-yielding rocks are found in northern latitudes of 

 50 to 60 and beyond, and show that as far back as Silurian times the 

 North Pole was warm enough to maintain life of a tropical character, 

 and that it was the centre of origin of successive forms down to the 

 Tertiary epoch; the Miocene flora, which has now to be sought 40 

 farther south, being profusely represented. In Carboniferous times a 

 warm, moist, equable climate prevailed over the whole globe, due, as 

 De Saporta argues, to arrest of radiation by a highly vaporous atmo- 

 sphere, and also, perhaps, to the greater diffuseness of the sun's light 

 by reason of his larger volume. 



