430 Proceedings of the Asiatic Society. [No. 4, 



Dr. Bronn in Mr. Darwin's well known chapter on the " Struggle for 

 Existence." 



The hypothesis to which we had to apply these conditions was, 

 that of an originally fluid globe, cooling by radiation, until a solid 

 crust had formed, upon which the greater part of the water had 

 condensed in the form of seas, while the atmosphere contained a 

 larger proportion of aqueous vapour and carbonic acid than at 

 present. 



The excess of carbonic acid was subsequently fixed in the form of 

 limestone, and eliminated, especially during the coal period, by the 

 luxuriant vegetation which abstracted the carbon stored up in the 

 coal formed of its remains. The carbonic acid since converted into 

 coal and limestone had been calculated by Brogniart and Bischof 

 to amount to 6 per cent, of the entire atmosphere, or one hundred 

 times its actual proportion ; and although it is probable that it never 

 reached this amount, and that much of it was evolved from the 

 interior of the earth through volcanic vents, contemporaneously 

 with its absorption by the vegetation of the epoch, still, it had been 

 proved by the experiments of Daubeng and Begnault, that a propor- 

 tion of 5 per cent, of carbonic acid was by no means injurious to ferns, 

 and that provided sufficient oxygen were present, animals could live 

 without apparent inconvenience in an atmosphere containing half its 

 volume of the former gas. The surface of the earth being then in 

 such a condition as to support animal and vegetable life, we might 

 expect, according to Dr. Bronn, the following series of phenomena, 

 which, ranged in parallel columns exhibit the historic interdependence 

 of the organic and inorganic kingdoms. 



1. The simultaneous appear- 1. When by condensation and 

 ance of plants and animals, to chemical absorption the atmos- 

 sustain a proper relation in the phere became fitted to support 

 components of the atmosphere, life. 



2. An universal and continuous 2. As the temperature universal- 

 change in the fauna and flora of ly and continuously diminished, 

 the earth, 



a. The primary fauna and flora a. The temperature of the 

 were universal and tropical, earth's surface was likewise uni- 



form and tropical, until, 



