44 On the Terrestrial Arrangements connected with 



state in which it would be composed of a solid exterior shell, 

 and a solid central nucleus, with matter in a state of fusion 

 betwixt them — a state, in short, similar to that indicated in 

 figure 2, supposing the central space, N, to be filled up with 

 solid matter. 



On the Terrestrial Arrangements connectedwith the Appearance 

 of Man on the Earth: heing the substance of a Lecture de- 

 livered by Professor Gustav Bischof of Bonn, at Bonn. 



I. Coal and Soil. 



Coal. Evaporation goes on the more rapidly the higher the 

 temperature of the sea and of the surrounding atmosphere. The 

 southern seas are, therefore, much more productive of vapours 

 than those situated farther to the north. Moreover, during 

 the earliest geological periods, when the amount of heat diffused 

 over the earth was comparatively greater than at present, the 

 quantity of atmospheric moisture must have been much more 

 considerable. 



We have, in one of our former lectures, pointed out the 

 surprising grandeur and luxuriance which characterised the 

 vegetation that was destined to furnish the materials for the 

 formation of our immense beds of coal. Whence comes this 

 luxuriant growth of plants ? Because the two main conditions 

 of vegetable life, heat and moisture, were then much more 

 copiously diffused than they are at present. 



It has also been observed in one of our former lectures, that 

 the ocean covered a much larger space ages ago ; and that ex- 

 tensive countries now raised above the sea, were then but in- 

 considerable islands. The ocean yielded a greater amount of 

 vapours, not only because it was warmer, but because it pre- 

 sented a larger surface. These, then, were the principal 

 causes active in the production of a very great early vegeta- 

 tion. It has been incontestibly proved, that at one time the 

 whole earth, with the exception of a few islands, must have 

 been covered by the waters of the ocean. We shall here make 

 a few remarks on this subject. If, for instance, our Rhine 



