TRANSLATOR'S INTRODUCTION Iv 



common, constant physical processes that have been effect- 

 ing the great changes of the Earth's surface all along. Kant 

 clearly states and discusses the four theories or causes 

 assigned at that time to explain the gradual wearing out of 

 the present terrestrial system, and the consequent ageing of 

 the Earth ; and even through his discussion of their imper- 

 fect data, while admitting the contingencies of occasional 

 volcanic catastrophes, he anticipates the view of the rela- 

 tively uniform action of the existing physical causes in 

 altering the physical conditions of the Earth, as worked out 

 by Lyell in his Principles of Geology nearly a hundred years 

 later, and now adopted by all geologists and physiographers. 

 He is particularly strong in his clear description of the in- 

 fluence of rain-water in denuding and lowering the upper 

 lands, and thus forming lower fertile regions by the deposits 

 of flowing streams. He does not attempt to determine pre- 

 cisely the Age of the Earth, but is content with merely 

 indicating observations and investigations which are set in 

 that direction, and which already virtually demonstrate not 

 only the ageing, but the gradual dissolution of the present 

 system of things. These two minor Essays of 1754 were 

 really ' chips ' struck off during the process of working out 

 the Cosmogony; and the discussion of the Ageing of the 

 Earth presents itself as the transition to the greater 

 work, from the earlier announcement of it in the discussion 

 of the Retardation of the Earth's Rotation. 



V. KANT'S ' NATURAL HISTORY AND THEORY OF 

 THE HEAVENS/ 



I. Publication. The last word of the paper on 

 the rotation of the Earth was the announcement of 

 the forthcoming publication of the Cosmogony, which 

 was printed and ready for publication in the spring 



