viii PREFACE. 



each other : which forces, being unknown, phi- 

 losophers have hitherto attempted the search 

 of nature in vain ; but I hope the princi- 

 ples here laid down will afford some light 

 either to that or some truer method of philo- 

 sophy.' 



The progress of knowledge appears to be 

 gradually demonstrating the correctness of the 

 opinion expressed in these sentences ; and their 

 appearance as a prefix to this volume will not 

 be considered inappropriate, if I am not mis- 

 taken in supposing that herein is shown the 

 mechanism which causes the stormy epochs in 

 the northern and southern hemispheres respec- 

 tively ; the mechanical cause of the annual 

 and diurnal oscillations of the barometer ; the 

 mechanical cause of the relative distribution 

 of land and water in the northern and 

 southern hemispheres ; and the mechanical 

 cause of certain marked peculiarities in the 

 conformation of the undulations and fractures 

 of the stratified surface of the earth. I offer 

 no further comment on them ; but con- 

 tinuing in the words of Sir Isaac Newton ' I 

 heartily beg that what I have here done may 



