OF THE EARTH S AXIAL ROTATION. 5 



human race will perhaps not reach the tenth part of that 

 time, yet the mere certainty of this impending fate and 

 the constant approach of nature to it, is an object worthy 

 of our admiration and examination. 



If the celestial space were filled with matter that offered 

 some measure of resistance, the daily Rotation of the 

 Earth in it would find a constant hindrance by whicn its 

 rapidity could not but be gradually consumed and finally 

 exhausted. But such resistance is not to be taken into 

 account, since Newton has shown in a convincing manner 

 that the celestial space, which allows a free unhindered 

 motion to the light vapours of comets, is filled with in- 

 finitely less resisting matter. Besides this improbable 

 hindrance, there is no other cause which can have an 

 influence upon the motion of the earth but the attraction 

 of the moon and of the sun ; and as it is the universal 

 driving power of nature the power from which Newton 

 has evolved her secrets in such a clear and indubitable 

 way it furnishes a reliable foundation upon which we 

 may here base a sure examination and proof. 



If the Earth were a wholly solid mass without any 

 fluid elements, neither the attraction of the sun nor of 

 the moon would do anything to alter its free axial rota- 

 tion. For it draws the eastern as well as the western 

 parts of the terrestrial globe with the same force, and 

 causes thereby no inclination either to the one side or 

 the other, and consequently it leaves the earth in complete 

 freedom to continue its rotation unhindered, just as if it 

 were subject to no external influence. But taking it to 

 be the case that the mass of the planet comprises in it 

 a considerable quantity of the fluid element, then the 

 combined attractions of the moon and the sun, by moving 



