CuAP. I.] INEIITION. 11 



earth moving round the sun, but that the sun, carry- 

 ing with it the earth and the whole solar system, is 

 itself moving along among the fixed stars. But 

 though astronomical observations have demonstrated 

 the existence of this motion, neither its direction nor 

 its velocity has been clearly defined ; and as regards 

 any motion which the solar system may, for aught 

 we know to the contrary, partake in common with 

 the stellar system, the distance to which our range 

 of vision has been extended by the telescope is not 

 sufiicient to enable us to obtain any direct informa- 

 tion from the science of astronomy.^ 



' In the treatise on Vis-Inertiae already alluded to, as also 

 in this work, it is, however, shown that the evidences of the action 

 of vis-inertise in the ocean indicate a motion of the earth south- 

 wards ; and that the indications of the action of that force in the 

 outer crust of the earth corroborate the evidence of the ocean 

 currents. Those effects may be treated as if resulting from the 

 motion of the solar system. For, the effects of motion as shown 

 by tides, currents, and winds, will be the same whether those 

 effects result simply from a motion of the solar system in the 

 direction of the south pole, or be the average result of a 

 motion of the solar system in the direction of the north 

 pole combined with a motion of a more extensive system 

 with a greater velocity in the opposite direction. That is to 

 say, as far as the present question is concerned, those effects 

 might either result from a motion of the solar system by which 

 the earth is moved together with that system ; sweeping along 

 among the stars which compose the visible part of the universe, 

 and so changing its position among those stars ; or, they might 

 be the result of a motion of the whole stellar system, in which 

 the earth, the sun and the stars, equally partake as particles of 

 that system ; the motion demonstrated in the direction of the 

 south pole being, in such case, a majestic movement in Avhich the 

 whole visible universe is travellinEf onwards in that direction. 



