ON THE SHORES OF THE ISTHMUS OF PANAMA. 48 



corroborates the evidence deduced independently from 

 other facts ; for it simply shows that the northward 

 pressure, resulting from the motion of the solar sys- 

 tem through space, is greater than the westward 

 pressure resulting from the axial rotation of the 

 earth, even in ths equatorial regions. 



If the solar system be moving in the direction of 

 the south pole, then the average level of the South 

 Pacific must, according to sections 129 and 130, vol. i., 

 be higher than that of the North Atlantic ;' inasmuch 

 as the attraction tide in the southern hemisphere is 

 higher than the vis inertias tide in the northern hemi- 

 sphere. And also, the force of vis inertias acting 

 northwards through the vast mass of water which 

 forms the South Pacific must tend to cause a heaping 

 up of the water on the Pacific coast of the Isthmus of 

 Panama. And if the level of the water on the 

 Pacific side of the Isthmus be higher than that of 

 the water on the Atlantic side, then it follows that 

 the northward pressure in the South Pacific, which 

 tends to heap up the water against the Isthmus 

 of Panama, is greater than the westward pressure 

 which tends to depress the level of that part of the 

 ocean. 



As far as this difference in level about the shores of 

 the isthmus is concerned : if a difference of level be 

 alone considered apart from all other considerations, 

 then it may be urged that a force of attraction draw- 

 ing in the direction of the North Pole might, by 



