984 Transactions of the American Institute. 



There is one other result that must follow the truth of my h^-pothe- 

 tsis, too important to be omitted hei'e. 



Jt is well known that the motion of any body revolving about 

 another bod}', also in motion, is necessarily spiral, and therefore 

 the motion of the magnetic pole, revolving about the North pole, 

 and being governed alid controlled by the attraction of a body in 

 motion around which the earth is revolving, shall also be spiral, 

 never returning to exactly the same point. And hence because one 

 law and one force governs both the motion of the earth and the 

 revolution of the magnetic pole, therefore the polar axle of the 

 earth shall change its position with every revolution of the mag- 

 netic pole, in such manner that the present poles of the earth's axis, 

 in her diurnal revolutions, will, or may, at length reach the present 

 line of the equator, and the equator will then become the poles; 

 and thus the idea suggested by geology, that the present poles of 

 the earth have, at some time of the earth's existence, been an 

 equatorial region, becomes a problem solved, and reduced to a 

 aimple and undeniable truth. Not a doubt exists "in my mind that 

 &uch has been the fact and will be again; and I am not less satis- 

 lied that the glacial theory of Professor Agassiz, so far as the fact 

 is concerned, that parts of our own land, and of others in Europe 

 and elsewhere, have at some time been the country of glaciers, is 

 no longer a speculative idea, but a mathematically demonstrable 

 truth.* 



The early system of astronomy was, I think, incompetent to the 

 solution of a question like the revolution of the solar system; and 

 modern astronomy *has done so little towards it, that it must be 

 considered as yet open to examination and argument. I have hope, 

 therefore, that the suggestions here made may prove a step towards 

 a more perfect knowledge of it. 



Years ago, when I first thought of the subject here treated of, it 



•There is a truth known to astronomers, which I think strongly confirms this point of 

 my argument. It is this: In the longitude of Athens it is known that the sun in Cancer 

 does not come so far north, by nearly a degree, as it did two thousand years ago. Astrono- 

 mers have inferred therefrom that the tropics are narrowing, and the earth consequently 

 is drawing nearer to the sun. But this I think is a mistake, and that the phenomenon 

 mentioned proceeds from the change in the line of the equator, as I have explained it; 

 and that if we had the opportunity, two thousand years ago, of observing south on the 

 meridian of Athens, it would then appear that Capricorn has receded south to the same 

 extent as Cancer, and vice versa at the antipodes. It would also depend on what distance 

 the meridian of Athens may be from the point where the former line of the tropic would 

 bisect the present line, whether on some other meridian, distant from Athens, the sun's 

 recession may not have been much greater than is seen at Athens. But for all evidence 

 of this kind, the observations of astronomers are totally wanting. 



