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A. BLYTT. 



[No- 1- 



imity of the poles, and is constricted in the tropics. Suess de- 

 clines to acknowledge any other upheavals than those produced 

 by folding, and believes that it is the sea which has flowed 

 towards lower latitudes. He indicates as a possible explanation, 

 changes in the length of the sidereal day and centrifugal 

 force. But this change should, then, have acted only on the 

 sea, and as the sea flowed towards the equator, the sidereal 

 day should, thus, have become considerably shorter in the 

 latest geological age. We shall subsequently see that there 

 is no reason whatever known to us, which could have produced 

 such an abbreviation of the day sufficient to explain what 

 Suess desires explained. The old doctrine of cooling is scarcely 

 sufficient to explain the relations upon which Howorth and 

 Suess lay stress. Even Suess who is a zealous adherent of the 

 doctrine of contraction is here obliged to seek another ex- 

 planation. 



Another theory however arises in our day, a doctrine that 

 is doubtless destined to take an important place in the study of 

 geology. It originally emanates from the celebrated Philosopher 

 J. Kant. In 1754 he wrote a Memoir : „Untersuchung der Frage 

 ob die Erde eine Veranderung ihrer Achsendrehung erlitten habe." 

 In it he shows that the sea, by reason of the lunar and solar 

 attraction, is in constant movement contrary to the direction of 

 the earth's daily rotation. The friction of the tidal-wave against 

 the sea-bottom and the coast deprives the rotation of a portion 

 of its energy, and acts continually in the same direction, so 

 that the sidereal day must, from this cause, always gradually 

 increase in length. 



The Moon always presents the same side to the Earth, be- 

 cause the terrestrial tidal action on the still liquid lunar mass 

 caused the rotation of the Moon to become continuously retarded 

 until at last the Moon has been compelled to always present the 

 same side to the Earth.' In the same way the Earth will, at 



