TIDE RAISED BY ORBITAL FORCE. 7 



of an annual tide alternately ebbing and flowing 

 between the northern and southern hemispheres at 

 the periods stated in section 15 of vol. i. 



Since, however, the more marked of the phenomena 

 which should result from the action of such a tide 

 have by high authority been otherwise accounted for, 

 and the existence of such a tide necessitates the 

 rejection of theories which have been received with a 

 confidence which amounts to a conviction of their 

 correctness: we will first consider whether or not 

 any eiFects which should manifestly result from the 

 action of such a tide have been observed, and, re- 

 maining hitherto unaccounted for, have found a place 

 in the records of ascertained facts. But this is a 

 point which, from the great complication of forces in 

 play, is more intricate than might at first sight be 

 supposed; and we will therefore, whilst proceeding 

 with it, make a general survey of ascertained facts, 

 and briefly consider to what extent the effects of the 

 forces which we have in our preceding chapters 

 partially discussed are apparent in the actual move- 

 ments of the ocean and the atmosphere. For this 

 purpose, we will select such recorded facts as appear 

 most suited, by means of an analysis of the causes, 

 from which they proceed, to elucidate the action of 

 those forces. 



