232 Wisconsin Academy of Sciences^ Arts, and Letters. 



declination neither do the highest tides occur at fall and change 

 of the moon, nor the least tides in the quadratures. 



A singular fact in nature, which is attributable to the tides, is 

 the existence of the Sargossa seas in mid ocean. The tide in mid 

 ocean is very small as has been ascertained at islands along the 

 course of the tide. At the shores however, the tide is retarded 

 and its range increased, so that the surface of the ocean is practi- 

 cally lower than its limits, forming a sort of settling basin whence 

 the singular seas. A current chart by Bowditch shows a current 

 from all directions towards the Sargossa sea in the Atlantic. 



There is another question which arises and that is, why, if there 

 is a primary tide in each of the southern oceans, there is not also 

 the same in the northern oceans ? 



In the first place, the southern oceans are the largest and deep- 

 est and the effect produced upon them would preponderate over 

 that produced on the smaller oceans. In the second place, the 

 origin was not a matter of chance or choice but necessity, for as 

 soon as the condensation of aqueous matter was sufficient to fill 

 or to partly fill an oceanic basin, the tides began to move and as 

 the oceans continued to increase, the motion was imparted to the 

 increasing waters, the regularity of the impulse had the effect of 

 producing the regular succession of tides of the oceans as the 

 earth in its diurnal revolutions presented them successively to 

 the tide producing force. 



To sum up this investigation we have : 



First. A primary tide in each of the southern oceans, and one 

 in the Arctic ocean. These rise twice a day, and their appear- 

 ance corresponds in time exactly with the moon's apparent motion. 

 The semi-diurnal tides differ in magnitude with the moon's de- 

 clination from the equator, showing that there is a tide force 

 ■under the moon and also one on the remote side of the earth giv- 

 ing a tide following the inferior as well as the superior transit of 

 the moon. The tides are greatest at the full and change and 

 least at quadratures, and the range varies perceptibly with the 

 distance of the moon. 



Second. The moon revolves about the earth in an eliptical 

 orbit, and by mutual attraction both revolve about a common' 



