34 



PROCEEDINGS OF THE AMERICAN ACADEMY 



or fresh winds, but that it fell m .080 by violent winds from the north 

 to northeast, and rose the same quantity by those from the south- 

 west, the south, or the southeast. (Comptes Rendus de VAcademie des 

 Sciences, Tom. III. p.^.36.) We have, therefore, reason to suppose that 

 the variations in the prevailing winds in the different seasons of the year, 

 since their averages or resultants cannot amount to more than a very 

 gentle wind, can have but a small effect upon the mean level at Brest. 

 Moreover, the winds from the south and southwest, which tend to cause 

 a rise in the mean level, prevail the most, and with the greatest force, 

 during the winter and spring, and hence cannot cause the preceding 

 corrected variation of mean level, which is at its minimum during that 

 time. There must, therefore, be yet some other cause affecting the 

 mean level of the sea at Brest. 



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With regard to the effect of the winds on the mean level of the sea 

 at Key West, Dr. Bache remarks, that " winds tending to elevate the 

 water in the harbor prevail for six months, from March to August 



