Proximate Causes of certain Winds ami Storms. 253 



1781 and 1792, so that Daniell may have had access to documents 

 by which his assertions were fully warranted. 



(c.) It is stated in the Encyclopedia Perthensis, that at St- Peters- 

 burg the northerly winds were found during a term of sixteen years, 

 to be to the southerly as 133 to 119, (the westerly were to the eas- 

 terly as 133 to 92,) and that in the Mediterranean the north wind 

 Mows for nearly three fourths of the year. Other citations might be 

 made from the same quarter, but their bearing upon the question be- 

 fore us is, doubtful, as merely the point from which the wind blows 

 during the greatest number of days is specified without any notices, by 

 which the relative proportion of northerly and southerly winds may 

 be determined. 



(d.) In that part of the Atlantic Ocean lying beyond the northern 

 limit of the trade winds between the United States and Europe, it 

 appears that southerly winds predominate.* Their cause is proba- 

 bly analogous to that of the Gulf Stream. 



{e.) Of the meteorological registers that have been published in 

 this Journal, some, as those of Messrs. Field, Olmsted and Wa Hen- 

 stein, shew an excess of northerly winds; others as those of Drs. 

 Beck, Lovell, and probably Hildreth, an excess of southerly winds, 

 but in general, the- excess of the southerly over the northerly where 

 it obtains, is less than that of the westerly over the easterly. Thus, 

 in the abstract of Dr. Lovell, the westerly winds are to the easterly 

 as 12.59 to 9.63 — the southerly to the northerly as 12.59 to 11.60. 

 On the whole there can be little room for doubt, that the winds from 

 the north predominate over those from the south within the limits of 

 the United States. This method of estimating the amount of wind 

 in any direction, by the number of days it blows from that point, is 

 exceedingly defective, and may (as where the wind is commonly vi- 

 olent in one direction and gentle in another, and the force with which 

 it blows is altogether neglected,) lead to the most erroneous results. 

 This happens to be the case in this country. Our south west winds 

 prevail chiefly in the summer season ; they are mild breezes, sub- 

 siding often into a calm, which continues during a considerable part 

 of the day. Our north west winds on the other hand, sweep over 

 the continent day and night, with a constancy and velocity, which ren- 

 ders it necessary to make a considerable allowance when we are es- 



See rhe quotation from V on Buch. 



Vol. XIX.— No. 2. 33 



