DISCUSSION AND ANALYSIS OP WINDS. 



699 



In winter the pressure is even a little higher in this region than in summer, but 

 it is still higher to the northwest in the interior of the continent, and somewhat 

 lower in the adjoining part of the Atlantic. The mean direction of the wind is 

 then more northerly, or even northwesterly, as shown in the next table, and the 

 maps. Plates 7, 8, and 14. 









Spring. 



Summer. 



Autumn. 



Winter. 1 







a 





^ 





d 





^ 



P 





^ 



G 





.^ 











t.-. fl 















»« o 

























C =i 

















































B g 





:§'3 





5S 





s'a 



s 





B"^ 



" S 





19 



















« " 



















g^ 





p-^ 





g^ 





K " 



g^o 





M'- 



g^ 





w 



N. E. Florida 



S. 



62° 



W. 



.18^ 



S. 



2° 



W. 



.27 



N. 15° 



E. 



.23 



N. 38° 



W.L2S 1 



Florida, 29°-30° N. L. . 







N. 



87 



E. 



•03^ 



s. 



33 



E. 



.23 



N. 47 



E. 



.34 



N. 3 



E. 



.15i 



S. W. Florida, S. of 29° N. L. 







N. 



18 



W. 



Jli- 



s. 



77 



E. 



.09 



N. 27 



E. 



.37 



N. 19 



E. 



.25i 



S. E. Florida, S. of 29° N. L. 







S. 



82 



E. 



.22 



s. 



64 



E. 



.54 



N. 61 



E. 



.44 



N. 69 



E. 



.28 



Northern Bahamas 







N. 



78 



E. 



.42 



s. 



67 



E. 



.62 



N. 67 



E. 



.51 



N. 73 



E. 



.37 



Florida Keys 







N 



76 



E. 



.31 



s. 



66 



E. 



.47 



N. 64 



E. 



.50 



N. 52 



E. 



.46 



W. Florida .... 







S. 



39 



W. 



.16 



s. 



47 



W. 



.19 



N. 32 



E. 



.15^ 



N. 10 



W.'.23 



Alabama, 31°-32° N. L. 







S. 



l(j 



E. 



.05 



s. 



5 



E. 



.04^ 



N. 39 



E. 



.30A 



N. 12 



W.'.17i 



Alabama, 32°-33° N. L. 







S. 



51 



w. 



.11 



s. 



2 



W. 



.12 



N. 31 



E. 



.09 



N. 54 



w.'.og^ 



Alabama, 33°-34° N. L. 







S. 



81 



W. 



.22 



s. 



51 



E. 



.12 



N. 68 



W. 



.04 



N. 5S 



W. .16 



Mississippi and Alabama, S. of 31° 



N. L 





S. 



3 



E. 



.15 



s. 



3 



E. 



.08 



i N. 40 



E. 



.27 



N. 14 



E. ;.i6 



Mississippi, 31°-32° N. L. . 







S. 



12 



W. 



.14J 



s. 



15 



W. 



.18 



N. 30 



E. 



.09 



S. 41 



W. .02 



Mississippi, 33°-34° N. L. . . 







S. 



58 



W. 



.06 



s. 



11 



E. 



.01 



N. 33 



E. 



.13 



N. 28 



E. '.04 



Mississippi, 34°-35° N. L. . 







S. 



53 



W. 



.10-1 



s. 



4 



W. 



•31i 



S. 62 



W 



.16-1 



S. 78 



W. .28i 



N. E. Louisiana 







S. 



29 



E. 



.19 



s. 



9 



E. 



• 23i 



N. 58 



E. 



.18 



N. 61 



E. .15 



E. Louisiana, 30°-31° N. L. . 







S. 



51 



E. 



.16 



s. 



46 



E. 



.20i 



S. 64 



E. 



.30i 



N. 70 



E. .21 



S. E. Loaisiana 







S. 



Gd 



E. 



.15 



s. 



21 



E. 



.23' 



N. 53 



E. 



.31 



N. 41 



E. .21 



The Florida Keys and the Northern Bahamas belong approximately to the trade- 

 wind region, though, owing to the powerful influence of the continent, the winds 

 are E. S. E. in summer. But this is also the case in the West Indies. In the other 

 seasons the mean direction is nearly E. N. E., and the ratio great, though certainly 

 not so great as further south, in the middle of the ocean, where it often attains from 

 .80 to .90, The same may be said of S. E. Florida, only the winds are less regular, 

 as is seen by the smallness of the ratio of resultant. 



On the northern shore of the Gulf of Mexico, and to about 32° N. L., the winds 

 are northeasterly in autumn, but the ratio of resultant is so small as not to warrant 

 the calling of this a region of trade-winds. Pressure is high at this season, and a 

 little lower on the Gulf, but the difference is very small. Besides this, the variations 

 of pressure and temperature are great here in winter. When a belt of low pres- 

 sure, a storm-centre, reaches the upper Mississippi, air is drawn from the Gulf to 

 supply the deficiency. South winds, with high temperature and abundant pre- 

 cipitation, are the result. In spring and summer the Gulf States have southerly 

 winds from the Atlantic and the Gulf They then prevail to a greater extent than 

 the northeasterly winds of winter. 



I give below the mean direction for the year, and the ratio of resultant, to show 

 how nearly balanced are the different directions, except in the Northern Bahamas, 

 Florida Keys, and S. E. Florida, where the N. E. movement is well marked. (See 

 also Plate 3.) 



