DISCUSSION AND ANALYSIS OF WINDS. 711 



extensive in Africa, and more heated, the ascending current is, therefore, more 



powerful, and thus the air from over the cold current is attracted with more force. 



The mean direction of the wind in the tropical part of the Atlantic is as follows: — 









June to August. 





Deo. 



to Feb. 







Junet 



D August. 



Dec. to Feb. 



1 





(w 5 





B 





■sl' 





c 





•sl 





1 



o1 









§ 





^9 





1^ 



















re's 







S'5 



Zoue 14. 



60°-80° 



W. 



S. 88° 



E. 



.77 



N. 



73° 



E. 



.51 



Zone 23. 



40°-45° W. 



N 



66° 



E. 



.36 



N 



58° E. 



.44 



" 14. 



40 -50 



W. 



N. 58 



E. 



.75 



N. 



63 



E. 



.55 



" 23. 



20 -25 W. 



S. 



65 



E. 



.46 



N 



85 E. 



.55 



" 14. 



15 -25 



W. 



N. 27 



E. 



.79 



N. 



51 



E. 



.58 



" 23. 



- 5 E. 



S. 



28 



E. 



.65 



S. 



29 E. 



.63 



" 15. 



60 -80 



W. 



N. 89 



E. 



.84 



N. 



66 



E. 



.80 



" 22. 



35 -39 W. 



s. 



61 



E. 



.67 



N 



72 E. 



.72 



" 15. 



45 -50 



W. 



N. 60 



E. 



.77 



N. 



64 



E. 



.73 



" 22. 



10 -20 W. 



s. 



55 



E. 



.79 



S. 



61 E. 



.80 



" 15. 



15 -25 



W. 



N. 42 



E. 



.91 



N. 



31 



E. 



.76 



" 22. 



-121 E. 



s. 



26 



E. 



.84 



s. 



35 E. 



.96 



" 16. 



45 -50 



W. 



N. 55 



E. 



.90 



N. 



49 



E. 



.86 



" 21. 



35 -39 E. 



s. 



50 



E. 



.79 



s. 



87 E. 



.83 



" 16. 



30 -35 



W. 



N. 72 



E. 



.55 



N. 



68 



E. 



.87 



" 21. 



15 -25 W. 



s. 



48 



E. 



.92 



s. 



84° E. 



.98 



" 16. 



15 -25 



w. 



N. 10 



E. 



.18 



N. 



37 



E. 



.77 



" 21. 



5 W. 13 E. 



s. 



6 



E. 



.63 



s. 



45 E. 



.100 



" 17. 



45 -50 



w. 



N. 66 



E. 



.56 



N. 



50 



E. 



.91 



" 20. 



33 -35 W. 



s. 



46 



E. 



.89 



s. 



75 E. 



.83 



" 17. 



30 -35 



w. 



S. 49 



E. 



.05 



N. 



65 



E. 



.38 



« 20. 



15 -20 W. 



s. 



47 



E. 



.96 



s. 



45 E. 



.96 



" 17. 



10 -20 



w. 



S. 4 



W. 



.88 



N. 



9 



W. 



.31 



« 20. 



15 W. 10 E. 



s. 



11 



E. 



.68 



s. 



11 W. 



.59 



" 18. 



40 -55 



w. 



S. 55 



E. 



.82 



N. 



73 



E. 



.74 



« 19. 



35 -45 W. 



s. 



48 



E. 



.85 



s. 



62 E. 



.88 



" 18. 



30 -35 



w. 



S. 62 



E. 



.70 



N. 



87 



E. 



.69 



" 19. 



20 -25 W. 



s. 



43 



E. 



.92 



s. 



35 E. 



.89 



« 18. 



10 -20 



w. 



S. 13 



E. 



.83 



S. 



29 



E. 



.34 



" 19. 



15 W. 11 E. 



s. 



6 



E. 



.73 



s. 



16 W. 



.67 



(See also Plates 5, 6, and 14.) 



This table is so arranged as to show the corresponding latitudes north and south 

 opposite to one another. It will be seen how much more regular are the southern 

 trades, especially between 0°-15°. 



In the northern hemisphere the trades are well established between 10°-15° N. 

 in the middle and western part of the ocean ; while near the African coast the 

 winds are very variable, or better to say this latitude is divided in summer between 

 the N. E. trade and the S. W. monsoon. In the corresponding latitude south, the 

 S. E. trade is blowing regularly the whole year. 



In latitude 5°-10° N. the S. E. trade is already established in the middle of the 

 ocean from June to August and the African monsoon in full force further east. 

 In the corresponding latitude in the southern hemisphere the trade is very regular. 

 It is also blowing between 0°-5° N. with the exception of the months fi-om Decem- 

 ber to February, when the mean direction is E. N. E. in the western part of the 

 ocean, probably owing to the heating of a part of S. America, towards which the 

 air is drawn from the ocean. (See also Map, Plate 6.) 



The more easterly direction of. the trades in the western part of the ocean is 

 well marked, especially as concerns the S. E. trade. It is probably due to the 

 rotation of the earth, which gives the winds more easting the further they advance. 



There is no doubt that the winds of the Atlantic which blow near the coasts 

 of America have traversed a great part of the ocean, and thus acquired more 

 easting. As to the winds which blow in the eastern part of the ocean, they do 

 not come from so fiir. The African continent rather attracts the winds than 

 otherwise. It has before been shown that from 5° N. to 20° S. southwesterly winds 

 blow the whole year on the ocean near the coast of Africa, as exhibited on Plate 7. 

 Thus the trade which blows further to the west cannot come from Africa. It 

 originates on the Atlantic Ocean itself, over the cold antarctic current flowing at 

 some distance from the African coast. 



