i8 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 'JO 



average wind velocity in the northern part of the region (Chan- 

 nel-New York) is comparatively great and considerably less in 

 the southeast part between Portugal and the Azores. The distri- 

 bution of air pressure and wind is approximately the same in 

 March and February but in March it appears that the wind is on 

 the whole somewhat more westerly and somewhat weaker in the 

 region we have investigated than in February. 



Figure io. The mean surface temperature (W), air temperature (L), and 

 the difference between these (W-L) for the 2° fields along the shipping course 

 Channel to New York in the eleven-year period 1900 to 191 1. The full drawn 

 lines are for the first decade group (February 2 to March 4), the dotted lines 

 for the last decade group (March 15 to April 13). 



The average temperature of the air in February is given in the 

 usual manner in figure 9. The isotherms for the air and the sur- 

 face of the water follow in their principal features the same course, 

 although in our investigated region the water on the whole is 

 warmer than the air, particularly in February. 



