METEOROLOGY AXD ALLIED SUBJECTS. 



291 



tlie east coast of the island towards tlie cyclone in tlie neighborhood of 

 Iceland. The following similar tables relate to the middle latitudes of 

 North America : 



stations. 



Prevailing 'winds. 



Summer. 



Winter. 



Saint Paul's Island, Alaska 



Southern Alaska 



Washington Territory , 



Oregon 



California 



Arizona 



New Mexico 



Utah 



Eastern Eocky Mountain slope . 



Florida 



Bahamas 



Alabama , 



Mississippi, Louisiana , 



SE. to SW. 

 SW. to flW. 

 SW. to NW. 



S. and W. 



SE. and S. 

 S. 



S. and W. 



SE. and S. 

 SE. and SW. 



E. and SE. 

 SE. 



SE. to SW. 



s. 



N.toE. 



E. and SE. 



SE. and SW. 



S. and SE. 



N. 



W. and NE. 



SW. and W. and N. 



N. and NW. 



NW.. N., and NE. 



N. and NE. 



NW. and N. 



N., NE., and W. 



As showing how little the trade winds control throughout the year, 

 we have but to study the mean annual wind direction with their re- 

 sultants ; thus even in the Northern Bahamas, where the ratio is most 

 nearly such as would belong to the trade wind, we find that the resultant 

 wind for the year is north 87° east, while at Florida Keys it is north- 

 76° east. {Z. 0. G. ilf., XIV., 1879, pp. 1 to 18.) 



Hann summarizes the results of observations by Kersten, Seward, 

 and others, in regard to the climate of Zanzibar. He says atmos 

 pheric currents in Zanzibar deserve a special consideration, since the 

 seasonal change in the winds is here the basis of all weather phenomena. 

 The northeast monsoon (that in 1864 began to be perceptible some 

 weeks after the passage of the sun southward through the equator, but 

 attained its full force after the middle of December, when the sun had 

 reached its extreme southern position) brings higher temperature, 

 lower pressure, and higher moisture. 



The opposite features characterize the southwest monsoon, which 

 commences shortly after the second passage of the sun through the zenith, 

 and at first is accompanied by calms, but from the end of March onward 

 foY three months continues almost uninterruptedly to blow as a fresh 

 breeze. In July and August, however, the southwest wind fails again 

 for some weeks, diminishing to a light breeze, and even occasionally for 

 a few hours shifts again to a weak northerly wind ; in October the 

 southwest again blows with less strength, interrupted by many calms, 

 which by November always get the upper hand, and by the end of the 

 month give way to the northeast monsoon. Thus the southwest mon- 

 soon prevails for seven months ; two months are changeable, namely, 

 March and November, and only three months from the middle of Decem- 

 ber to the middle of March belong to the northeast monsoon. {Z. 0. 0. 

 M., 1879, XIV, pp. 22 to 24.) 



