682 



WINDS OF THE GLOBE. 



S. W. in summer. In Behring Strait southerly winds are also more numerous in 

 summer, while the Arctic Ocean northward of it has northerly winds at the same 

 season. 



In the last two stations lying near Hudson's Bay, a monsoon influence is exhibited 

 in the S. winds of winter. Hudson's Bay does not freeze entirely, and thus the 

 wind will blow towards it from the land. (See Maps, Plates 5, 6, and 14.) 



TEMPERATE ZONE OF AMERICA WEST OF THE ROCKT MOUNTAINS. 



On the coast of Alaska and further south in Washington Territory, the winds 

 have a monsoon character. The cause of this is the difference of temperature and 

 consequently of pressure on land and sea, producing a current of air from the land 

 in winter, and from the sea in summer. 



It is necessary to remember that the warm current of the Kuro-Sivo, the Gulf 

 Stream of the Pacific, passes, in its return to the south, near to this coast, and there 

 must be a diminished pressure over the region, at least in the colder part of the 

 year. The interior of the continent is very cold at that time, and therefore the 

 pressure of the air must be high there. 



In the summer there is a narrow cold current passing between the coast and 

 the Kuro-Sivo, while at the same time the interior of the continent has a great 

 excess of temperature over the coast, and, as in other dry and warm continental 

 areas, the pressure must be low. 



There is no country of the world where the temperature of the summer increases 

 so much as we go from the coast to the interior as on the Pacific slope of America, 

 from Alaska to Lower California. The summer isotherm of 59° passes near San 

 Francisco on the coast of California, and is supposed to reach the polar circle on 

 the Yukon River, in the interior of Alaska, a diff'erence of 28° in latitude. Fort 

 Miller, in the interior of California, has a summer temperature of 85°. 5, and Mon- 

 terey, on the coast, and in the same latitude, but 59.0 ; diff'erence 26.5 F. The 

 percentage of winds in Alaska and Washington is given below, and, with the help 

 of the maps, PI. 5 and 6, will serve to illustrate the winds of this region. Plate 

 14 gives the atmospheric pressure. 





Summer. 



Winter. 1 



a 



& 



- 



w 





^ 



^ 





a" 

 11 



22 



12 

 21 

 12 

 16 

 5 



6 

 4 

 16 

 18 

 16 

 9 

 17 



w 



12 

 12 



24 

 13 



25 

 11 

 18 



a 



9 

 12 

 17 

 24 

 17 

 24 

 25 



25 



14 

 10 

 15 

 10 

 12 

 5 



16 

 9 

 7 

 3 

 7 

 13 

 15 



14 



'I 

 0.3 

 5 

 8 

 3 



8 

 16 

 7 

 6 

 7 

 6 

 12 



Isl. of St. Paul,' Alaska, Beh- 

 ring Sea 



Iluluk, Aleutian Islands' 



Fort Wrangel 



Fort Tongass 



Sitka 



N. W. Washington . . . 

 S. W. Washington . . . 



7 

 5 

 6 

 5 

 4 

 6 



6 

 4 

 4 

 4 

 6 

 4 



6 

 9 

 2 

 9 

 3 

 



17 

 8 



25 

 8 



13 

 9 



19 

 13 

 45 



13 

 21 

 3 



21 

 25 



8 

 25 

 31 



16 



6 

 17 



8 

 17 

 17 

 28 



9 

 18 



6 

 18 



4 

 33 



' From Report of Chief Signal Officer, 1874. 



