DESCRIPTION OF MAPS AND DIAGRAMS. 751 



PLATE 5. 



Mean Direction in the Summer (June, July, August) between 80° N. Lat. and 56° S. Lat. 



This map shows the mean direction of the wind for the time in which the Northern Hemisphere is 

 highly heated, while the southern has its winter. Very prevailing sea-winds (S. W., S., S. E.) along 

 all the southern and eastern coast of Asia (the summer monsoon) are the principal features of the 

 season. In Australia, especially on the northern coast, land-winds prevail. They are S. E. in the 

 latter region. In other parts of the globe the difference between the direction of the wind in 

 summer and that for the year is smaller. Yet, in the United States, there is a monsoon region 

 north of the Gulf of Mexico, between the Rocky Mountains and the Mississippi. Southerly winds 

 from the gulf are largely prevailing there. In Northern Africa northerly winds prevail to a 

 larger extent than in the mean of the year. In the Atlantic the belt of the N. E. trade-winds has 

 the most northerly position in the year, while north of it there are prevailing N. and N. W. winds to 

 and beyond 40° N. lat. In Western Asia W. and N. W. winds prevail, this being a flow of air 

 towards the barometric depression in N. W. India. In Southern Russia we see westerly winds at this 

 season, the air flowing towards Central Asia. 



PLATE 6. 



Mean Direction in the Winter (December, January, February) between 80° N. Lat. and 



56° S. Lat. 



At this season the direction of the wind is nearly opposite to that observed in June, July and 

 August in the monsoon region of Asia. N. B. winds prevail in Southern India and the Indo- 

 Chinese Peninsula, N. and N. W. in the interior of India, and in China, Japan, and the Russian 

 Amoor Provinces. The N. E. monsoon crosses the equator, appearing as a N. W. wind on the 

 heated continent of Australia. In North America, Texas and the States to the north of it have 

 prevailing N. and N. W. winds — a direction nearly opposite to that of summer. The S. W. winds 

 which prevail the whole year in the temperate latitudes of the Northern Atlantic have now reached 

 the maximum of their frequency and strength, blowing also in a great part of Europe. Southern 

 Russia has prevailing east winds in winter. In Western Asia the westerly winds are not so largely 

 prevailing as in summer. The trade-wind belt of the Northern Atlantic and Northern Pacific 

 Oceans has receded to the southward. 



PLATE 1. 



Direction op the Wind in the Four Seasons between 80° N. Lat. and 56° S. Lat. 



The general arrangement of this table is the same as for Plate 4. It will be noticed that generally 

 the direction of the wind in spring is nearer to that of summer, and that of autumn to winter. This 

 is especially the case in monsoon regions. In Northern Europe and the eastern part of the Atlantic 

 Ocean the proportion of northerly winds is greatest in spring, giving, sometimes, a mean direction 

 N. of W., while the other seasons have a mean direction S. W. or W. In other places the larger 

 proportion of north winds has influence only in so far as to lessen the ratio of resultant, which is yet 

 S. of W. In Southern Russia and Asia Minor the autumn has the largest proportion of N. E. winds, 

 especially the months of September and October. Many places there have a mean direction nearly 

 E. N. E. in autumn, while it is somewhat S. of B. in winter and W. N. W. in summer. 



