238 WEATHER AND CLIMATE 



accuracy. If a cyclone were central over the lower Mis- 

 sissippi valley with an anti-cyclone to the west of it, we 

 should expect that the southerly and southeasterly winds 

 and rains to the east and southeast of the Mississippi would 

 gradually change to fair weather and westerly winds with 

 increasing cold, as the cyclonic area was replaced by the 

 anti-cyclonic. 



The rate at which the change would take place would 

 depend upon the rapidity of the movements of the two 

 areas of high and low pressure, and the order of change in 

 the direction of the winds would depend, for any place, 

 upon the directions taken by the centers of these areas. 

 The direction of movement and the rapidity of movement 

 of the cyclonic areas are, therefore, two of the chief factors 

 which enter into the prediction of the weather. There is 

 usually an increase in the intensity of the storm as the 

 Atlantic coast is approached. 



Climate. The average succession of weather changes 

 throughout the year, considered for a long period of years, 

 constitutes the climate. Thus, if the average temperature 

 of a place throughout the year has for a long period been 

 found to be high, and the rainfall large and uniformly 

 distributed, the place is said to have a hot and humid climate. 

 The climate is a generalized statement of the weather. 

 Two places may have the same average temperature through- 

 out the year without having the same climate, as in one the 

 temperature may be quite uniform and in the other very high 

 at one season and very low at another. Many factors enter 

 into the making up of a comprehensive statement of climate. 



Effect of Mountains on Climate. All over the world 

 where people have the money and the leisure they are 



