22 THE CLIMATOLOGY OF THE UNITED STATES. 



instead of passing around to the south, southwest and 

 west, as in the case of a storm passing down the St. Law- 

 rence valley to the north of us. The majority of storms 

 after leaving our coast travel to the northeastward, across 

 the Atlantic and pass north of England. When a storm 

 first develops it is of small area ; but as it progresses 

 from day to day its diameter increases and in high lati- 

 tudes it disappears from this very fact ; for when the di- 

 ameter of the centre becomes so great that the ascending 

 air does not overflow, but cools and sinks back into the 

 centre again, the storm dies out. 



Tornadoes are very destructive storms of small area 

 and tremendous energy which frequent the centre of the 

 country, being most destructive in Kansas, Illinois, Mis- 

 souri and neighboring states. The South Atlantic states 

 have also been visited by very disastrous ones, especially 

 in February, 1884, when a great many people were killed 

 and wounded and thousands of dollars' worth of property 

 destroyed within a few hours. Until within the last few 

 years very little has been known about the nature of these 

 storms or the laws governing them ; and it is only within 

 the last two years that the Signal Service has attempted 

 to give any daily indications of their probable occurrence 

 for different localities. Their sudden development, nar- 

 row paths and short courses, together with their destruc- 

 tive force, have prevented very accurate observations until 

 lately. What appears to be a thunder storm rises in the 

 west and in the midst a funnel-shaped cloud appears sus- 

 pended above the earth, moving up and down and swaying 

 from side to side. The clouds above appear in greatest com- 

 motion, while an indescribable roaring is heard in the. air. 

 The storm travels like others, generally in a northeasterly 

 direction, sometimes veering toward the north at the rate 

 of about thirty miles an hour. They are liable to occur 



