402 



HYDROGRAPHY. 



HURRICANE STORMS. 



The fifth postulate which I have laid down, viz., that currents of 

 air are influenced and disturbed by electricity, will, I think, be readily 

 admitted. 



The sudden changes in the atmospheric currents during thunder- 

 storms, water-spouts, and whirlwinds, have been perceived by every 

 one; and none fail to notice that they usually rise against opposing 

 currents of air, which they overcome and entirely divert from their 

 course. 



The ordinary storms we consider as the result of the accumulation 

 of heat and vapor over an extended area. The duration and violence 

 depend upon the difference of temperature between the heated area 

 and the denser air by which it is surrounded. They may have 

 greater or less extent. Observation proves their route to be in the 

 order of progression of the currents of air, as heretofore explained. 

 The hurricane storm is similar, but with the addition of intense 

 electrical action, which produces the local whirl. In other words, the 

 true hurricane storm is to be regarded as an electrical meteor. These 

 we intend to describe. 



Although electricity has not been admitted as the great agent 

 which causes the hurricane storms, that carry destruction and leave 

 devastation in their track, yet it is well known to be one of the 

 accompaniments, and its effect afterwards is always seen. It will be 

 my endeavor to show that it is the cause of their origin, and, com- 

 bined with heat and dynamical forces, sufficient to explain all the 

 phenomena which are witnessed in their local as well as progressive 

 motion. 



My purpose is first to treat of the general character of these 

 meteors, endeavor to explain the cause, give their direction, and the 

 areas to which they are confined. 



In the first place, these storms, in various parts of the earth's 

 surface, arise from the same' causes, and have the same signs and 

 appearances. From the observations of navigators, as well as 

 observers on land, we learn that their characteristics in both hemi- 



