406 



HYDROGRAPHY. 



attention has been given to the barometrical pressure. This is an 

 effect, not a cause, of the storm ; and in future, I trust that the tem- 

 perature, or thermometrical observations, may claim the attention of 

 those who have the misfortune to encounter them. I am well satis- 

 fied that it is a far better guide than the barometer, — and by noting 

 the standing, rising, or falling of the temperature of the air and water, 

 ample time will be allowed to prepare for these hurricanes. In every 

 case where I have found the observations of the thermometer recorded, 

 they show the clearest indications of the approach of a tempest ; and 

 by avoiding the line of the greatest heat, you may escape the discharges 

 of electricity and the whirlwinds caused by them. 



The part of the great Ocean where these meteors occur, lies between 

 the parallels of 10° and 30° north and south of the Equator. They 

 only take place in the North Atlantic, between America, Europe, and 

 Africa, and are first developed near to and about the longitude of 50° 

 west, to the eastward of the Leeward Islands, whence they sweep 

 along towards the coast of America, in a west and northwest direction, 

 as far as the longitude of 75° west, recurving to the northeast in the 

 latitude of 35°, and cease in about the longitude of 60° west, near the 

 45th parallel north. 



In the North Pacific, they begin near the Marianne Islands, in the 

 longitude of 140° east; from thence they extend to the coast of China, 

 in 100° east, turning to the northeast along the east coast of Japan. 

 In a few cases, they have been known to sweep across the Burmah 

 peninsula to Hindostan, where they are dissipated; others are con- 

 fined to the Bay of Bengal, from the Andaman Islands to the coast of 

 Coromandel. None of" these appear to recurve. Their course is pro- 

 bably short, and, coming in contact with the land, they are soon dis- 

 persed. 



In the Indian Ocean, they originate near the 90th degree of east 

 longitude; thence they pursue a course to the southwest to 40° east, 

 in the latitude of 27° south, where they recurve to the southward and 

 eastward. 



In the South Pacific, their limits seem to be between 140° west and 

 165° east. Their extent in latitude is over 25 degrees. Those that 

 have been experienced in the Southern Pacific recurve, but in what 

 direction the observations have not yet been sufficiently numerous to 

 establish. 



In examining the route which these meteors take, it will be found 



