STORMS, HURRICANES, AND TYPHOONS. 401 



equator — i. e., they first travel westwardly, inclining towards the 

 nearest pole ; they then recurve and travel eastwardly, still 

 inclining towards the pole ; and that such is their path in both 

 hemispheres, etc. 



786. The questions why these storms should recurve, and wh^^ 

 Puzzling questions, they should travel as they do, and why they should 

 turn with the hands of a watch in the southern, and against them 

 in the northern hemisphere, are still considered by many as puzzles, 

 though it is thought that their course to the westward in the 

 trade-wind region, and to the eastward in the counter-trades, 

 is caused by the general movement of the atmosphere, like the 

 whirls in an angry flood, which, though they revolve, yet they 

 are borne down stream with the currents as they do revolve. The 

 motion polarward is caused, the conjecture is, by the fact that the 

 equatorial edge of the storm has, in consequence of diurnal rota- 

 tion, a greater velocity than its polar edge. There seems, how- 

 ever, to be less difficulty with regard to their turning than with 

 regard to their course ; the former is now regarded as the resultant 

 of diurnal rotation and of those forces of translation which propel 

 the winds along the surface of our planet. This composition of 

 the forces of the revolving storm, and the resolution of them, are 

 precisely such (§ 215) as to produce opposite rotation on opposite 

 sides of the equator. 



787. Many of the phenomena connected with tliese storms still 

 Espy's theory, remain to be explained ; even the facts with regard 



to them are disputed by some. The late Professor Espy, after 

 having discussed for many years numerous observations that have 

 been made chiefly on shore, maintained that the wind does not 

 blow around the vortex or place of low barometer, but directly 

 towards it. He held that the place of low barometer, instead of 

 being a disc, is generally an oblong, in the shape of a long trough, 

 between two atmospherical waves ; that it is curved with its 

 convex side toward the east ; that it is sometimes nearly straight, 

 and generally of great length from north to south, reaching in 

 America, from the Gulf of Mexico to the great lakes and beyond, 

 and having but little breadth in proportion to its length ; that it 

 travels east, moving side foremost, requiring about two days to 

 go from the Mississippi to St. John's, Newfoundland ; that on 

 either side of it, but many miles distant, there is a ridge of high 

 barometer ; that the wind on either side of the line of low baro- 

 meter, in which there is Httle or no wind, blows tovv-p.rd it. etc., 



