132 THE WORLD. 



investigated the phenomena of the great storms which traverse 

 the Atlantic coast, they may .be traced to the N. E. of the West 

 India islands, and are from thence, drifted to the westward on a 

 track which inclines generally to the northward and eastward* 

 The rate of progression varies from 12 to 30 miles per hour, and 

 the storm whirls or blows from right to left, in a horizontal circuit, 

 on a vertical and some what inclined axis of rotation which is 

 carried forward by the storm. Mr. Espy has proposed a theory 

 which to us appears at variance with the facts derived from gen* 

 eral observation, and independent of any hypothesis. According 

 to this doctrine, it is alleged that during hurricanes, the wind, in- 

 stead of blowing in a circle, rushes directly from the exterior to- 

 wards the centre, to supply a vertical current under influence of 

 the suction, or vacuum power caused by the rarefaction and as- 

 cent of air, consequent from the extrication of the latent heat of 

 vapor during condensation. This theory has been ably defended 

 by Dr. Hare. The rotary theory of storms is now pretty generally 

 acknowledged, and has been advocated by Mr. Redfield, Sir 

 John Herschel, Lieut. Col. Reid, Prof. Dove of Prussia, and 

 Mr. Alex. Thorn. The latter gentleman has published a book 

 ttn the nature and course of storms, in which, he traces the ori- 

 gin, and describes the phenomena, of the great hurricanes annu- 

 ally occurring in the Indian ocean, showing them to be vast cir- 

 cuits of wind, revolving in a particular direction with unerring 

 regularity ; that they move from about latitude 10 S. by a south- 

 westerly track, curving towards the tropic. Their diurnal rate of 

 progression diminishes as they recede from the equator. These 

 hurricanes are formed by the westerly monsoons, and the S. E. 

 trade winds; the following diagram is extracted from Mr. Thorns' 

 work, and will illustrate the manner in which these storms are 

 generated. 



When the hurricanes are first noticed they are from 400 to 

 500 and even 600 miles in extent, or diameter, and consequently, 

 as the space between the monsoons and the trades is seldom 

 more than 100 miles, the outer portions of the circle must be in- 

 volved in the two winds for tht space of two hundred miles on 

 each side. Each wind therefore communicates a part, if not the 



