H. W. Dove on the Law of Storms. 367 



which travelled from Brest to Cap Lindenaes in Norway. The 

 rotation in this whirlwind was in the direction S.E. N.W., 

 consequently on the S.E. side of the storm, that is to 

 say, in France, Holland, Germany, Italy, Denmark, and 

 Prussia the weather-vane veered from S.E. to S.W. and W. 

 through south ; on the contrary, towards the Atlantic coast of 

 North America the direction was N.E. At the same time I 

 observed in this memoir (p. 599.), that the greater number of 

 hurricanes in the southern hemisphere, which I had examined, 

 are whirlwinds rotating in the opposite direction. 



Three years later, Mr. Redfield of New York, arrived at 

 the same result by independent observations, as appears from 

 his memoir, entitled " Remarks on the prevailing Storms of 

 the Atlantic Coast of the North American States." (Silliman's 

 Amer. Journ. of Sc., 1831. Avril.) In a later memoir, how- 

 ever, on the gales and hurricanes of the western Atlantic (ib. 

 vol. xxxi.), Mr. Redfield has added a new and weighty fact 

 to those already accumulated by me. From the storms, the 

 course of which the American philosopher has there dis- 

 cussed and delineated by a chart, it follows, that the hurri- 

 canes taking their rise within the tropics, so long as they are 

 confined between these limits, retain unaltered their original 

 direction from S.E. to N.W. ; so soon, however, as they reach 

 the temperate zones, they suddenly bend round almost at a 

 right angle, and then travel from S.W. to N.E. Finally, 

 Lieut. -Colonel Reid, in his valuable treatise " On the Law of 

 Storms," published in 1838, confirms by new examples the 

 results already obtained, and especially calls attention to the 

 fact, that by this change in the direction of its course the 

 whirlwind spreads itself out continually from the centre more 

 and more. 



So long ago as the year 1735, Hadley proposed to solve 

 the problem of the trade-winds, upon the principle, that air 

 moving from the equator to the poles gradually acquires a 

 westerly, and on the contrary air moving from the poles to 

 the equator an easterly direction. A simple modification, or 

 rather extension of this theory, gives a key to all the compli- 

 cated phaenomena of the variable and apparently so irregular 

 motions of the wind observed in our own and other extra-tro- 

 pical latitudes. It is only necessary to take into considera- 

 tion the two currents contending for and alternately obtaining 

 the upper hand, in order to see that the origin of the current, 

 which Hadley treated as fixed for a given place, is in fact 

 variable ; wherefrom it follows, that the direction of the varie 

 ought to be not stationary, but changeable, according to a law 

 which I have named the law of rotation. From the same 



