Dove on the Law of Storms. 325 



to serve as materials, formed by Mr. Redfield with the greatest 

 care, has further received a highly important augmentation, by 

 the magnificent work which the present Governor of the Ber- 

 mudas, Lieut. Colonel Reid, has published on the subject.* Col. 

 Reid has arrived at precisely the same result as Mr. Redfield, 

 and I know by written communications, that both these gen- 

 tlemen have done so quite independently of my earlier researches. 

 But Redfield and Reid, besides placing on a wider basis the rota- 

 tory movement which takes place in opposite senses in the two 

 hemispheres, have added further some very material observa- 

 tions, whose empirical establishment is entirely their own ; these 

 I shall now attempt to connect theoretically with the rotation 

 movement. 



In my first researches on the subject of the winds, I had refer- 

 red both the law of rotation and the rotatory movement of storms 

 to the mutual action of two currents of air, each tending to press 

 aside the other; but a more close investigation of the phenom- 

 ena has taught me to regard the law of rotation as resting on 

 more general conditions, and as being a simple and necessary 

 consequence of the rotation of the earth. The principle of Had- 

 ley's theory of the trade winds thus generalized, explained fully 

 all the rules which had been found for the non-periodic variations 

 of the meteorological instruments in the northern hemisphere, 

 and permitted the prediction of rules for the southern hemisphere ; 

 but it did not explain the rotatory movement of storms, and con- 

 sequently when I published my Meteor ologische Untersuchun- 

 gen, Berlin, 1837, which were made to embrace all that I had 

 previously written on the subject, I was obliged to retain the ear- 

 lier theoretical representation, since that which had been thus 

 empirically deduced had been fully confirmed, but without its 

 connexion with the principle of the general theory being shown. 

 The object of the present memoir is to supply this deficiency. 

 From the researches of Redfield and Reid we have the following 

 facts : — 



1. Storms which originate within the tropics preserve the first 

 direction of their path almost unaltered, until they enter either 



* An attempt to develop the law of storms by means of facts arranged according 

 to place and time, and hence to point out a cause for the variable winds, with a 

 view to practical use in navigation ; illustrated by charts and wood cuts. Lon- 

 don, 1833. 



