Prof. Dove's Outlines of a general Theory of the Winds. 227 



usual manner during the day, and the whole quantity is the 

 same as the carbonic acid in the atmosphere, neither more 

 nor less. 

 August 9, 1837. J» D] 



XXVI. On the Influence of the Rotation of the Earth on the 

 Currents of its Atmosphere ; being Outlines of a general Theory 

 of the Winds. By Prof H. W. Dove of Berlin * 

 [With a Plate.] 

 "VTOT one of the philosophers who have attempted to give 

 -^ a theory of the winds, has gone beyond the discussion 

 of the regular phaenomena between the tropics ; for which, 

 indeed, they cannot be blamed, as it is right in a very compli- 

 cated investigation to examine the most simple case first. 

 But, on the other hand, it must seem strange that since 1685, 

 (in which year Halley published his theory of the trade-winds, 

 consequently for 150 years), not a step has been made to- 

 wards a general solution of the question. The purpose of this 

 treatise is to show, that the phaenomena of the trade-winds, 

 those of the monsoons, and the complicated relations of the 

 winds of the temperate and frigid zones are necessary and 

 simple consequences of the same fundamental physical causes. 



The velocity of rotation of the single points of the surface 

 of the earth is in proportion to the semidiameter of the parallel 

 circles under which they lie ; it therefore increases from the 

 poles, where it is zero, to the equator, where it is greatest. In 

 the state of rest the air partakes of the velocity of rotation of 

 the place over which it is. If, therefore, from the difference 

 of temperature, or from any other cause, it receives an impulse 

 to flow in a parallel circle, the rotation of the earth will not 

 have any influence upon it, because the points of the sur- 

 face at which the current of air arrives, have exactly the same 

 velocity of rotation as the points whence it has proceeded. 

 But if air is by any cause propelled from the pole towards the 

 equator, then it comes from places whose celerity of rotation 

 is small, to places at which it is greater. The air, consequently, 

 then turns with less celerity to the east than the places with 

 which it comes in contact; it therefore seems to flow in an op- 

 posite direction, viz. from east to west. The deviation of the 

 wind from its original direction will be the greater, the more 

 the velocity of rotation of the point of starting, by an equal 

 progressive motion, differs from the velocity of rotation of the 

 place at which the wind is observed, viz. the greater the dif- 

 ference of geographical latitude of both places. Hence fol- 

 lows: 



* From Pogscndorff's Annalen, vol. xxxvi. p. 321. 

 2G2 



