Prof. Dove's Outlines of a general Theory of the Winds. 361 



The greater this is, the greater also becomes the difference of 

 the rapidity of rotation of the places at which it arrives one 

 after the other. 



The wind springs back more frequently between S. and W. 

 on the northern hemisphere than between N. and E. ; and 

 the more frequently also, the more violently it rages. 



If the southern current has prevailed for some time exclu- 

 sively at one place, and if it is finally expelled by a colder, 

 and therefore denser polar current, this takes place with 

 greater violence. Violent storms therefore pass from SW. 

 through W. into NW. First, then, when the wind becomes 

 N. and NE., its violence decreases. The extremes of mete- 

 orological instruments do not coincide with N. and S., but 

 rather with NE. or E. and SW. or W. Then, as for instance, 

 the NE. is properly a north which comes from more northern 

 regions than the N. it must be colder, drier, and heavier than 

 the latter, &c. The individual character of single periods is 

 occasioned by these currents. Its occurrence in the southern 

 currents (an excess of SW. and W. winds) brings mild winter 

 and coldsummer, with frequent and considerable precipitations; 

 its occurrence in the northern current, on the contrary, causes 

 a cold winter and hot summer with great dryness. In the 

 first case the warm equatorial air, which rushes towards the 

 pole, advances into higher and higher degrees of latitude, its 

 capacity for vapour continually diminishing; and thus it loses 

 its vapour by continually repeated precipitations. In the second 

 case, however, the cold air of the quietly flowing northern 

 current comes gradually into lower degrees of latitude ; its 

 capacity for vapour gradually rises, and during the continu- 

 ance of this current, the sky remains serene as with a NE. 

 trade wind. 



If the two currents meet one another, not at a greater or 

 smaller angle, but lie exactly opposite each other at their 

 meeting, they concuss one another often for a long time. If 

 the currents possess no considerable intensity, there originates 

 at the place of their meeting, especially in autumn and winter, 

 a thick fog, which frequently disappears all at once, and re- 

 appears, accordingly as the place of observation is situated on 

 the northern current, or on the boundaries of the southern one. 

 If the southern current is of considerable violence, it flows 

 above the opposing northern current, and prevails in the upper 

 regions of the atmosphere, while in the lower regions there 

 is a calm. The barometrical minimum here observed will 

 find its explanation in the dreadful storms which prevail in 

 southern districts. Barometrical maxima arise from a jostling 

 of the northern current with the southern opposing one. 



Third Series. Vol. 1 1. No. (58. Oct. 1837. 3 A 



