354 Prof. Dove's Outlines of a general Tlieory of the Winch, 



other in it, at one of which it is coldest, and at which the ba- 

 rometer stands highest ; at the other warmest, and at which the 

 barometer stands lowest. The barometric and thermal wind- 

 means decrease uninterruptedly from the maximum of the pres- 

 sure to its minimum, as also from the maximum of heat to its 

 minimum. The first point lies near to NE., the other near to 

 SW. If we now proceed from SW. through W. to NE., 

 the mean conditions of the thermometer decrease, while the 

 mean conditions of the barometer increase; if we go further 

 from NE. through E. to SW., the mean conditions of the 

 thermometer increase, while those of the barometer decrease. 



That which shows itself in the thermal and barometric wind- 

 means must also appear in the transitions of the same into one 

 another, i. e. in the mean thermal and barometric variations, 

 and indeed as well on the supposition of a changeable velocity 

 of rotation as of one which always remains the same (Poggen- 

 dorff's Annalen, vol. xxxi. p. 473). Since however the ela- 

 sticity of the aqueous vapour, with respect to its distribution in 

 the wind-compass, is closely related to the thermal, and the 

 pressure of the dry air to the barometrical, wind-compass ; 

 it follows, that the changes of the pressure of dry air and of 

 the barometer are exactly in inverse proportion to the changes 

 of the temperature of the air and of the elasticity of the aqueous 

 vapour contained in it. If we now suppose as the necessary 

 consequence of the former theoretical observations, that the 

 NW. acts the same part in the southern hemisphere as the 

 SW. in the northern, that a SE. there represents a NE. 

 here, we shall have the following result : 



A. Mean Variations of the Meteorological Instruments. 



Northern Hemisphere. Southern Hemisphere. 



1. The barometer falls by 1. The barometer falls with 

 E., SE. and south winds, E., NE. and north winds, 

 passes with SW. from falling passes with NW. from falling 

 into rising, rises with W., into rising, rises with W., 

 NW. and north winds, and SW. and south winds, and 

 passes with NE. from rising passes with SE. from rising 

 into falling. into falling. 



2. The thermometer rises 2. The thermometer rises 

 with E., SE. and south winds, with E., NE. and north winds, 

 passes with SW. from rising passes with NW. from rising 

 into falling, falls with W., into falling, falls with W., 

 NW. and north winds, and SW. and south winds, and 

 passes with NE. from falling passes with SE. from falling 

 into rising. into rising. 



