NORTHERN AND SOUTHERN HEMISPHERES. -27 



when an atmospheric tide is raised by attraction, the 

 force which raises the tide tends to prevent atmo- 

 spheric pressure down wards ; so that the increase in 

 the depth of the atmosphere will not cause an equi- 

 valent rise in the height of the barometer. But, in 

 the case of such atmospheric tides as result from vis 

 inertiaa, we must obviously expect to find that the 

 pressure of the current, by which the tide is raised, will 

 cause a rise of the barometer more or less equivalent 

 to the height of the tide raised by the force of vis 

 inertia3. 



This being the case, and if the earth's position and 

 movements be determined by gravitation, then we 

 must expect that the action of these tidal forces will 

 be marked by the barometer showing less atmo- 

 spheric pressure on those parts of the earth's surface 

 which may be turned in the direction in which it 

 may be moving than on the opposite parts of the 

 surface. And, in fact, Captain Maury, in the dia- 

 gram of the winds at the end of his c Physical Geo- 

 graphy of the Sea,' marks the atmospheric pressure 

 at 28-93 about the Antarctic circle, and at 2 9 -7 6 about 

 the Arctic circle. This difference of pressure being 

 obviously such as, according to our theory, we should 

 expect if the solar system be moving in the direc- 

 tion of the south pole. 



But also ; for the same reasons which cause a 

 greater pressure in the northern than in the southern 

 hemisphere in case of the earth being in motion 



