190 THE MECHANICS OF THE EARTH's ATMOSPHERE. 



depends ouly on the geographical latitude (aud not also on the longi- 

 tude), then the motion of the air can only consist in vertical and me- 

 ridional currents, and which (corresponding to the above given compo- 

 nent velocities Ui, v^, u'l) consist of one lower current toward the equatt»r 

 and of one upper current toward the poles. The distribution of pres- 

 sure y()-\-v\ existing in connection with this furnishes (by means of th& 

 equation (4), page lS2of the previous nieaioir)the anticipated result that 

 on the surface of the earth the pressure increases from the equator to- 

 ward the pole, while at a medium altitude the differences of pressure 

 disappear, but that finally, at greater altitudes, the pressure is greatest 

 at the equator and least at the poles. 



Since as above remarked, the actual distribution of pressure in no- 

 wise agrees with the above, it must be concluded that the influence of 

 the term n+^i on the pressure can only be slight. 



From the previous developments it results that the term v., disappears 

 under the assumption of a uniform distribution of temperature symmet- 

 rical with the earth's axis, so that as was already indicated in the first 

 memoir, v^ will be the most important term. 



III. 



In the computation of this quantity Kj the system of equations pre- 

 viously given is to be used, namely : 



.Jy-i ^u ^11 ^u ^^ 

 ^x M' i)y ?^ 



.-,^^1 M' ?^' Jv 



(^ \ + U\ + V\- + IV — = — 2f M2 



?!/ ^v ^y ^z 



i)z ^x Jy i)z 



Since according to the accordant opinion of meteorologists, as alsO' 

 according to my previous deductions, it is very probable that the inten- 

 sity of the rotatory currents of the atmosphere materially exceeds that 

 of the meridional currents, therefore I have only introduced into the 

 further computation the rotation currents, whose components are des- 

 ignated by W2 au^l I'z- 



Since we have to do with a movement of rotation about the axis of ^ 

 therefore we can put 



"2 = — ,1'Z/, '•-' = + I.r, 1^2=0, 



and these values can also be used for u, v, aud ?o, in the above-given 

 system of equations. 



The relative angular velocity x is to be deduced from the expression 

 for the easterly component (see equation (9), page 183). This is a func- 



