168 



THE MECHANICS OF THE E^SiRTH S ATMOSPHERE. 



I have also executed the farther complete coinputatiou for the first 



4 



case where c=-k', the results of this work are s'i^eu in Table 2. lu this 

 5 



computation the equations (29) and (30) were used for the determina- 

 tion of the velocities go and the deviations s of the direction of the wind 

 from the radial gradient. Furthermore, the difterences of pressure 

 {p—})-) with respect to that at the center, in the circles of radius r, were 

 computed according to equations (31), (32), (33) and (34). These latter 

 are, however, converted from the units ordinarily used in hydro- 

 dynamics into differences of barometric pressure {b — h„). This latter 



is easily done if we recall that for &=7G0 millimetres the ratio - is 



equal to the square of the Newtonian velocity of sound ; therefore we 

 have the proportion 



[h-K) 



im=-^{p-iKy, (279.9)-^ 



The gradients ;/ are in our present case the differences of barometric 

 pressure for a horizontal distance of 100 kilometres. 



Table II. 



From this table we see that the cyclone includes a broad storm 

 region from /• = 200 to r=500 kilometres, of which a portion is in the 

 inner region and another portion in the outer region. Uf course the 

 gradients are greatest in the inner region ; therefore there the isobars 

 are most crowded together. 



From those values of the constant c that are any way possible, it fol- 

 lows that the velocity of the ascending current of air is extraordinarily 

 small; for the present exami)le c* e(]uals 0.000090. If we assume that 

 the formula ic=cz holds good to an altitude of 1,000 metres, then tiie 

 vertical velocity would at that height lirst attain the value of about 0.1 

 metre per second. 



Hitherto the discussion has exclusively dealt with regions of ascend- 



k 



