220 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 51 



This case is that of cyclones that move nearly parallel to the ali- 

 mentary stratum and where the alimentary air describes a very 

 small angle in order to reach the interior region. 



In the northern hemisphere the wind deviates to the right and 

 turns around the center aeainst the sun and consequently the cy- 



T, 



r 



r* 



FIG. 35 



FIG. 36 



clone moves around the alimentary stratum with the sun (see 

 fig- 35)- I n tne southern hemisphere the inverse phenomenon 

 occurs (see fig. 37). 



When the cyclone passes any point, the temperature increases at 

 first, but during the passage of the center it lowers (see figs. 36 

 and 38). 



Since in general the mean or normal isotherms do not deviate 



much from the direction of the parallels of latitude of the terrestrial 



globe, we must expect the cyclone to be formed on the south of the 



supplementary air and on the north of the alimentary air and 



also that it move in general from west to east. 



r 

 Second example. Assume ~ = 10 and u> = 200 . By equation 



(9) we shall find 



a 



W 



U 9 



- 40° 

 = 0.35 



45° 



0.25 



50° 

 0.41 



55° 

 0.03 



In this case the cyclone also moves nearly parallel to the 

 alimentary stratum, but the alimentary air describes about half 

 a revolution around the cyclone before reaching its interior region. 



