THEORY OF CYCLONES VON BEZOLD 365 



On the contrary, the existence of the cloud proves that in any such 

 case these descending motions, which in themselves are not improb- 

 able, cannot be very important since otherwise adiabatic compres- 

 sion must occur and thus cloud formation would be impossible. 



The matter is somewhat different in the case of large cyclones, for 

 there it is quite conceivable that in the beginning of these or in case 

 of their rapid development in the median strata of the atmosphere 

 (which may either be due to the general circulation or be a result 

 of local expansion of the air) , air may be drawn in as easily from above 

 as below. 



By simple modifications of the above-given figure we can also 

 obtain systems of critical and isobaric surfaces in which the down- 

 draft must extend down to the earth's surface so that a natural 

 explanation is found for the so-called "eye of the storm," as also 

 for the remarkable dryness observed in the interior of a cyclone, as, 

 for example, in the hurricane 15 of 1882, October 28, at Manila. 18 



The investigations which I have here carried out started with the 

 consideration of the centered whirl. Notwithstanding the limita- 

 tion to this very special case they seem sufficient to remove the 

 characterization of abnormal or inexplicable from the peculiar rela- 

 tions that Hann has shown to exist in cyclones with cold centers and 

 anticyclones with warm centers. 



Not the less are they appropriate to lead us back to a correct 

 appreciation of the views defended by Faye as to the descending 

 currents in the interior of cyclones and within certain limits pre- 

 pare the way for a reconciliation between this idea and that which 

 has become almost universal. 



15 Sprung: Lehrbuch, p. 24. 



16 Similar phenomena may also be reproduced in rotating liquids. In 

 these we can even develop whirls in which ascending movements occur in the 

 mantle but descending in the axis. See v. Bezold. Sitzb. Berlin Acad., 

 1887, pp. 261-277. 



