1845.] Thirteenth Memoir on the Law of Storms in India. 



731 



and I allow for it the same variation, 1| point, as in Fig. III. the } 

 of a point more allowed during the last two days in the log making, as 

 before shewn, no difference worth noting. 



Table of the distance run with each wind. 



Hours. 



8 

 4 

 4 

 10 

 7 

 4 

 6 



10 

 11 

 7 

 8 

 7 

 9 



10 

 8 

 7 

 There are farther considerations arising out of 

 are much puzzled when we consider a vortex of air simply as whirling 

 round and without any progressive motion, to say whether there would 

 be a centrifugal or a centripetal tendency ? or a mere circular one, 

 throughout ? or even centrifugal at the circumference and centripetal 

 towards the centre ? 



The laws of physics would certainly indicate a centrifugal force, and 

 we usually suppose then an attraction to counterbalance this ; or again, the 

 mind reverts to the apparently well observed and attested accounts of 

 water spouts and whirlwinds, which all seem to lean to the fact of these 

 small vortices, at least, having rather a centripetal than a centrifugal 

 force ; that is, a particle of air or dust in the neighbourhood would be 

 drawn farther and farther inwards. Our present result is evidently to 

 shew this sort of incurving, and the diameter of the storm was a de- 

 creasing one ! 





Winds 





per Log. 



12 



North, 



13 



NNE. 



14 



NE. 



15 



NNE. 



16 



East, 



1 



ESE. 



2 



SE. 



3 



SSE. 



4 



South, 



5 



ssw. 



6 



sw. 



7 



wsw. 



8 



West, 



9 



WNW. 



10 



NW. 



11 



NNW. 



Corrected 



Distance run with 



for Var. 



that wind. 



NbW^W. 



85 



NjE. 



40 



NNE^E. 



43 



NEfE. 



111 



EbNJN. 



87 



E}S. 



57 



SEbE^E. 



65 



SEJS. 



94 



SbEJE. 



109 



SJWi 



77 



SSW£W. 



89 



SWiW. 



75 



WbS|S. 



100 



W|N. 



101 



NWbW|W. . 



88 



NW^N. 



71 



arising out of 



these results. We 



