720 Thirteenth Memoir on the Law of Storms in India. [No. 166. 



There is however one anomaly here, which we must note. In this 

 twenty-four hours, as I have above remarked, the Charles Heddle clearly 

 scudded round the last of her circles, between Noon 26th and 5 a. m. 

 27th, and at the same time, that is, between Noon 26th and 3 a. m. 27th 

 the Arpenteur, at an average distance of thirty miles from her, also drifted 

 round a circle, having the winds it is said " all round the compass." 

 Now this evidently could not be the same vortex, and we must therefore 

 suppose that, as has been so often shewn before, the storm here divided, 

 which may have been the prelude to its breaking up ? I have therefore 

 marked two centres and two circles for the 26th and 27th, and my 

 readers will judge for themselves of the probability of their truth. It is 

 possible however, as the Arpenteur 's log is but very loosely written, that 

 there may have been only a series of varying streams, not enough to be 

 evidence of a true circle. 



We have no data for tracing the storm farther to the Westward, 

 and 1 shall now advert to its rates of motion as shewn by our centre, 

 and their relation to the Charles Heddle's spirals. The rates as shewn 

 by the projection on the chart then, are, 



Miles. 



22nd to 



23rd 



70 



23rd to 



24th 



100 



24th to 



25th 



115 



25th to 



26th 



89 



26th to 



27th 



85 



5) 459 



Per day 92 Miles. 



Per hour 3.8 



The Log of the " Charles Heddle," separately considered. 

 See Plate II. 



So many interesting questions must arise in the mind of every seaman 

 and of every scientific man, though not a seaman, in examining this log 

 and the diagrams which I have given in Plate II, that I have thought 

 it proper to devote a separate section to their consideration. They 

 would almost indeed afford materials for a separate Memoir. 



And first let me say, that, writing alike for the seaman and landsman, 

 I shall endeavour to make myself quite clearly understood by the latter, 

 and may thus at times appear prolix, or ostentatious of professional 



