1845.] Thirteenth Memoir on the Law of Storms in India. 719 



till 2.20' p. m. on this day when it became calm and shifted to the NW. 

 that is to say, the centre passed her (or she drifted across it ?) to the 

 eastward of her position at that time. 



We have not her position at noon this day, and I have therefore esti- 

 mated it only, by allowing her to have drifted bodily to leeward at the 

 rate of three miles per hour on a West, WNW. and NW. course, which 

 will give, with variation and a current of 2' per hour to the SW. a 

 course and distance of N. 85° W. 90 miles, which is the best estimation 

 we can make. I have not allowed her the full current which the Charles 

 Heddle experienced, because as I shall elsewhere shew, I do not at present* 

 think it probable, that the effect of the Storm Wave extends strongly to 

 any great distance from the centres, though the storm Currents are felt 

 all over the vortex.f The Arpenteur certainly did not partake of the 

 Charles Heddle' s storm wave to the SW. for her position on the 27th 

 is about what a vessel might have been drifted to by the mere effects 

 of the hurricane and storm Currents. 



For the log of the 27th February. — At noon the Charles Heddle, 

 though she had made one more turn round her circle since the 26th, 

 appears to have the fine weather commencing, i. e. at length to have 

 scudded out of the hurricane ; or it might have left her. She appears at 

 noon to have had the wind about EbN. which would give the centre bear- 

 ing NbW. from her, and I should consider, though the average of this 

 day gives but twenty-five miles, yet that by this time, Noon, she was at 

 a much greater distance from it, the weather now beginning so evidently 

 to be fine.. We shall thus not be far wrong, if we say that at noon the 

 centre bore NbW. forty-five miles from her ; this distance, forty-five 

 miles, being it will be seen, the average distance of the whole five 

 days, and it will be noted on the chart, that this still keeps her, as our 

 averages shew, within about twenty-five or thirty miles of the centre till 

 about six a. m. when she begins to increase her distance from it, so that 

 it is probably very close upon the truth. This position for the centre 

 will place the Arpenteur, which also had fine weather returning from 

 3 a. m., at sixty miles from the centre, with about a SWbS. wind, if she 

 still partook of the same hurricane. 



* I say at present, because it is not wholly impossible that this view may be modified. 

 At present all the facts we have, appear to tend to this supposition. 



f The reader will find the word storm wave, and storm current explained in the 

 Eighth Memoir, Jour. As. Society, Vol. XII. p. 398. 



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