904 Fourth Memoir on the Law of Storms in India. [No. 1 1 9. 



of the Barometer was experienced, and the storm was raging in its 

 greatest fury ; but it does not appear to me, that the winds from noon 

 of the 22nd, the time it was at W by S. to the following midnight, and 

 to noon of the 23rd, when it was a steady SW. tyfoon, allow us to 

 assign any other track. We may either suppose that the storm was only 

 forming on the 21st, or that the track curved away to the Eastward 

 to account for this possible anomaly in the distance from the centres. 

 It is certain a storm must begin somewhere, and I presume it here to have 

 done so on the same line as that on which we find we can track it 

 as a completely developed hurricane. 



Again ; if we attempt also to extend the circles of this storm at this 

 time, noon 22nd, to the London Thetis, we shall find that it would 

 give a SSE. wind, instead of a steady NNW. one, with every ap- 

 pearance of a storm and this storm really setting in a few hours 

 after, with exactly the changes of wind which should, by the theory, 

 occur. I may perhaps be thought prolix in this explanation of my 

 reasons for laying them down as two separate storms ; but I have 

 thought it very essential to our object, which is both to register the 

 facts, and to draw useful conclusions from them, to shew carefully 

 upon what grounds any thing is supposed to be proved which we 

 assume or lay down. 



At midnight 22nd-23rd, we find that the London Thetis has a 

 violent gale WNW. with terrific squalls and Barometer still falling. The 

 WNW. wind would place the centre bearing NNE. from her, and 

 allowing for her drift from noon, when she so prudently hove to, the 

 centre at this time may be about where we have placed it. The 

 Calcutta Thetis has the wind at this time at SW. a tremendous gale 

 also, which of course makes the centre of her storm bearing NW. 

 from her as I have placed it, and it will be observed that the 

 same discrepancy would exist, as before if we attempt to extend the 

 circle of the one ship's storm to the place of the other ; shewing I think 

 to demonstration, (for the places of both ships are perfectly well as- 

 certained,) that there must then have been the two storms which I have 

 laid down. 



There is a very remarkable fall of the Calcutta Thetis' Barometer ; viz. 

 29.40 to 28.80, or more than half an inch in the two hours preceding 

 this epoch (midnight of 23rd) and we find that at 2 a. m. on the 21st 



