906 Eighteenth Memoir on the Law of Storms. [Sept. 



Off the Sandheads we have the log of the Camperdown, which ship, 

 even on the 10th, found a strong S. W. current of 3 miles per hour 

 running, with several of the Pilots' reports, though this current is so 

 well known to them at the approach of a Cyclone that they rarely no- 

 tice it, and as already stated on a trial in the Pilot's Court, which arose 

 out of circumstances occurring at the onset of this Cyclone, it was sworn 

 to by several experienced witnesses, of long standing, that the Westerly 

 current was in their judgment running from 3 to 4 knots per hour, 

 which is independent of the tide. So that if we take 1\ knots per 

 hour it will not be an excessive average for this current in the parallel 

 of the outer Light Vessel, or 21° 4' N. 



On the coast we have only the log of the Sir Robert Seppings, mark- 

 ing distinctly the Southerly set on the 11th of 2 miles per hour, but 

 it is not necessary to repeat here what I have elsewhere said of the 

 sweep of the current round the shores of Balasore Bay, and past Point 

 Palmiras. 



Barometer as measuring the distance of the Centre. 



Having the places of the centre of the Cyclone pretty correctly 

 marked for the 12th and 13th, I at first anticipated that this Cyclone 

 might afford us some tests to know if the rule laid down by me for 

 ascertaining the distance of the centre of the Cyclone by the rate of 

 fall of the Barometer per hour, would give correct results with one 

 which, as to extent, we call a small, and as to rate of motion a slow- 

 moving Cyclone. Unfortunately, so far as our present knowledge 

 extends, we have no rule within 150 miles of the centre ; and our 

 Cyclone does not fairly in any case reach to this extent of semi-diameter 

 except towards the land where the Barometrical indications seem always 

 affected by it for some distance, if the land be not very low. Hence from 



McLeod, one of the oldest commanders in the trade between Calcutta and England, 

 who in a Cyclone in October, 1832, (the London's Cyclone) ran up from about 

 15£ North, on the meridian of about 89£ East, on the Eastern verge of a Cyclone 

 with " a terrific hurricane" about South ; and when preparing to heave to at a safe 

 distance, as they supposed, from the Sandheads, found themselves in 8§ fathoms on 

 the tails of the Sunderbund reefs, but fortunately beat off. With every allowance 

 Captain McLeod finds that they certainly overran the log about 70 miles in 30 

 hours ! 



