1842.] A Sixth Memoir on the Law of Storms in India. 651 



27th September. — 5 a. m. Wind E. by 3., Noon S. E. by E. again. 

 At 6, saw the Triton Sand-bank, bearing about E. S. E., distant 10 

 miles; 7, made sail. At 10, by the bearings, latitude 15° 50' N., longi- 

 tude 111° 12' N. Noon Bar. 29.53. Ther. 83°. p. m. fresh breeze from S. 

 E. and fine. At 1 30 p. m. Discovery Shoal from N. to E. A northerly 

 current of 47 miles for the last 24 hours. 



To this log is appended the following important note : " Mr. Wise, 

 " formerly an officer of the Castle Huntley, remarks, that when this 

 " tyfoon commenced, the ship was to the East of the Macclesfield 

 " Shoal, and drifted during it upwards of 300 miles* under bare poles, 

 f having sighted the westernmost of the Paracels before the gale 

 " terminated." 



There can be no doubt that this was a storm passing to the South 

 of the ship ; and as the gale veered from N. E. to S. E. b E., while the 

 drift of the ship was from noon the 25th to 10 a. m. on the 27th N. 

 67i° ^' 210 miles, this when projected gives the centre of the storm 

 a track of from S. 77° E. to N. 77° w -, which is probably not far 

 from the truth. The Barometer falling only to 29.00, though the 

 tyfoon was severe, shews that the distance of 70 miles from the cen- 

 tre which this projection allows when it was nearest to the ship, is not 

 excessive. 



The projection will also furnish us with an approximation to the 

 rate of travelling of the centre of this storm. The drift from noon 

 25th to 10 a. m. on the 27th, is as I have said 210 miles, and the 

 centre, (the wind being N. E.) at the first epoch, bore S. E. from the 

 ship, and at the latter S. W. by S. Assuming that at about noon on 

 the 26th the centre bore due South, (wind being between E. N. E. 

 at 10, and E. by S. at 1 p. m.) we have thus three lines of bearing for 

 it, and taking the distance of it to be as I have before stated, it will be 

 found that it must have travelled about 180 miles, or 7i miles per 

 hour in each of the 24 hours. 



The extraordinary drift is a phenomena of the highest importance 

 to navigation, and it is evidently analogous to those experienced on the 

 South Coast of China, both probably occasioned by the " storm wave." 



* Note. — So in MSS. The measured drift is 210 miles between Noon 25th and 

 10 a. m, 27th. Mr. Wise's calculation seems made from an earlier hour on the 25th. 



