1849.] Seventeenth Memoir on the Laio of Storms. 27 



the westward of Grand Ladrone, where the ship remained three days refitting, the 

 current setting W. S. W. the whole time, about two knots per hour. 



It would appear that this Cyclone was a very partial one, for as I am 

 informed by Captain Powell, ships at a short distance to the northward 

 of the Hyderee had topgallant sails set. Nevertheless it is worth noting 

 as being perhaps analogous to, if not of the same kind, as the Tornado 

 Cyclones off the Coast of Ceylon, and near Cape Negrais,* which are 

 peculiarly dangerous on account of the little warning they afford, and 

 their tendency to appear in fine weather, when ships are least on their 

 guard against them. We have recently had an instance of their occur- 

 rence at the Sandheads, occasioning the loss of the Barque Nussur, with 

 all hands on board. 



The average shift being from East to S. E. would give a track to the 

 W. N. W. from the E. S. E., but as we must make some allowance for 

 the ship's drift to the southward during the first part of the Cyclone, 

 I have allowed it one to the E. b. N. \ N. which will not be far from 

 a correct estimation. 



Track J. 



H. M. S. Ringdove, Straits of Formosa, Sept. 1846. 



I have marked this as a Cyclone, H. M. S. Ringdove having had a 

 severe gale on the 15th and 16th Sept. (force of the wind being marked as 

 high as 1 and 11.12, being hurricane force) from the North, which af- 

 ter an hour's calm again returned at S. W., but in this last half both its 

 duration and force were far less than in the first part, in which it was 

 blowing for 27 hours from N. E. to North, with a force of from 8 to 11, 

 falling a dead calm from force 10, whereas in the latter half of the 

 Cyclone it was blowing only from force 4 to 8, and this for about 12 

 hours at most. This is partly accounted for by her bearing up and 

 running to the North and N. E., which was directly out of the vortex, 

 and partly no doubt from the influence of the coast of China, close to 

 which she was. Nevertheless, these apparent anomalies or peculiarities, 

 should be faithfully noted to aid us in future research. 



Abridged Log II. M. S. Ringdove. 



At Noon 14th Sept. 1846. Lat. 24° 0' N.; Long. 119° 45' ; wind N. E. 

 force (5) ; veering to North at 7 p. m. and from that time to midnight varying 



* Sailor's Horn Book, p. 38, Journal Asiatic Society, Vols. IX. and XIV. 



E 2 



