1849.] Eighteenth Memoir on the Law of Storms. 901 



distinct, as remarked by Capt. Shire in the China Sea, (Journ. Vol. 

 XVIII. p. 49.) 



4. Peculiar Lightning. — This is also noted in the log and remarks 

 of the Barham, pp. 835, 837, and corroborates what we before knew of 

 this peculiar Aurora Borealis or flashing kind of lightning. This appear- 

 ance is not mentioned by any of the other ships, and it is singular to 

 remark that while some vessels in the Cyclone had no lightning, or 

 but very little, others had very severe thunder and lightning. It would 

 appear that there may be certain zones or quarters of the Cyclone in 

 which alone the electrical discharges occur, so far we can at present 

 judge. Like many other matters, this requires to be better observed before 

 we affirm any thing positively on the subject. I have collected in 

 another section the evidence we have now obtained on this curious 

 point. 



Vibration of the Barometer. — This remarkable sign we find very 

 carefully noted in the log of the Barham ; and in that of the Sea Park, 

 that the Barometer and Simpiesometer were falling at the time the 

 daily rise should take place. 



So far then as relates to the precursory signs of these meteors, we 

 have collected here, from the observations in a single Cyclone, a great 

 number of them, quite sufficient indeed to warn the attentive mariner 

 of what may be at least passing near to him, if not approaching his 

 position, and thence to give him frequently much more time for his 

 preparations, — and time is often with him a question of masts or dis- 

 masting — or even of life and death ! 



Of Phenomena during the Cyclone. 



Dimensions of the Cyclone and its unequal extent in van and rear.* 

 I have already discussed at p. 897, the reasons which induce me to 

 believe that this was a distinct instance of a Cyclone settling down in 

 the middle of the Bay, perhaps after it had been raging in the China 

 Sea, and certainly after it had picked up hundreds of land birds and 

 thousands of insects from some land which it had passed over, and I 



* This word rear may sound more military than nautical to merchants, and even 

 to some naval-bred seamen of modern days ; but as we have the van, centre, and 

 rear of a fleet, we may with propriety use these words for the artificial divisions of 

 " our enemy," the Cyclone. 



6 A 



