252 Seventeenth Memoir on the Law of Storms. [March, 



led, they pointed out that the tendency of the road-way, even should it 

 stand, would be to sink in the middle — which any one who visits the 

 bridge and views it from the river will see is the case : and also that 

 the bridge would not stand, unless the middle link of the chain were 

 considerably strengthened. This last has had a double verification ; 

 first in the lamentable fall of the structure ; and, secondly, in its subse- 

 quent permanence since being reconstructed with the double central link 

 which it now has. 



These formulae were printed, I think, in 1846, (but without any ex- 

 planation of the manner in which they were to be used,)* as an Ap- 

 pendix to an important Report on the causes of the failure of the 

 Balee Khal Bridge, and the method of its re-construction, in the Trans- 

 actions of the Royal Engineers. No direct reference was made to the 

 formulae in the Report itself : they were added probably for future use. 



These then must be, I conceive, the formulae which Major Goodwyn 

 has in his mind in the passage I have quoted from his article of Octo- 

 ber last. But my Memoir has no connexion with them whatever : 

 nor have I ever put in print any deductions from the formulae till 

 induced to do so in the present communication. 



Calcutta, March 28th, 1849. 



A Seventeenth Memoir on the Law of Storms hi India, being Storms 

 of the China Seas from 1842 to 1847, and some of the Northern 

 Pacific Ocean, from 1797. By Henry Piddington, President of 

 Marine Courts of Enquiry, Calcutta. 



[Concluded from page 45.] 



Track S. 



Rob Roy's Manila Tyfoon of 13th Nov. 1847. 



The Rob Roy, which vessel was dismasted on the 18th November in 

 the Cyclone laid down in the proceding section, met with another 



* An explanation was subsequently sent to the Publisher of the Transactions 

 to supply this deficiency as soon as I was aware that the formulae had been made 

 public. 



