1839.] on the 3d, 4th, and 5t/i of June, 1839. 641 



register, with the peculiar state of the atmosphere so well described in 

 the remarks of Captain Paterson, of the H. C. S. Amherst — and her 

 track from Akyab we must remember was almost in the direction of 

 the path of the hurricane till it overtook her at the Sand Heads — are 

 well worth considering. 



These are but vague theories, it will be said, but it will not be 

 forgotten that theories on a new subject, like torches in exploring dark 

 caverns often lead us to the passage we seek ; though not by the road we 

 expected. " We have only to be ready to lay them aside when they 

 have served our turn/'* and if I venture to introduce this one here 

 it is to point attention to the importance of obtaining electric observa- 

 tions if possible. 



The slow rate at which the vortex appears to have travelled also seems 

 to show, as before remarked, that it was, as it were, pent up between the 

 great stream of air blowing along the Arracan range and the Coroman- 

 del Hills. We see analogous instances to this in the small bays at the sides 

 of rivers, where while there is one part of the stream turning round the 

 shores of it and another flowing from point to point, we see the eddies 

 are from time to time found almost stationary about the middle of the 

 bay.t 



I wish to be understood here however as suggesting probable com- 

 parisons rather than advancing a theory. 



Col. Reid and Mr. Redfield give from ten to thirty miles per hour for 

 the rates at which the centres of their different vortices have probably 

 travelled onwards. If our centres are correctly laid down ; and I think 

 there is good evidence that at least those of the 4th and 5th are so; it 

 appears that from the 3rd to the 4th the Hurricane travelled onwards 

 only about 100 miles, or say 4-16 per hour, and from the 4th to the 5th 

 about 70 or 83 miles per hour. This again is conformable to what we 

 observe in the bends of a stream where the eddies seem to start from 

 some point, and move onwards with more rapidity in the first part of 

 their course than latterly. Should future experience confirm this 

 instance of the slow progress of our Hurricane, it will become an im- 

 portant element in any calculation to be made by the seaman for 

 avoiding their violence. 



* Sir John Herschel. 



f In the rivers of India banks are often formed at these points, which ending by 

 choking the stream as the river becomes lower, changes its channel in succeeding years. 



