224 On the Alpine Glacier, Iceberg, [No. 159. 



the velocity of wave transmission, and that the old idea of the power 

 of waves extending only a little way down in the sea is not true as 

 touching waves of translation, — the motion and power of which is 

 nearly as great at the bottom as at the top. 



He further demonstrates, that the motion of this wave does not fluc- 

 tuate, but is continuous and forward during the entire transit of its 

 length ; hence a complete transposition is the result of its movement : 

 and the wave of translation, he says, may be regarded as a mechani- 

 cal agent for the transmission of power as complete and perfect as the 

 lever or inclined plane. 



Reasoning from such data, Mr. Hopkins states, that currents of 25 

 and 30 miles an hour may be easily accounted for, if repetitions of 

 elevations from 160 to 200 feet be granted ; and with motive powers 

 producing a repetition of such waves he infers, from mathematical and 

 mechanical arguments, that there would be no difficulty in transport- 

 ing to great distances masses of rock of larger dimensions than any 

 boulders in the north of England. 



Mr. Hopkins has also shown by mathematical analysis, that the 

 overland march of glaciers over large and flat continents is a theory 

 founded on mechanical error, and involves conclusions irreconcilable 

 with the deductions of collateral branches of physical science. 



Such is a brief abstract, derived principally from the Geological So- 

 ciety's Proceedings of the theories which divide the geological world 

 at home regarding the boulder formation. General Briggs, perceiving 

 that India was silent, while Europe, part of Asia, and America in both 

 hemispheres, were contributing to the general stock of knowledge on 

 this head, applied to some of the local authorities in the East to lend 

 their aid in eliciting information, and among others to the Marquis of 

 Tweeddale and General Fraser, to whom I have already transmitted 

 some memoranda on the subject, at their request. 



On mature consideration, however, I am of opinion that the mode 

 I have adopted, of publishing an abstract of the theories on the 

 subject which agitate geologists, with a notice of the leading feature 

 of the principal alluvial deposits of Southern India as far as hitherto 

 known, followed by a short description of the characteristics of the 

 true boulder formation, by which it may be recognized when found in 

 Southern India, and a list of the chief points to which the observer's 

 attention should be directed in gaining useful information on this head, 



