179 



Journal of the Asiatic Society of Bengal for March 1837. — By the 

 Society. 



Scientific Memoirs, selected from the Transactions of Foreign 

 Academies of Science and Learned Societies, and from Fo- 

 reign Journals. Edited by Richard Taylor, F. S. A. &c. vol. i. 

 — By the Editor. 



AjSynopsis of Chronology from the era of Creation, according to 



^ ^. the Septuagint, to the year 1837. By William Cuninghame, 

 Esq. — By the Author. 



Monday, \st January 1838. 



Dr ABERCROMBIE, v. p. in the Chair. 

 The following Communication was read : 



On the Terrestrial Mechanism of the Tides. By John 

 Scott Russell, Esq. 



Under the title Terrestrial Mechanism of the Tides, the author 

 of this paper means to include the consideration of those caus^es 

 which regulate the propagation of the tides, so as to exclude en- 

 tirely the examination of the mechanism by which they are prima- 

 rily produced. The generation of the tidal elevation in the Pacific 

 or Atlantic Ocean is a question entirely of celestial mechanics. 

 But the tides, after having been generated by solar and lunar at- 

 traction in a manner that is found to be perfectly in accordance 

 with the varying intensities of these forces, do not subside at the 

 instant when these forces cease to act, but continue to exist during 

 a long period of time, reaching our shores three days after their 

 birth ; and have obeyed, during this long interval, laws perfectly 

 independent of the original influence by which they were produced, 

 and presented phenomena in direct opposition to it. They have 

 obeyed the laws of terrestrial hydrodynamics. The law of the 

 propagation of the tidal wave through the ocean and around our 

 shores, belongs therefore to terrestrial, not to celestial mechanics. 



Although our knowledge of the celestial mechanism of the tides 

 has recently attained a high degree of accuracy, our knowledge of 

 the terrestrial mechanism has been hitherto almost entirely conjec- 

 tural. In the former department, the system of Bernouilli, based 

 on the discoveries of Sir Isaac Newton, presents us with a theory 

 of the tides in close accordance with the phenomena. Laplace, in 



