964 



Memoir on Indian Earthquakes. By Lieutenant R, Baird Smith, Ben- 

 gal Engineers. 



Part III. Analysis of the Phenomena of Indian Earthquakes, as exhibited 

 in the two preceding parts of this Memoir. 



All available facts connected with earthquakes in India and its 

 frontier countries having now been given, it remains that the infer- 

 ences authorised by these facts shall be duly exhibited. To this li- 

 mited object I propose confining myself, it forming no part of my design 

 to offer any general views of the theory of Earthquake shocks, but 

 simply to illustrate their nature and causes so far as the materials 

 collected in this country admit. The combination of these materials 

 with others gleaned from different earthquake tracts, will doubtless 

 lead to interesting general results, but such a work must be left to 

 some one who commands better opportunities and greater leisure than 

 I at present have. 



The facts already given naturally subdivide themselves into two 

 main classes; first, those illustrating the various phenomena; and 

 second, those indicating the causes of earthquake shocks. To the 

 former, attention will in the first instance be directed. 



1. Characteristics of the Shock in Earthquakes. 



The sensations experienced during earthquakes, as described by ob- 

 servers, are of three kinds. 



a. A sensation of undulatory movements illustrated by comparison 

 with the motion of a ship at sea, the wavelike progress of a snake in 

 water, or the rocking of a cradle. 



By far the larger portion of shocks in India give origin to sensa- 

 tions of this character. It would be tedious, and it is unnecessary to de- 

 tail a large number of examples, but reference may be made to the 

 great shock of the 19th February, 1842, as peculiarly illustrative of the 

 point under notice. At Jellalabad it is said, " the earth swung to and 

 fro like the rocking of a cradle," and at Peshawar, " the earth rocked 

 like an infant's cradle, or like a ship at sea. 



6. A sensation of sharp, severe concussion, as though the observer 

 were struck heavily from beneath or behind ; as examples of this se- 



