1883.] Genl. J. T. WdWiQV—EartTi^uahe ofSlsl Dec, 1881. Gl 



alarmed him so much that he stopped the clock and did not restart it for 

 some hours, when there was less agitation of the sea-surface ; he then found 

 by the diagram that the earthquake waves were still existing and were 

 following one another with great regularity ; and they continued to do so 

 for about twenty-five hours after the first shock of the earthquake was felt, 

 when they died away. The diagrams at all the other tidal stations, for 

 the same day, were then examined, and evidence of a succession of ocean- 

 waves caused by the irreat earth- wave was unmistakeable at all the stations 

 on the west coast of the Bay and at Dublat station — at the south end of 

 Saugor Island — as well as at Port Blair. There was evidence of slight 

 disturbance at Diamond Harbour, 38 miles up the Hooghly beyond Saugor 

 Island J but there appeared to have been no disturbance whatever either of 

 river-surface at Rangoon and Moulmein, or of ocean-surface at Amherst, 

 and these are the only points on or near the east coast of the Bay at which 

 tidal registrations were being taken. 



Diagrams of the disturbed tidal curves — reduced from the original 

 records — are here given to indicate what actually took place at each spot, 

 and at the same moment of time ; for the latter purpose, all the hour lines 

 of the diagrams have reference to local mean time at Port Blair. The 

 curves from midnight of the 30th December up to the time when the sea- 

 waves began to reach each station — which falls between 8 A. m. at Port 

 Blair and 1 p. M. at Dublat, and possibly was as late as 3 p. M. at Diamond 

 Harbour — are normal in every instance ; and thus by comparing them 

 with the curves for the remainder of the twenty-four hours, the influence 

 of the earthquake in disturbing the normal tides is readily seen. For Port 

 Blair and Negapatam the normal curves are drawn below the actual curves ; 

 at the former place the diagram was torn by the pencil, and the record is 

 not continuous ; at Negapatam the curve from midnight up to the com- 

 mencement of the sea- waves is vibratory, and not firm, as at all the other 



stations ; but there the curves are normally 

 vibratory, probably because the piping, con- 

 necting the well of the gauge with the sea, 

 ends in shallow water and has not been 

 carried out far enough into the sea. The 

 longitudes of the several tidal stations west 

 of Port Blair, in time, are given in the 

 margin. 



Both the officers in charge of the tidal operations, first Major Hill 

 and afterwards Major Rogers, have taken much pains to ascertain all the 

 facts of the primary ' Great earth- wave' and the subsequent 'Sea- waves.' 

 It so happened that, at the time of the occurrence of the earth- wave, Major 

 Rogers was measuring angles with one of the great theodolites of this 



• H. 



M. 



Diamond Harbour . 



.. 



18 



Dublat 



.. 



20 



False Point 



.. 



24 



Vizagapatam ... . 



.. 



38 



Madras 



.. 



50 



Negapatam , 



.. 



52 



Paumben 



.. 



54 



