1888.] Lt.-Col. J. Watcrliouse— On the Barisil Guns. 109 



therefore, that in some cases the sounds may be caused in this way, 

 though it is certain that they are not the sole cause, as shown by Capt. 

 Stewart's and Mr, Beveridge's statements that the sounds are heard in 

 places where no marriages ever take place and where there are no river 

 banks to fall in, and though the latter further states that his informants 

 at Kiikri Mukri told him that the sounds were quite unconnected with 

 the surf, the bore, or the tide, still these sound-producing agencies 

 existed on or near the spot and might have been instrumental in causing 

 the sounds, though the islanders may not have recognized it. 



As regards the fourth theory, that the sounds are due to subterra- 

 nean or subaqueous volcanic or seismic agencies, there is again no direct 

 evidence, but the current opinion that such is the case and the fact 

 recorded by Capt. Stewart of the sounds being like the explosion of a 

 distant torpedo, and always coming from the same direction of the 

 ' Swash of no-Ground,' when he heard them at Barisal, Kukri Mukri, 

 and other places in tlie Sundarbans, seem to point to some submarine 

 source. Mr. Beveridge also suggests their connection with the ' Swash 

 of no- Ground ' and the statements he i-eceived from natives regarding 

 the sounds being heard at Kiikri Mukri from the south-west, or direction 

 of Ceylon, agree with Capt. Stewart's observations. 



Capt. Stewart had an idea that the ' Swash ' was the crater of an 

 extinct volcano or submarine volcano and that subterraneous explosions 

 found vent and sound through it, which were heard inland during the 

 south-west monsoon. In the description of the ' Swash ' by Commander 

 Carpenter, R. N., of the Marine Sarvey, (Journal, A. S. B., Part II, 1885), 

 there is no allusion to any such volcanic character, but the formation of 

 the depression is shown to be caused by the convergence towards this 

 region of all the channels through the shoals formed off the mouths of all 

 the rivers of the Delta. The result of this tendency of the ebbing w^ater 

 is a number of whirls and eddies in that locality, the position of 

 the ' Swash ' being central with regard to the Deltaic mouths. This 

 constant agitation of the sea hereabouts prevents the mud settling here 

 during the ebb-tides, as it does on the banks on either side, which have 

 thus never been able to meet, and consequently the depth still remains 

 considerable. It would be most important to have further observations 

 as to the state of the sea during the monsoon over this depression, and 

 whether the contending currents cause such disturbance as would pro- 

 duce explosive sounds loud enough to be heard miles inland. 



Mr. Rainey has also suggested that the sounds may be of volcanic 

 or subterraneous origin, perhaps the upheaval of land as small islands 

 on the sea-face of the Delta or Sundarbans. He further notes that the 

 sounds travel from the direction of the active volcanic train runnino^ 



