112 Mr. T. D. La Touch e & Mr. Elson— Ow the Barisdl Guns. [March, 



sounds may be heard at any time during the day or night, and always 

 appear to come from the direction of the Brahmaputra, which skirts the 

 western end of the hills. They are heard at considerable distances from 

 the river banks, at least 30 miles in a direct line, over hills and valleys 

 covered with dense jungle ; and I hardly think that the fall of a bank 

 of even 30 ft. high could be heard at that distance. They seemed to be 

 most distinct near the village of Mohendraganj at the S. W. corner of 

 the hill area, close to an old bed of the river, but I did not see any 

 banks fall in during the few days I was there. I have heard them only 

 during the cold weather, but I believe they are heard at other times. 

 They can hardly then be caused by heavy surf during the S. W. mon- 

 soon, unless different causes could give rise to the same phenomenon. 



With regard to the bamboo theory, I have often seen and heard dry 

 bamboo jangle on fire in March and April, when the Garos burn their 

 jhiims, and though the bursting of the bamboos makes a great noise, it 

 is more like the rattle of musketry than the firing of heavy guns and 

 cannot be heard at any great distance, especially when hills intervene. 



It has occurred to me that a ])ossible cause of these sounds may be 

 the daily increase and decrease in depth of the water in the rivers of 

 the delta, caused by the tides. It may be that the rising of the waters 

 places the superficial strata in a state of strain, which is relieved when 

 the tide falls, and the consequent earth movements, though slight, Tnay 

 give rise to these sounds. This is, however, merely a conjecture, and I 

 do not feel inclined to lay much stress upon it until the subject has been 

 more thorougbly investigated. 



Mr. Elson remarked, with reference to what had been read about 

 the Barisal Guns having been heard at Tumluk on the Riipnarain 

 river, that it was just possible the explosive noises were due to the 

 falling in of portions of the high right river bank in Hooghly Bigbt, 

 a spot peculiarly fitted for the production of the phenomenon, situated 

 immediately at the mouth of that river, at its junction with the Hooghly, 

 The rolling action of the joined streams of the two rivers had so cut 

 away and undermined the bank, that the original raised embankment had 

 in some places succumbed, the bank itself being ' up and down ' like a 

 wall, with some ten or twelve fathoms alongside it at low water : and 

 Mr. Elson had himself often witnessed the crashing sound of the falling 

 in of large masses of earth when anchored near this spot ; generally at 

 about low water, when the falling tide left the bank without its sup- 

 porting lateral pressure, the bank gave way and fell. And he believed 

 the sound of these landslips might be conveyed for many miles along 

 a dense water medium : and very possibly distance so altered sound 

 waves through this medium that the noise would not be beard as a loud 



