xiv 



JOURNAL R. A. S. (CEYLON). 



Vol. HI. 



and as it is very difficult to conceive in what way the sounds are 

 made under water, it would be well to have the subject more minutely 

 inquired into. 



I find the following in the Journal of the Samarang. I greatly doubt if 

 it be the same variety of fish that 1 have noticed that are referred to : — 



"Dr. Adams, the surgeon and naturalist of the expedition, says: — 

 ' While on board the brig Ariel, then lying off the month of the river of 

 Borneo, I had the good fortune to hear that solemn acquatic concert of 

 the far-famed organ fish, or drum — a species of Pogonias. These singular 

 fishes produce a loud monotonous singing sound, which rises and falls, 

 sometimes dies away, or assumes a very low drumming character ; and 

 the noise appeared to proceed mysteriously from the bottom of the vessel. 

 This strange submarine chorus of fishes continued to amuse us for about 

 a quarter of an hour, when the music, if so it may be called, suddenly 

 ceased, probably on the dispersion of the band of performers.'" 



Sir Emerson Tennent notices the fact of all the wells along shore which 

 keep their water during the dry season, being below high-water mark, and 

 that to a small extent they rise and fall with the tides ; and he assumes 

 that they owe their water to the sea, which loses its saline matter by 

 percolation. Nothing, surely, is more utterly opposed to the first principles 

 of Physics than the doctrine, thao salt held in chemical solution by 

 water should be capable of being separated from it by the mechanical 

 process of filtration. The phenomenon of tides in wells of moderate depth 

 dug near the sea, is of universal occurrence all along the Malabar Coast, 

 where the matter dug through is porous. It does not obtain in Avells 

 dug through trap. I have observed it hundreds of times at Bombay, 

 and have often had occasion to describe it, The explanation is easy. 

 The surface of the ground where the well is dug being always six or 

 eight feet above high and twenty to twenty-six feet above low water, 

 and being extremely spongy and porous down to where it conies in 

 contact with the rock, or the blue-clay bed which commonly lies over 

 the rock, it gets charged full of water during the rains. The superior 

 length of column enables this to expel the sea water, a proceeding which 

 must have been completed shortly after the emergence of the land from 

 the sea ; while the interestices in the porous soil are so minute as to 

 prevent the two mingling. As the saltest sea water has only a specific 

 gravity of L050, the fresh water ponded back from it requires only to 

 be proportionally higher in level to create an equilibrium. With a 

 greater head than this, it will push the wall of salt water before it, and 

 How off. Of all this I have seen abundant examples at Bombay. It 

 would occupy too much of your space to describe them. After six or 

 eight months of rainless weather, when the discharge from the soil 

 becomes feeble, the wells all become more or less brackish, and the 

 apparent tide increases. 



