POOTTOOR WELL. 



125 



establishment of the fact that it was impossible to affect the level 

 of the well or to check the curious rise and fall of its water. This 

 latter phenomenon has earned for it the title of the "Tidal Well of 

 Poottoor." 



I think I have now mentioned all the facts I am aware of, which 

 might assist any one in forming an opinion as to the cause of the 

 peculiarities of this well. These peculiarities are three in num- 

 ber. 



First in importance is the tide above mentioned. 



Secondly, the presence of salt water from a depth of between 45 

 and 50 feet to the bottom of the well, &c. 



Thirdly, its apparent inexhaustibility. The experiments just 

 completed were undertaken with reference to the two first conditions 

 only, the experiments of 1324 being considered conclusive as to 

 the third. 



Experiments. 



The first step taken was, by a careful section taken from the 

 low water mark on the southern to the low water mark on the 

 northern shore, to ascertain the relation that the level of the sur- 

 face water of the well bore to the tidal marks of the sea on both 

 shores. Levels were taken for a distance of 17 miles from Jaffna 

 on the south coast to Valvettytorre on the northern coast. 



The fact so established is, that the level of the fresh water in the 

 well coincides almost exactly with the low water level of the sea 

 on both coasts. 



The next experiment was conducted with a view of ascertaining 

 at what depths the fresh water ceased and salt water commenced, 

 and to procure specimens of the water at various depths to be sent 

 to England for analysis. An instrument with a closely fitting 

 valve was made for this purpose, so arranged that the valve could 

 be opened and closed again at any given depth. 



The first symptom of brackishness was found between 40 and 

 50 ft. down, and it appears certain that it is at this point that the 

 salt water enters. Specimens of the water at the surface, 45 ft., 95 ft., 

 145 ft. (the bottom) were procured and put into sealed bottles. 



