It is remarkable that in the little island of Ramisseram, one of the chain which connects Adam's Bridge with the Indian continent, fresh water is found freely on sinking for it in the sand.

But this is not the case in the adjacent island of Manaar, which participates in the geologic character of the interior of Ceylon.

The fresh water in the Laccadive wells always fluctuates with the rise and fall of the tides.

In some rare instances, as on the little island of Bitra, which is the smallest inhabited spot in the group, the water, though abundant, is brackish, but this is susceptible of an explanation quite consistent with the experiments of Mr.Witt, which require that the process of percolation shall be continued "during _long_ periods and through _great masses of porous strata_;" Darwin equally concedes that to keep the rain fresh when banked in, as he assumes, by the sea, the mass of madrepore must be "sufficiently thick to prevent mechanical admixture; and where the land consists of loose blocks of coral with open interstices, the water, if a well be dug, is brackish." Conditions analogous to all these particularised, present themselves at Jaffna, and seem to indicate that the extent to which fresh water is found there, is directly connected with percolation from the sea.

The quantity of rain which annually falls is less than in England, being but thirty inches; whilst the average heat is highest in Ceylon, and the evaporation great in proportion.