Page:Madras Journal of Literature and Science, series 1, volume 6 (1837).djvu/139

1837.] Our preparations as regards boats are now nearly complete, to the full extent we will be able to man. We have three rafts and two weighing boats, and expect a small dhoney with two double catamarans from Jaffna, which will require two reliefs, of twenty-four men each, which is about the number available for duty. According to the rate at which we are now progressing, it will take about three or four months (100 or 120 working days), to deepen the channel three or four feet, according to the thickness of the upper strata of rock, which it is proposed entirely to remove, and give a general breadth of forty yards, besides removing a difficult bend in the centre of the channel.

The rock is very easy to work, and on an average one pound of powder breaks two tons, which we have no difficulty in weighing and removing to a distance on the reef. The divers fix the strings to the stones, which are hoisted up and lashed to the sides of the boats, the smaller only being taken on board. The vessel is then hauled off to a distance, and the stones cut away; the largest stone we have yet had occasion to remove has been about 3600-lbs., and took ten minutes to hoist and secure.

I have restricted the present plan to a breadth of forty yards, being nearly what it has at present.

Before more is undertaken, it will be necessary to ascertain what can be done to give a greater depth of water over the horse-shoe bank, which extends from this island to the main land, through which there is said to be only two channels, having ten feet water at the highest tides. The difficulty of passing this is little considered by the native commanders, as the risk is inconsiderable, and the inconvenience only extends to the delay of partly unloading the vessel. There are few crafts drawing more than ten feet frequent this passage, as the inner channel is said to have but twelve feet. I cannot satisfactorily account for the formation of the bar. The quantity of sand carried through is very trifling, and I imagine could not extend so far into the gulf of Manar, when the strength of the currents evidently sets on the east and west shores, where the present passages are found. It is just possible that this may be the ruins of the dam, when carried away by some great storm, a fact still recorded. In this case, not being subject to fluctuation, or any increase from a constant moving body, if once cut through by dredgers, or other means, it would always remain open, the current increasing with the depth of the water, and the bank being composed of coarse sand with fragments of coral and large gravel, totally differing from the small sand on the coasts, would not be subject to fill up. This is rendered probable by our experience in the small channel, no sand having lodged in the part lately excavated.

3d. Wind very strong with a high sea; no holes could be bored