ELECTRIC CABLE COMMITTEE.

F.—No. 4.

23

Cable Route near Rotti. 14. If Koepang be adopted as an intermediate station it would probably be laid between Savu and Eotti, arriving at Koepang direct from the westward. Thence it would pass down Semao Strait, and leave Eotti Strait by its eastern entrance. If the cable be laid direct it will be a question for the projectors of the line whether they will lay it through Eotti Strait, or to the southward of Eotti. 15. Tho Islands Savu, Banjoar, and Hocky, are situated on a bank. The section (on G. H. 1., plan 1) shows Hocky, which is an upheaved coral reef, to rise from an inclined plane at the depth of 700 fathoms sand. I would, therefore, recommend the cable being laid outside Hocky in a depth exceeding 800 fathoms. The island is surrounded by a sea-bottom composed of coarse coral sand, coral debris, and corallines, which become finer in character as the distance from the island is increased. Direct line. 16. South of Sumba the cable should pursue the course indicated on plan 1 by the double red line. The single red line is perfectly direct, and four miles shorter, but impracticable on account of its close proximity to the island of Hocky. 17. It crosses the deepest water South of Sumbawa in 1,850 fathoms, but the slight deviation proposed reduces the depths 200 or 300 fathoms. The contours of the sea-bottom appear here to be remarkably regular, and to run nearly parallel to the general line of coast. 18. Tho charts show, near this locality, depths not obtained with 2,000 and 2,980 fathoms of line, but they are imaginary, and probably the results of circumstances which were unfavourable. There can be no question of the accuracy of the present soundings, all of which were taken from a boat; indeed the probability is in favour of their being always less than is indicated on the plan. 19. Baly Strait, through which the cable must be taken to sea, required almost a re-survey, on account of the difficulty experienced in ascertaining the ship's position —a matter of importance in laying the cable in the narrow, serpentine, deep water channel of the strait, where alone an oozo bottom can be found. The variation of the compass proved to have been the chief impediment, as it was subsequently observed to be a degree more easterly than shown on the charts. Some care will be necessary in following the proposed cable route out of the strait, and I should recommend that advantage be taken of the period of neap tides. The tides and currents are most complex and irregular, and not to be learned readily by a stranger. 20. This deep water channel is contracted to two miles width near the entrance of the strait, by rocky ground on either side, which may be seen by reference to plan No. 2. The Baly ledge on the East side appears to be an extension of the Baly shore ; it is of coral, and may have less water than shown on the chart, as it was not examined. The same remark may apply to the Java ledge, which is of rock, and is evidently a plateau extending from the shore, over which was found a uniform depth of 218 fathoms. Higher up the strait, the Prince of Orange coral bank divides tho channel into two, the northern of which is to be preferred, as the wider and more ■direct. Serpent Bank. 21. It will also be seen, by reference to plan No. 2, that the bed of the strait rises suddenly, forming a plateau having a slight incline and steep declivity. The character of the bottom is one highly injurious to the proper preservation of a cable (and appears to be of rock overlaid with sand, mud, gravel, corallines, and hard black angular stones, resembling lava), especially at the edge of the plateau. After several days' search one spot was found at which the bottom was of a less unfavourable nature ; and here, at 10 miles East of Mount Ikan, the proposed line has been drawn on the plan. Towards the entrance of Pampang Bay the ground is chiefly sand and mud, varied by a little coarse sand and stones. Pampang Bay. 22. The western shore of Pampang Bay has been selected for landing the shore end of the cable; the reasons for its selection being, that it is the only place protected from the heavy swell which the S.E. monsoon rolls into the strait, and that tho shore is soft mud, overlaid here and there by fine black sand, admirably adapted for the purpose, as also is its approach. The coast between Pampang and Banyu-Wangie, the present terminus of the electric telegraph, is, in addition to being thus exposed, exceedingly rocky, whilst the distance between the two places is only 14|- miles, or about 17 by the road, which is gained from Pampang Bay by a bridle-path along the shore. Pampang is a small Javanese or Malay village, and has the character of being very unhealthy, especially at the changes of the monsoons. 23. Plan No. 3 illustrates how the cable should bo laid. Starting from the creek South of the village, it is carried directly across tho wide mud-flat fronting the shore as far as low-water mark, which leads sufficiently wide of the usual anchorage of small craft off the village. Thence it crosses the bay diagonally, on a line marked by two white beacons, until the western extreme of Mount Ikan bears South, whence it advances westward in a long sweep across the " Serpent " Bank. The beacons should be large and conspicuous, to indicate where it would be illegal for a ship to anchor. 24. All the sand is black, and contains iron, which is also found in all specimens of the bottom in the vicinity of Baly and Lombock and Java. Specimens of the bottom. 25. A collection of specimens has been made from all depths, especially from tho " Serpent" Bank in Baly Strait. They will be retained on board till the " Serpent's " arrival in England. Chas. Bullock, Commander, E.N. Her Majesty's Ship, " Serpent," Point de Galle, 10th March, 1869.