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10. View of Thursday Island, taken from on board "Coal Hulk," by Dr. Finsch (of Bremen). 11. Plan of Normanby Sound, 1875.

12. Report of Commander Heath, R.N., on Thursday Island, 1875.

13. Report on Queensland Pearl Fisheries, by H. M. Chester, Police Magistrate, 1879. 14. Commodore Wilson's Chart.

Appendix No. 4.

THURSDAY ISLAND.

APPENDIX (B).

Note on the Naval and Military Defence of the Australian Colonics, including New Zealand and

Tasmania.

[Not yet completed.]

No. 106.

War Office Memorandum on the Defence of Thursday Island and Normanby Sound.

NORMANBY SOUND is the channel inclosed between the Islands of Goode, Ham- mond, Thursday, Prince of Wales, and Friday, which form part of a group of small islands situated towards the south side of Torres Straits. It is about 4 miles long, 1 wide, and affords fair anchoring-ground for vessels drawing 22 feet of water; the safest being nearly centrally situated between the four last-mentioned islands.

There are several approaches to the anchorage; that from the west, between Goode and Friday Islands, being the deepest and widest, and the only one suitable for vessels of the above-mentioned draught.

The Ellis Channel, between Thursday and Horn Islands, is navigable by vessels drawing 16 feet, but is difficult and much obstructed by shoals and reefs.

The Aplin Pass, between Thursday and Hammond Islands, is navigable by vessels of about the same size as the last-mentioned; but it also is difficult of navigation, and in places less than 200 yards wide.

The other three channels, viz., those between the Islands of Goode and Hammond, Friday, and Prince of Wales, Prince of Wales and Horn, are said to be so full of obstruc- tions as to be nothing better than boat channels. The tides through these various channels are strong and most irregular, neaps often rising higher and running stronger than springs.

The islands themselves, which are stated to be composed of porphyry, syenite, and silicious schists, are described for the most part as barren and hilly, with intervening wooded valleys, their coast-lines being more or less skirted with the coral formations which abound throughout the whole of the Torres Straits. Water is abundant on the surface in March, and it is thought could, by digging, be found the year round.

Vivien Point, the south-western extremity of Thursday Island, has been selected as the site for the future Settlement, some few buildings of which have already been constructed.

Little information can be gathered either as to the population of these islands or their local trade. The former appears to consist chiefly of roving native savages, and the latter to be due to a sinall pearl fishery; but it is quite evident that the anchorage alone gives any importance to the place.

As this anchorage lies close to and between the two main channels in these dangerous straits, through which passes the trade not only between Singapore and the castern Colonies of Australia, but also between the Indian and South Pacific Oceans, its strategical importance will be at once recognized.

To secure the anchorage from bombardment, it would be necessary to erect works to command the various approaches. In the case of the main channel between Goode and Friday Islands, such works should be near the entrance to the Sound. This channel being deep and free from obstruction, the swift tide and rocky bottom being unfavourable for the use of electro-contact submarine mines, and there being a clear run ahead, a vessel might steam past works so placed at considerable speed. The best chance of making them respected would be to give them a powerful and comparatively numerous armament.

The works might be on Friday Island, near its east and west extremities; or one might be in the latter situation and another on Goode Island. All these sites being isolated, the batteries would have to be made self-defensible

A work on the east end of Thursday Island would be necessary to hold the Aplin Pass and Ellis Channel, and possibly batteries for medium guns might be required on Prince of Wales Island, to deny the channels of approach on either side of it. It is evident that such a system of defence, in addition to being very costly and demanding a numerous garrison, would be so scattered and disjointed as to render combined and mutually supporting action a practical impossibility. This being so, it is submitted that the topography of Normanby Sound is such as to unfit it for a harbour in which vessels might lie in security and refit.

To deny its use as a coaling and provision depôt it will suffice to occupy some convenient position overlooking the anchorage, and fairly commanding the several channels of approach.

The most eligible site for such a purpose appears to be the hill above Kate Point, the southernmost extremity of Hammond Island. The disadvantage, however, of dividing the

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