Lyttelton and of the harbour itself. Ripa Island, however—where the quarantine establishment is at present placed—is a very favourable site for a work to fulfil these objects, and here I propose that there should be constructed a battery by which you will observe the whole harbour will be well commanded. This work will be rendered perfectly secure against capture by assault, and will also be protected against being silenced by a body of men which an enemy might have succeeded in landing in the adjacent inlet, called Port Levy, and gaining possession for a time of the heights overlooking the harbour on the southern side. This last operation is one which, considering the precipitous character of the country, I do not conceive to be likely, but it is a contingency which, in the design of the work, should be provided against. The guns on Ripa Island, thus completely secure against being silenced or against capture, will absolutely deny the use of the harbour to an enemy, and will prevent his taking up a position therein with a view of effecting any hostile object. It would be desirable, however, to place some pieces of artillery on the North Shore, so as to bring a cross-fire to bear on an attacking vessel, and to command small bays on the southern side which are not seen into from Ripa Island. Torpedo-vessels will co-operate with the shore batteries, and will also prevent an enemy lying unmolested in Port Levy, Pigeon Bay, or Akaroa Harbour. A field-force of artillery and infantry, acting from Lyttelton upon the road from Lyttelton to Sumner, would both aid in the defence of the harbour, and effectually prevent any attempt to land at Sumner and advance therefrom to Christchurch. Dunedin and Port Chalmers. Dunedin, situated at the head of the estuary which forms the harbour of Otago (see Plate IV.), at about twelve miles distance from its entrance, is only divided from the sea by a low neck of land about a mile wide, which on the sea-side is called the Ocean Beach. Midway between the city and the entrance is Port Chalmers. During the last few years the water between Port Chalmers and the city has been considerably deepened, but Port Chalmers remains the anchorage for the largest ships. It has been determined to construct a training-wall at the entrance to the port, opposite Taiaroa Head, and ultimately another but shorter one, in continuation of that head, with a view of deepening the channel. These harbour works will not, however, affect the plan of defence. As observed by Major-General Scratchley, an enemy may either