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604 the chain of outlying forts (K K, &c.), which are posted from four to four and a half miles in front of the lines at Gosport, (2º) the inner line of works (J J, &c.) lying about two miles in front of the lines, and which are to be connected by regular lines, and (3º) the old Gosport lines themselves, which, though utterly inefficient as a protection against bombardment, would be nevertheless of use in repelling an attempt at capture. The distances between the forts which are to compose the outermost line of defence are such as to give full play to the principle of cross-firing; those between the forts of the second line are still less, enabling these latter to be all brought into play at once.

But the attack from which most danger seems to be apprehended is that from the ridge of hill lying northward of Portsmouth, and known as Portsdown Hill. We are told that “no position could be more favourable for effecting” the bombardment of the dockyard. “The distance varies from 6000 to 9000 yards; the naval establishments and ships in the harbour are in full view, and could be destroyed by an enemy who should succeed in establishing himself there for a short time.” There was no hope of doing anything with this ridge by halves, and the bold expedient has therefore been hit upon of fortifying the whole of it from one end to the other (six miles in length). The summit of the ridge, therefore, is to be occupied by four large forts, and three smaller ones (L L, &c.) A rampart and ditch is to connect them, and be continued at each end down to the shores of Portsmouth and Langston harbours, and works in advance of these flank lines (L L) are still further to cover the approach.

This forms the first or outlying line of defence, and it should be added that the formation of Portsdown Hill, which is entirely composed of chalk, and the peculiar character of the ridge which forms its summit, which is nearly a level expanse of open down, are both peculiarly favourable to the construction of extensive military works. The chalk is easily cut into the requisite ramparts and ditches, whilst the open nature of the ground, visible along its whole length by every part, affords the greatest facilities for communication; and, though Sir J. Burgoyne points out that such lines would require an army for their defence, it must be recollected at the same time that an army would be, by parity of reasoning, needed for this attack—a huge one, indeed, if the attack is to take place simultaneously along their whole extent. If, as is more probable, it were given at but one or two points, the circumstances already pointed out render concentration of the defending force comparatively easy.

The line of works on Portsdown Hill then forms, with its two flanks, the first and most important line of defence on the north. But, as on the western or Gosport side, there are two other lines within this. The first consists of the Hilsea lines (M). It will be observed that Portsmouth is built on the south-western corner of an island called Portsea Island, which is separated from the mainland by a narrow channel called Hilsea Channel, connecting Portsmouth and Langston harbours. The only roads to Portsmouth—a coach road, and the London and South Coast Railway—necessarily cross the Hilsea Channel; in fact, in this direction only is there any land access to Portsmouth at all. Along the whole of this northern end of Portsea Island runs a chain of works through which both roads pass, and which are capable of offering a formidable check to an advancing force. Hilsea lines, then, form the second line of defence on the northern side. The third is presented by the old Portsmouth lines themselves, which, like their brethren round Gosport, though inefficient to protect the dockyard from bombardment, are so far of material use in protecting the place from capture, that, if manned by an ordinarily sufficient garrison, they could not be taken without a regular siege.

Let us next turn our attention seaward, and consider the nature of the defences provided against an attack from that quarter, either on the dockyard by bombardment, or on Portsmouth altogether by capture, or on the roadstead at Spithead by a dashing cutting-out expedition; and of these three, let it be mentioned in passing, that the third appears to have been thought worthy of much careful consideration. It is pointed out that “in all former wars Spithead has been used as a perfectly secure rendezvous for a fleet; that receiving ships, sheer hulks, and many other appliances for refit, have been stationed there; extensive repairs by shipwrights, artificers, and riggers, have been carried on there, and no ships used ever to be allowed to proceed into harbour, merely for victualling and watering, or completing the ordinary supplies of stores and ammunition, and that all these operations will still require to be performed at Spithead, in addition to coaling, which will henceforth be not less important.” We are reminded that “convoys of more than a hundred sail of merchant vessels at a time have been assembled at Spithead;” and then the difficulty of stopping “by any practicable amount of fire from batteries” the passage of swift steamships dashing past at full speed, is much insisted on, and the object of the defensive works in progress or recommended seems to be not so much to prevent an enemy’s cruizers from making a swoop on Spithead altogether, as to make the place too hot for them when there.

A sea attack must come either from the westward, by way of the Needles and the Solent, or from the south-eastward. It would almost require a separate article to give any adequate idea of the defences of the Needles passage, existing, in progress, or about to be constructed. Its natural features have been already alluded to. To these must be added the combined cross and raking fires of extensive batteries at Hurst Castle, on the north, and of no less than six others, lying along the shore, or perched on the cliffs for five miles on the south. A strong boom is also to be placed, in war time, across the narrowest part of the channel, and under the guns of Hurst Castle; and it seems to be considered tolerably certain that no enemy would risk the natural difficulties of the