The Sun.
London, England, 1860-01-19 00:00:00

P ORTSMO UTH _4 NIL 17'S DEFEN CES,

The new lines of fortifications now in course of
construction for the defence of Portsmouth Dock-
yard and Arsenal, are already sufficiently advanced
to enable the spectator to form a pretty correct idea
of their plans and extent. The island of Portsea is
of an irregular oval figure, of about 16 miles in cir-
cumference, averaging more than four miles in
length, and about two in breadth. It is separated
from the mainland by the creek between Hilsea and
Cosham, uniting the harbours of Portsmouth and
Langston, and is bounded on the west by Ports-
mouth harbour, with its dockyard, gun wharf, and
victualling yard, &c., and on the south by Spithead
and St. Helen's. The only entrance to the island on
the land side is by the turnpike road over Port's-
bridge, crossing the creek already referred to be-
tween Hilsea and Cosham. A short distance in the
rear of this bridge the new line of works intended
for the defence of this portion of the island crosses
the road. extending about two miles from the
" Great Salterns" in Langston Harbour to Tipner
Lake in Portsmouth llarbour. Ascending to the top
of a portion of the casemated works of the " central
bastion" the eye can take in the whole position.
The main line of works consists of three huge bas-
tions, with flanking batteries of 10 guns each, in
casemates, on the top of ono of which we are stand-
ing. At the east and west end of the works, on the
shores of each harbour, are two demi-bastions, also
with casemated batteries. The whole of the case-
mated works on the flank of each bastion are of
brickwork, of immense extent and solidity, and
more resembling in form—with the arches spring-
ing overhead from their piers—the cloisters of some
monster cathedral than a simple battery of 10 guns.
In the rear of each gun is a barrack-room for the
accommodation of the 10 men belonging to each
gun. Peculiar means are adopted to clear the
interior of the works from the smoke of the guns.
All parts of the brickwork that come in contact
with earth are faced with glazed bricks, laid with
cement. The top of the brickwork is covered in
the usual manner with concrete, Seyssel asphalt,
and earth, the latter to a depth in some parts of 10
feet. A rampart of earth will also face the brick-
work of these casemates to a depth of 25 feet. The
faces of the bastions are of earth. The base of the
whole of the line will be 116 feet by 30 feet in
height. The number of guns which will be mounted
on the main bastions and on the top of the whole
line of works has not yet been decided on, as it will
be yet upwards of three years before they are com-
plete. At the present time6oo,ooo bricks are being
used weekly in their construction. In front of this
main line will run a moat 150 feet wide, with means
of closing each end at high water. In advance of
the main line of works will bo constructed three
triangular-shaped outworks of enormous strength
and extent, probably the largest of their kind in
the world. They will be connected with the main
defences by draw-bridges, covert-ways, &e., and
strengthened by every means known to modern
engineering science. Through the eastern work
will pass the line of railway to the town, and
through the western one the public turnpike road,
which for this purpose will be diverted to the west-
ward of its present course, passing through Tile
Barn Farm, and again joining the old road near
Cosham. In ra3:ing over the works the turnpike
road crosses three extensive moats, in addition to
the creek separating the island from the mainland.
This creek, considerably deepened, and increased in
width to 200 ft., runs along in front of the whole posi-
tion, and will enable a fleet of gunboats to pass to li
and fro between the harbours of Portsmouth and
Langston, mad act in conjunction with the lino of
works on either flank, in the event of an attack by
hostile troops, who, after effecting a landiagto the
eastward or westward of the port, must aavance
along the Fareham or Chichester roads, and can
only attack the front of the position with a cer-
tainty of marching along a narrow causeway to de-
struction. So far the position appears impregnable;
but, recollecting that we are supposed to be stand-
ing in a central position of the main works, that the
crest of Portsdown-hill stands in frowning grandeur
in your front, at a distance of only 2,250 yards, and
that batteries can be placed at 2,000 yards, you feel
uncomfortable in the midst of your contemplation of
your fancied security in the event of a siege, with
an enemy in possession of Portsdown ; and this feel-
ing is not very much diminished even when you are
told that with the present height of parapet the line
of defence is perfectly sheltered from any artillery
planted at Portsdown, and that nothing can affect
it except a vertical fire. As the works have been
much criticised in military circles on this very point
we will quit them and ascend Portsdown. A mag-
nificent view lies spread out before us, and appa-
rently at our feet lies Portsmouth Dockyard, its
harbour and shipping; and, in dangerous proximity
to the western demi-bastion, and within short rang.
of us, lies Tipper, with its extensive powder maga-
zines. Portsdown-hill is evidently the key of the
whole position, and whichever troops held it in pos-
session could with impunity destroy or protect the
dockyard and shipping in Portsmouth Harbour at
their pleasure. It has been urged that with the
"Hill" so near to the garrison of Portsmouth, should
a war break out at any time with a powerful neigh-
bour which might render invasion possible,
a few thousand troops from the garrison could
in a few days render it quite impregnable, and
for that reason the erection of works at the pre-
sent time would be a waste of public money.
Returning to the easternmost point of the new
line of defence, we find that the guns from its
demi-bastion cross their fire with those of Cum-
berland Fort, at the entrance of Langston Harbour,
a regularly fortified work, mounted with 46 pieces
of heavy ordnance, and now occupied by the Royal
Marine Artillery. "Within short range is a new
fort to mount 17 guns, in course of °recant on the
site of the old " Lumps" fort ; and at an equal dis-
tine() further to the westward stands Southsea
Castle, with its auxiliary earthwork s, and defendin
with its numerous 8-inch guns the entrance thetof
harbour channel by the " Spit" buoy. The sea...e,e,
of Portsmouth lines, with their 8-inch and lon,, 0--
guns
pounders, and Blockhouse Fort, with. its 56
of the same calibre, rakinie
the hal bour channel,
complete the cordon of defenceof the island of
Portsea so far, but, with the new works in progress
on the opposite side of the harbour, and theo ne..ha
ini-t.
in-
tended sea forts, do not in reality cornpiis
its defences. The boring operations in connection
with the foundations of the two sea forts on the
"Noman" and "Dean" shoals are being ea/lied on
under the superintendence of Sir Charles Fox.
Each fort will mount 100 guns, and will command
the narrowest part of the entrance at the east end
of the Isle of Wight to Spithead from the sea. At
the western or Needles entrance are the works of
Hurst Castle, 68 guns ; Fort Victoria, 52 guns ;
and Cliff end Fort, 40 guns. All these guns are of
the heaviest calibre. Recommencing our descrip-
tion from Blockhouse Fort at the entrance of Ports-
mouth Harbour; on the opposite point of the penin•