On landing at the jetty one finds that he is within an enclosure of several acres,
fenced off by a substantial two-railed fence, while a short distance to the left from
the landing a queer shaped ditch has been dug and the earth excavated thrown up in
what appears at first sight to be a very promiscuous manner. The works in
progress at this spot are to form a very important link in the system of defences
which are being carried out on the recommendation of Colonel Scratchley and upon
which Brisbane will have, to a very great extent, to depend for safety in case of
invasion.
On the hill (henceforth to be known as Signal Hill) overlooking the southern portion
of the bay, a large building has also just been erected, which is to serve the double
purpose of a reformatory for boys in time of peace, and as an additional means of
defence in the event of any warlike demonstration being made against the
metropolis.
The battery being formed on the flat, at a short distance from the river, is intended
to prevent an enemy's vessels entering the river, and to protect the submarine
defences intended to bar their progress should they succeed in getting into the
stream. The ditch forming the outer extremity of the works has been excavated and
the earth thrown up inside, so as to form the parapet of the fortifications, but further
progress has been delayed pending the arrival from England of the cement required
for the internal work.
The ditch forming the outer boundary of the fortifications is pentagonal in shape, is
forty-six feet wide at the top, the sides sloping down to a width of sixteen feet at the
bottom, and is sixteen feet deep. It is nearly a quarter of a mile in length, it
encloses an area of about 900 square yards, or a little less than two acres, and the
quantity of earth excavated from it is from l8,000 to l9,000 cubic yards. Around the
inside of the ditch is a small level space called the "berm", from the inner edge of
which rises the parapet, formed by the earth thrown up from the ditch."
The right face of this parapet looks towards Moreton Bay, while the left faces almost
directly across the river. The right face has a width of sixty feet at the base, with an
extreme height of twenty-five feet, while the river face has a mean height of sixteen
feet. On the former will be placed two six-inch or four and a half ton muzzle-loading guns, placed at an elevation of sixteen feet above parade level. These guns,
made by Sir William Armstrong and Co., will be made of the latest pattern, will fire
projectiles varying from œ50 to œ90 in weight, the average charge being œ25 and,
with a battering charge of œ33 of pebble powder, they will be capable, at a close
range, of piercing eleven to twelve inches of wrought iron armour plates. On the
left face will be placed two 64-pounder muzzle-loading rifled guns, at an elevation
of five feet above the parade level, the extra elevation and larger size of the
ordnance in the former case being provided on account of the right face being most
exposed to attack. In the rear will be "emplacements" for two field guns intended to
defend the fort from a land attack.
Inside of the right face will be situated the barracks for the garrison, powder
magazine and shell-room. From the magazine, passages will communicate with the
guns, the serving of which will be facilitated by means of a lifting tackle travelling
on a rail in the roof of these passages. The loading gallery, or chamber, will be
vaulted in brickwork, and protected by aprons of cement concrete. The whole of the
work of serving and loading the guns will be carried on under cover, the only man
who will be exposed to the fire of an enemy being the "number" aiming the guns.
The guns are to be mounted on wrought-iron carriages, traversing platforms
arranged on the same principle as railway turntables, by means of which the pieces
can be readily brought to bear on any required point. The whole of the work
connected with the gun platforms, barracks, and magazines will be carried out in
the most substantial manner, with the cement concrete foundations and outer walls,
the lining being of hard brick laid in cement varying in thickness from two to three
feet, and the protecting concrete ranging from seven to eight feet in thickness.
The rear of the fort is protected by a parapet twenty feet in height, and under cover
of this will be placed timber buildings to serve as officers' quarters, guard and
cooking houses, ablution sheds, etc. The entrance to the fort is to be by drawbridge
placed at the eastern end of the rear parapet, and under cover of the right flank.
The passage forming the entrance will pass through the parapet, the sides and roof
of the passage being logged with heavy square timber bolted together.
The entrance will be closed by heavily-framed wooden gate, sheeted with iron at the
back. A strong fixed bridge at present spans the ditch at the rear of the fort, but
after the heavy guns have been taken across, this will be removed and the
drawbridge erected.
The appearance of the battery from the river will be that of a large earth
embankment, no masonry being exposed, and the guns will be mounted to fire en
barbette, that is to say, over the parapet. They will be given great lateral sweep, so
as to command any portion of the River in the vicinity with artillery fire.
The 64 pounders mentioned are now in the colony, and will be mounted on high carriages of a new and improved pattern.
The Adjutant: