25

channels near the harbour\'s mouth are
kept clear. Assuming the area of the
whole lagoon to have an average depth
of 2 feet at low water, and taking the
rise of the tide at 3 feet, then the quan-
tity of alluvial deposit requisite to fill
up the whole to high water level, will
be 70,000,000 tons; and, allowing that
it takes place at the rate of 500,000
tons per annum, it would occupy 70
years to diminish the lagoon one half,
while its removal would involve the
constant use of 2 or 3 powerful dredg-
ing machines, at an annual cost of
£15,000 to £20,000.

This, while removing all cause for
immediate alarm as to the speedy clo-
sing up of the harbour, and showing
the expense of clearing away the whole
annual deposit by means of dredging,
at the same time proves the absolute
necessity that will arise, before the lapse
of many years, of adopting other effi-
cient means to overcome the difficulty;
and the first that suggests itself, is the
diversion of the river Tutaekuri into
its ancient bed; and should that be
found impracticable, it may be neces-
sary to construct an iron breakwater
at a cost of £200,000 to £250,000, but
this will scarcely be called for with-
in the present century. In the mean-
time, it will be requisite to employ a
Dredging Machine, to maintain the
channels spreading over the lagoon, in
order that the flow of water over its
surface, may not be impeded by the
formation of too many mud banks about
the harbour\'s mouth.

Before leaving this subject permit
me to say that, as my knowledge of the
harbour is at present imperfect, it is
probable that a more perfect knowledge
and careful observation of the change
produced by the Tutaekuri, would mo-
dify the opinions herein expressed, more
especially as regards the dredging oper-
ations.

The only other points relating to the
harbour, to which it appears necessary
to allude at present, are:—

The best means of marking the sun-
ken rock, lying N. N. E. 2½ miles from
the Bluff.

The desirability of indicating the
state of the tide to vessels arriving at
night.

The best site for, and cost of erecting
a Lighthouse.

Pania Rock being 8 feet beneath low
water level, it is practically impossible
to erect any kind of fixed beacon upon
it, and its position can therefore only
be marked by a buoy anchored near it,
which may be seen during the day at a
distance of 3 or 4 miles; and, on the
erection of the proposed Lighthouse,
the bearing of the rock being known,
vessels making the anchorage at night
will be enabled to avoid it. The cost
of a first class admiralty buoy in Eng-
land will be about ... ... £40 0 0
Anchor & Chain Cable, say 13 0 0
Freight and other charges 22 0 0

£75 0 0

The freight will be considerable on
account of the bulk of the buoy.

Pending the arrival of this, a large
puncheon might take its place. This
should be fitted with two stout straps,
having an eye forged on each, to which
should be shackled a short piece of
chain, having a large ring in the centre
to receive the end of the cable. This
puncheon with straps fitted to it, would
not cost more than 5l. or 6l.; and the
chain and anchor should be of such size
as to serve afterwards for the admiralty
buoy, on the arrival of which the pun-
cheon would doubtless be found servic-
able on some other spot.

Tidal Light.—It is desirable to pro-
vide two good signal lanterns, one to
show a red and the other a green light,
by means of which the state of the tide
could be made known to small coasting
vessels desirous of entering during the
night, and to serve also as a guide for
the Pilot should he happen to be out-
side the harbour after dark.

As these lanterns should exhibit
lights of two different colours to distin-
guish them from any other light on the
Spit, and from each other, they should
be of the best description, to compen-
sate for the loss of light incident on the
use of coloured glass, and will prob-
ably cost 45l. each, but beyond this they
would cost but little, being under the
Pilot\'s charge; and the changing of the
lamps on the turn of the tide, might be
attended to by his men, in rotation, each
performing the duty for seven days in
succession.

On the erection of the dwelling
for the Pilot and his men, a small room
should be provided in which to place
the signal lantern, and the building so
planned that a portion of it should
serve as a screen to shut in the light
from any vessel approaching too near