Poxp.—Notes on the firing of Torpedoes by Electricity. 167 
. 14 fathoms at low tide, while projecting from Rangitoto is a bank with only 
23 fathoms, giving only 1,400 yards of channel to the bank on the south 
side, while midway is the shallow bank about 400 yards long, thus reducing 
the distanee to be defended to less than 1,000 yards. It will thus be seen 
that fewer torpedoes will be required to defend this passage, and the North 
Head would be directly at right angles to it, thus placing it very favourably 
for direct observation, while the highland to the west of the Tamaki Heads 
would prove a favourable position for observation from whence to signal, 
either by flags, lights or telegraph, the approach of the enemy to the first 
line of the defence. I would pay especial attention to this passage, as I 
think it very likely an enemy would choose that, anticipating that the most 
used channel would be the best guarded. And it must be borne in mind 
. that the days for attack by sailing craft are past, and that, if Auckland 
was attacked, it would be by several steamers and not one only, as no 
enemy would do so hazardous a thing as to send in an unpiloted and 
unattended steamer, as the slightest mishap to vessel or machinery would 
at such a time place her at the mercy of those she came to molest ; nor is it 
likely that small, light draught cruisers would be chosen for the work, as in 
the South Pacific there are no naval stations where the attacking squadron 
would be safe from the British navy then on the station, or where they 
could provision, coal, or dock, therefore large vessels alone would be 
enabled to attempt the work, and again a light draught vessel would be 
unable to carry an armament sufficiently powerful to do any damage at 
long range. 
With respect to the distance of Auckland from the respective outer lines 
of proposed defence, I find from the Admiralty Chart that the centre of the 
first line in Rangitoto Channel is 200 yards less than five miles, but this 
would be reduced to 4$ miles should the vessel stand well in to the bank, 
still keeping outside the line; this is measured to the lower part of Queen 
Street, but by his standing in so close it would preclude him from seeing 
any portion of Auckland district unless from his mast-head, and then the 
only places which he could observe would be Mount Eden, Mount Hobson, 
and perhaps one or two other points of the high land, and from this position 
I do not think we have anything to fear from shot or shell falling into the 
city, as irrespective of the distance he has no point on which to concentrate 
his fire, and certainly none on which to observe the effect of his work, 
But from the Koreho Channel the position is altered, as here he has full 
view of the town, which he could absolutely rake provided he had artillery 
which would carry far enough; but the distance from this point to the 
lower part of Queen Street is five miles and 800 yards, and here again must 
be borne strongly in mind the fact that guns heavy enough to throw shell 
