Anniversary Address. xxix. 
2,000 yards. It is, however, desirable that a few pieces of greater 
power should also be mounted on the batteries. I therefore consider 
that a few of the latest type of 8-inch breech-loading guns shall 
form part of the armament. These will pierce 7 inches of iron at 
3,000 yards. 
The question of the power of gun required in the defensive 
batteries of course depends upon the description of vessels by which 
these colonies may be attacked. All authorities agree that ships of 
war, of some sort, may make a descent upon Australasia, but a dif- 
ference of opinion sometimes arises as to whether a hostile iron-clad 
is likely to appear in these waters. "Though I believe that the class 
of vessel by which we are most likely to be attacked is a swift ship, 
of great coal-carrying power, such as I will hereafter describe, it 
appears to me that, in determining on our plans, it would be unwise 
to act on the assumption that vessels protected by iron-plates, in 
greater or less degree, may not be employed in the attack, 
As regards the designs of the works for the reception of the SUNS pesigns for 
already in the colony, as the carriages and platforms supplied for "*tteries. 
them are arranged for batteries “en barbette” (see Plate IV.), i.e., 
guns with a wide sweep firing over a parapet, that system will, as a 
rule, be adopted. The only exception to this will be in a case, to 
which I shall hereafter refer, where it will be necessary to place the 
guns in casemates in order to protect them from fire from heights in 
their rear. 
With respect to the guns not yet provided, it is proposed that 
they shall' be mounted on “ disappearing” carriages by means of 
which—excepting at the time of actual firing, when the gun and one 
man only is exposed—both gun and gunners are absolutely protected 
from an enemy's fire. ; 
I pass on to consider the use of submarine mines, which should, submarine 
when practicable, be employed in the defence of harbours, in order to "2e 
stop an enemy's ships and detain them under the fire of the 
batteries. I am glad to find that Admiral Scott, of Dunedin, so well 
known at the Admiralty for the great improvements which he effected 
in regard to ships' gun-carriages, is specially advocating the adoption 
of this element of defence. 
Twenty years ago there was very little method in employing these 
engines of war, but now the application of them has become quite a 
complicated science. 
They may be divided into three classes, viz., mechanical mines, 
observation mines, and electro-contact mines, 
