Remarks 
respecting 
guns, sub- 
marine mines, 
&c. 
` 
xxviii. New Zealand Institute, 
as practicable with other means of defence. At or near most of the 
places last named, field forces of riflemen and field guns would also 
be available for their protection. 
Before referring to the plans for the security of the principal 
places of New Zealand, I will make some general remarks respecting 
guns and submarine mines, and the mode in which they should be 
applied. 
I wish for a moment to draw your attention to the enormous 
increase which has taken place during the last twenty-five or thirty 
years in the size and power of guns.. 
When I frst had to deal with fortification works, in 1852, and 
for several years afterwards, the most powerful piece of artillery 
was the smooth-bore 68-pounder. Now we have guns of 100 tons 
weight. In the large diagram before you, you see the 68-pounder 
shown inside the 100-ton muzzle-loading gun. The length of the 
68-pounder is 10ft., whilst that of the 100-ton gun is 32ft. 6in. 
Here is a model of the 68lb. shot and of the cartridge for that gun; 
there is a model of the missile and charge for the 100-ton gun. The 
missile is 2,000lb. in weight, the charge is 550lb. of gunpowder, t.e., 
five barrels and a half, and the two together measure about 10ft. in 
length! I may mention that some of these 100-ton guns are actually 
mounted at Gibraltar and Malta. In the more recent manufacture of 
powerful guns, however, breech-loading has been adopted, and the 
calibre reduced, whilst the length of the piece is increased, in order 
to provide the required capacity for the expansion of the gases of 
the very large charges used, which consist of very slow-burning 
powder. There are guns now in existence on this principle of 70 to 
75 tons weight, which are superior in power to the 100-ton gun to 
which I have just referred. 
It is scarcely necessary for me to say that I do not suggest that 
such enormous guns as those to which I have just referred shall be 
employed in the defences of New Zealand. Ships carrying armour 
of a thickness which these pieces are intended to pierce are not 
likely to find their way to Australasia. 
The Government of New Zealand, in 1878, acting on the advice of 
a Committee assembled in London to consider questions relating to 
the defences of the colonies, procured from England a number of 
7-inch and 64-pounder muzzle-loading rifled guns. These will form 
a considerable portion of the armament of the proposed works. 
The 64-pounder is not an armour-piercing piece, though effective 
against vessels unprotected with iron plating; but the 7-inch gun is 
calculated to pierce 7 inches of iron at 1,000 yards, and 6 inches at 
