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. 



Remarks Before referring to the plans for the security of the principal 



guns, sub- places of New Zealand, I will make some general remarks respecting 



marine mines, 



&c ' g uns anc \ 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 first 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 681b. 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 2,0001b. in weight, the charge is 5501b. of gunpowder, i.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 



