266 ON THE DEFENCES OF PORT JACKSON. 



I do not wish to enter into a dissertation upon the merits of 

 the different rifled guns ; it would be impossible in this paper to 

 treat of the best materials to be employed in their manufacture, 

 of the best method of rifling, or of all the details of their con- 

 struction. I have illustrated the rifling and projectiles of the 

 different heavy guns that have attracted public attention. 

 Armstrong built up guns have not yet been surpassed ; their 

 safety against bursting and the improvement recently introduced 

 in their rifling and projectiles, their accuracy and endurance, and 

 their perfect adaptability to fire spherical shot as well as cylin- 

 drical bolts with or without studs recommend them for casemate 

 guns. The shunt rifling is also better than any other except 

 Scott's rifling. The principle of both is the same, and if Scott's 

 rifling should prove the best, the Armstrong guns could be rifled 

 with the Scott groove. There would be no difficulty in doing so, 

 as the Ordnance Factories in their circulars require particularly 

 " that the form of rifling and the number of grooves should be 

 specified." The Armstrong rifled guns could be re-tubed at any 

 time when the grooves are worn out, and any ne\y rifling that 

 may have been found superior can then be introduced. 



Having to depend principally upon the Royal Artillery for 

 working our guns, it is better to place the Armstrong in their 

 hands than a strange weapon not adopted in the service. 



I cannot help expressing my admiration of the Whitworth 

 homogeneous iron guns, and particularly of the Mackay steel 

 guns, but neither the Hexagonal bore nor the Windage Adaptation 

 Ordnance have been proved to offer greater advantages than the 

 Armstrong. 



The expense of carrying out a complete system of defence 

 probably guided the Select Committee on Harbour Defences in 

 their recommendation of few heavy guns and their selection of 

 68-pounder cast iron guns. They wished probably to provide for 

 the immediate defence of Port Jackson, but it is doubtful whether 

 the 68-pounders would silence the guns of an iron-plated frigate. 

 It is easy to foresee that if the armaments of foreign powers be 

 not reduced, small armour-plated vessels with heavy guns will 

 soon be sent to foreign stations. 



