248 ON THE DEFENCES OF PORT JACKSON, 



the approaches being so extensive 'and well commanded, safe 

 retreat being secured in case of a reverse, the practicability of 

 affording re-enforcements to other positions, if needed, by land 

 or by water, together with the fitness of the ground to contain 

 Shell-proof works and barracks, and to command every battery 

 we might have from Darling Point to the entrance of the Harbour, 

 indicate it as the best position on the North Shore for Head- 

 quarters for the number of troops to be permanently kept in 

 readiness against the attacks of an enemy. . Vessels steaming 5 

 knots per hour must be exposed to the full fire of batteries on 

 George Head for 25 minutes, at a less range than 2000 yards, 

 and within that same range, the guns of George Head will cross 

 fire with those of every battery as far as Point Piper. Vessels 

 forcing a passage through obstructions thrown across the channels 

 would be followed by the guns of George Head until past Bradley 

 Head. 



4. On examination of the ground from Inner South Head 

 Lighthouse to the Gap, we find that the first point north of the 

 Gap Bluff is decidedly the best for a battery. There is no inter- 

 vening ground to interfere with the fire of guns as at each of the 

 other plateaux towards the Lighthouse. This position might be 

 of value with long range guns. Vessels entering by the East 

 Channel would be exposed to the fire of the guns of a battery on 

 Inner South Head for 28 minutes, within a range of 2000 yards, 

 but only for 4 minutes within a range of 1000 yards. Engaging 

 vessels at sea, which could easily keep out of 1000 yards range, 

 would prove almost a waste of ammunition, as the elevation of the 

 guns would vary at every shot. At night this battery would be 

 nearly useless. It is too far from Watsons Bay for tactical opera- 

 tions, although it is invaluable as a look-out from which to trans- 

 mit information by Electric Telegraph to other batteries. 



5. Green Point is strategically a very good position ; a 

 battery there is necessary. Vessels entering by the East Channel 

 would be raked fore and aft by its guns nearly point blank, being 

 fully exposed to their fire for 12 minutes within a range of 1000 

 yards, and for 20 minutes within 2000 yards ; entering by the 

 West Channel vessels would lie 16 minutes only within the same 

 range, but a low ricochetting fire from Green Point would be 



