On the Defences of Port Jackson, 

 By G. A. MORELL, ESQ., C.E. 



[Read September 6th, 1865.] 



IT is generally admitted that the effectual defence of Port 

 Jackson presents many difficulties. Not one of the several 

 projects that have been proposed at different times seems to fulfil 

 entirely and satisfactorily the object in view, viz., the possibility 

 of preventing an enemy from entering Port Jackson, or the cer- 

 tainty of having such advantage over him from our batteries, as 

 to oblige him to surrender or retreat if we permit him to enter 

 the Harbour. These difficulties arise chiefly from the extent of 

 Coast to be fortified, which encloses an area of about ten square 

 miles, and has no less than twenty Points, Headlands, or Islands, 

 and twenty Bays or Coves to be commanded or covered, and also 

 from the enormous expense required to complete extensive and 

 effective works, and to maintain a large military force to man 

 them. 



Any complete system of defence for Port Jackson, if ex- 

 tended from Sydney to the Heads, would be too costly for the 

 Colony at present ; but batteries might be commenced to afford 

 temporary defence, with a view to their being afterwards con- 

 verted into works of such power as to render them efficient and 

 secure. 



The probability of being obliged to strengthen our defensive 

 works in a co-relative proportion to the advance of Military 

 science, was overlooked in the construction of our present 

 batteries, and in our future works we must not forget the rapid 

 improvements that are made daily in the heavy artillery and 

 vessels of war likely to be brought against us. 



It must be admitted that whether we have or have not the 

 co-operation of English Men-of-War or of a Colonial Navy, 

 batteries and forts are indispensible for the defence of our 

 Harbour. 



