regard to its Defence. 219 



obliquely/ Their parapets must be 18 feet thick at least, 

 15 feet being the penetration of a 24 -pounder ball into 

 earth. 



In conclusion, I would remark that my suggestions 

 would be, — at Sandy Bay a simple Battery of two faces, one 

 up and another down the river, — on the side and near the 

 top of Mount Nelson, an American block-house, — and in rear 

 of the town smaller block-houses of simpler construction, 

 joined where necessary by curtains of abattis, troups de 

 loup, entanglement, or fortified hedges or walls, — at Battery 

 and Macquarie Points, (Plate II.) simple but well-defined 

 batteries, — at Kangaroo Bluff another American block-house 

 armed with artillery, — and at the little Point below a smaller 

 block-house, armed with a swivel on the roof, to command 

 the Bay, &c., beyond it, 



I have, on the plates, copied diagrams from the best 

 authorities; the survey of the neighbourhood (Plate I.,) and 

 a few of the diagrams, are my own. 



To fortify the place by detached works of a permanent 

 nature might be too expensive to be at once carried out ; 

 still, the spots I have indicated might at any rate be re- 

 served for purposes of defence, and the works I have described 

 might be traced and picketed off, to be constructed when 

 necessary, if only as a line of field works. Many of my 

 readers are probably far more conversant with the matter in 

 hand than I am ; — let such, I would say, remember that a 

 humble though earnest follower of the arts of which they 

 are masters has offered his ideas for them to enlarge and 

 improve upon, and that in doing so a hope of being instru- 

 mental in good alone has actuated him. 



2 F 



