2 
would be carried out as soon as it was determined to place the fortress in a state 
of defence. 
Fie. 1. 
B 
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eh coae aan Late aia 
her ey 
BA . 40 
Dake BAN OE 
ADVANCED aINS OB DEF ey, S 
aN Ay! S 
MAIN Line 
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us ee 
2175 2175 YARDS 
Scheme of Defensive Arrangements for a large Fortress. @ Permanent works. 
e Field and improvised works. 
c E 
A_«<QirE SSS 
Section on the line A B. Case of level unaccentuated ground. 
7 i I / 
o Cc D E p ’ 
0 
Section on the line A B’. Hilly accentuated ground. 
The functions of the main line of defence are— 
(1.) By the fire of its guns to support the mobile army in the defence of the 
advanced position. 
(2.) To offer an obstinate resistance after that army has been defeated and 
driven in. 
(3.) To protect the central nucleus from bombardment. 
This main line may be said to form the tracing of a gigantic polygon in which 
the permanent forts form the bastions and the lines in the intervals the curtains. 
The lines in the intervals should follow the crest line of a ridge or ridges and 
the forts be constructed on commanding points on these ridges. 
The functions of the enceinte or defences of the central nucleus is to guard it, 
i.e. the town or city defended, from capture or raid by small parties who having 
penetrated the main line at some point have pursued their advantage so far, and to 
make it a place of refuge secure against a coup de main. 
For this purpose a slight profile formed by a ditch 13” to 14” deep and 13 to 
16 yards wide with a parapet 33” to 39” thick having a command of from 16” to 
20" would suftice, 
