L A N D A X D W A T E R 
December ii, 1915. 
force to holi' an extensive perimeter has disap- 
peared. 
It has been proved, upon the other hand, that 
continuoiH trenches consoUdated by a sviftic ieiit 
labour spread over a sufficient time, can be held 
ahiiost indelinitely, so long as there is a sufficient 
supply of men, machine guns and light and heavy 
artillery. A position of this sort held by a sufficient 
number of men can to-day be maintained against 
a much larger force. 
It has equally been proved that the number 
of men per mile cannot safely be allowed to fall as 
low as 3,000, and that you hardly have security 
until you are certain of nearly or quite 5,000 men 
a mile : Mobile of course and capable of rapid 
concentration to meet pressure on anv special 
sector, but on the average close on 5,000 men a 
mile. All the German resistance in the West 
]ias proved this. 
This, which has proved generally true of the 
. whole war for a year, supposing the defensive to 
be amply mvmitioned and equipped, is particularl\- 
true of an attempt to defend Salonika because 
there could not be brought up in useful time any 
very considerable weight of heavy guns — nothing 
corresponding to the artillery which has been 
found necessary to shake an entrenched position 
in other theatres of the war. Add to these ele- 
ments the fact that the Allies have command of 
the sea, and we are in a position to examine the 
Salonika problem in detail. 
The first thing that strikes us is that the con- 
formation of the coast line round Salonika is a 
handicap to such a continuous defensive line. It 
demands more men than other conformations 
would. 
There are roughly speaking three types of 
port,, the defence of which may be called respec- 
tively the defence of a coastal line, a peninsula 
and a gulf, or estuary. If, as in Diagram I, 
you have a straight coast running as does the 
coast A-B, and you have to defend a port at C 
with only enough men to line a perimeter of 40 
or 50 miles, you can, if the ground favours you, 
establish lines upon a radius of about 12 miles, 
^'ou ha\-e onl\- half a circle to defend (supposing 
always you have command of the sea). 
if, as in Fig. 2 of Diagram I your port stands 
on a peninsula you can defend it, if you have 
command of the sea, with comparatively few men 
upon a short perimeter, the neck of the peninsula 
from A-B : Portsmouth is an ideal position of 
this kind. But if your port is on a gulf or estuarj', 
as in Fig. 3, then you are condemned to spread 
out your men o\'er very nearly a full circle. And 
therefore a given number of men will be harder 
put to it to defend a port of the 3rd type than 
either of the two others. For it is essential to 
the stability of such an entrenched line that its 
ends should repose either upon the sea which one 
commands, or upon some other impassable obstacle. 
Now Salonika is of this third kind, and the 
forces defending it will have to be spread out upon 
more than three-quarters of a circle. In other words, 
your minimum number of men is badly handi- 
capped by having a line of positions stretched over 
the greater part of a circle all round the spot to 
be defended. And it must be remembered that 
such a spot, if it is a town with shipping and depots, 
must be defended by a line fairly far out even at 
its nearest point, in order to protect the buildings 
and the quays from long range fire. If Salonika 
were situated upon a peninsula, as is Lisbon, one 
might conceive the renewal here of Torres Ved "as. 
Situated as it is at the end of a gulf no To. res 
Vedras is possible, only a great horse-shoe of p isi- 
tions demanding an extended line. 
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