ng these the most recently conspicuous was the occupation of Plevna
by the Turks in 1877, and the long consequent arrest of the Russian
progress; but Mantua, in 1796, in like manner and for the same
reasons, effectually stopped Bonaparte for eight months, and Genoa, in
1800, so long delayed the Austrians as to reverse the issues of the
campaign signalised by the name of Marengo.

[Footnote 15: I should greatly like here to take up
my parable against those who base their
calculations for the numbers and kinds of naval
vessels upon the idea of "a navy for defence only";
but space and relevancy both forbid.]

From the simply defensive point of view, a line of works arranged
consecutively around such a stationary centre has no flanks to be
turned, but resembles a circle or other continuous curve which returns
into itself. Like a straight line, such a curve may be broken by
superior force; but until that is done the weakness of flanks does not
exist. Moreover, succour can be more quickly sent from a centre to
every threatened point of the circumference than from the middle of a
line of equal length to its extremes. A circle, therefore, is the most
compact disposition for defence, and so most ideal for smaller
numbers. It is concentration in its most effective {p.188} form,
while sacrificing nothing in elasticity and flexibility of motion.

These are the intrinsic defensive advantages--as distinguished from
the offensive threat to the enemy's communications--secured to the
weaker party by a permanent position, and these are its compensations
for the loss of open communications which have been deliberately
abandoned.

In Natal, at the end of October, 1899, the British army was much
inferior to the enemy in both numbers and mobility; and while several
lines of defence were to be found in the region behind, as was shown
by the stubborn resistance which the Boers, when in turn outnumbered,
made at the Tugela, these positions were open to the danger of being
turned by superior numbers or superior rapidity; still more when these
two were combined. In fact, much of the subsequent Boer success in
defence resulted from the fact that, acting on the inside of an arc,
with the advantage of interior--shorter--lines, they also moved over
the latter with greater speed, owing to their distinguishing
characteristic as mounted troops. They had pa