[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 particular facilities, in {p.189} a word, for accumulating successful numbers at a threatened point of a stationary defence, which the British would not have had in an active campaign of retreat.