itself; immense branches launch into the adjacent country in curved lines, and lift themselves often just at their termination to a greater height than the main ridge itself; promontories then join on, and form deep valleys which do not correspond with the general system. Thus it is that, when several lines of mountains cross each other, or at those points from which they branch out, the conception of a small band or belt is completely at an end, and gives place to mountain and water lines radiating from a centre in the form of a star.
From this it follows, and it will strike those who have examined mountain-masses in this manner the more forcibly, that the idea of a systematic disposition is out of the question, and that to adhere to such an idea as a fundamental principle for our measures would be wholly impracticable. There is still one important point to notice belonging to the province of practical application.
If we look closely at mountain warfare in its tactical aspects, it is evident that these are of two principal kinds, the first of which is the defence of steep slopes, the second is that of narrow valleys. Now this last, which is often, indeed almost generally, highly favourable to the action of the defence, is not very compatible with the disposition on the principal ridge, for the occupation of the valley itself is often required and that at its outer extremity nearest to the open country, not at its commencement, because there its sides are steeper. Besides, this defence of valleys offers a means of defending mountainous districts, even when the ridge itself affords no position which can be occupied; the rôle which it performs is, therefore, generally greater in proportion as the masses of the mountains are higher and more inaccessible.
The result of all these considerations is, that we must entirely give up the idea of a defensible line more or less regular, and coincident with one of the geological lines, and must look upon a mountain range as merely a surface intersected and broken with inequalities and obstacles strewed