In a thickly-wooded country the obstacle to sight preponderates; in a mountainous country, the difficulty of movement presents the greatest obstacle to an enemy; in countries very much cultivated both these obstacles exist in a medium degree. As thick woods render great portions of ground in a certain manner impracticable for military movements, and as, besides the difficulty which they oppose to movement they also obstruct the view, thereby preventing the use of means to clear a passage, the result is that they simplify the measures to be adopted on one side in proportion as they increase the difficulties with which the other side has to contend. Although it is difficult practically to concentrate forces for action in a wooded country, still a partition of forces does not take place to the same extent as it usually does in a mountainous country, or in a country very much intersected with canals, rivers, &c.: in other words, the partition of forces in such a country is more unavoidable but not so great. In mountains, the obstacles to movement preponderate and take effect in two ways, because in some parts the country is quite impassable, and where it is practicable we must move slower and with greater difficulty. On this account the rapidity of all movements is much diminished in mountains, and all operations are mixed up with a larger quantity of the element of time. But the ground in mountains has also the special property peculiar to itself, that one point commands another. We shall devote the following chapter to the discussion of the subject of commanding heights generally, and shall only here remark that it is this peculiarity which causes the great partition of forces in operations carried on amongst mountains, for particular points thus acquire importance from the influence they have upon other points in addition to any intrinsic value which they have in themselves.