The Indus As A Frontier Line.

Streams generally are less valuable as a defence than mountains, as they fall by one defeat and allow of no after defence, as in the case of mountains; all direct defence of rivers resolves itself into a defence by posts, the most dangerous of all defence and least to be trusted to. An indirect defence can never stand before "superior numbers" which must eventually make themselves felt, and it has been demonstrated that these numbers may be swelled to 700,000 men after ten years of peaceful occupation of Afghánistán.