The Cambridge History of India, Vol. I: Ancient India v1.c15.125

v1.c15.125

In the north-east corner of Irān, west of the Punjab, a great triangular bundle of mountain ridges splays out westward and southward from the north-east. These ridges and the intervening valleys constitute Afghānistān. Flowing from the Afghān valleys we have on the one hand the Kābul river, which descends eastward to the Indus, and on the other hand the greater river Helmand, which flows south-westward into the depressed basin of Seistān in the very heart of Irān. There the Helmand divides into many channels, forming as it were an inland delta, from which the waters are evaporated by the hot air, for there is no opening to the sea. The valley of the Kābul river on the one hand, and the oasis of Seistān on the other, might in the hands of an enemy become bases wherein to prepare for the invasion of India. Therefore, without annexing this intricate and difficult upland, we have declared it to be the policy of Britain to exclude from Afghānistān and from Seistān all foreign powers.