~The Hindu Kush.~--The Muztagh chain from the south-east, the Sarikol from the north-east, and the Hindu Kush from the south-west, meet at a point to the north of Hunza. The last runs westward and south-westward for about 200 miles to the Dorah pass (14,800 feet), separating the valleys which drain into the Indus from the head waters of the Oxus, and Hunza and Gilgit in Kashmir and Chitral in British India from the Afghan province of Wakhan. The highest point in the main axis, Sad Istragh (24,171 feet), is in this section. But the finest mountain scenery in the Hindu Kush is in the great spurs it thrusts out southwards to flank the glens which feed the Gilgit and Chitral rivers. Tirach Mir towers above Chitral to a height of 25,426 feet. From Tibet to the Dorah pass the northern frontier of India is impregnable. It is pierced by one or two difficult trade routes strewn with the bones of pack animals, but no large army has ever marched across it for the invasion of India. West of the Dorah pass the general level of the Hindu Kush is a good deal lower than that of its eastern section. The vital point in the defences of India in this quarter lies near Charikar to the north of Kabul, where the chain thins out, and three practicable passes debouch on the valley of the Kabul river. It is this fact that gives the town of Kabul its great strategic importance. The highest of the three passes, the Kaoshan or Hindu Kush (dead Hindu), crosses the chain at an elevation of 14,340 feet. It took its own name from the fate that befel a Hindu army when attempting to cross it, and has handed it on to the whole range. It is the pass which the armies of Alexander and Babar used. The historical road for the invasion of India on this side has been by Charikar and the valley of the Kabul river to its junction with the Kunar below Jalalabad, thence up the Kunar valley and over one of the practicable passes which connect its eastern watershed with the Panjkora and Swat river valleys, whence the descent on Peshawar is easy. This is the route by which Alexander led the wing of the Grecian army which he commanded in person, and the one followed by Babar in 1518-19. Like Alexander, Babar fought his way through Bajaur, and crossed the Indus above Attock. [Illustration: Fig. 10. The Khaibar Road.] ~The Khaibar.~--A British force advancing on Kabul from Peshawar has never marched by the Kunar and Kabul valley route. It has always taken the Khaibar road, which only follows the Kabul river for less than one-third of the 170 miles which separate Peshawar from the Amir's capital. The military road from Peshawar to Landikhana lies far to the south of the river, from which it is shut off by difficult and rugged country held by the Mohmands.