There remained, therefore, some fifty miles of gorge which had not been, and could not be, explored, and the information about it was only indirect. From Lagung upstream to where the Po-Tsangpo joined the Tsangpo, lay a stretch which many natives had visited. The altitude of the junction was estimated at 5,700 feet, which would give a drop of 3,090 feet in the seventy-five miles down to their observation of 2,610 feet--a fall of some 41 feet per mile. Here there was clearly no waterfall. From the junction of the two streams to the point where Captain Bailey turned back was not more than twenty miles, and the drop 1,780 feet, giving a fall of 89 feet a mile. The Monbas whom he met told him that they had hunted on the right bank of the stream throughout this unknown stretch, and that, though there were many rapids, there were no big cascades. We are not concerned with the rest of the journey of Captain Bailey and Captain Morshead, which took them upstream to Tsetang, where Nain Singh had gone in 1874, and back to India by the wild country of the Bhutan border. Their evidence may be considered to have finally solved the riddle of how the great river breaks through the highest range on the globe. It does it by means of a hundred miles of marvellous gorges, where the stream foams in rapids, but there is no fall more considerable than can be found in many a Scottish salmon river. I am not sure that the reality is not more impressive than the romantic expectation. The mighty current is not tossed in spray over a great cliff, but during the æons it has bitten a deep trough through that formidable rock wall. Curiously enough, the rivers which break through the Himalaya chose the highest parts of the range through which to cut. South of Pemakochung is the great peak of Namcha Barwa, 25,445 feet high; north of it is the peak of Gyala Peri, 23,460 feet. The distance between these mountains is only some fourteen miles, and through this gap, at an altitude of just under 9,000 feet, flows the great river. III THE NORTH POLE THE NORTH POLE (_Map_, p. 80.) I When sceptical people say that Polar exploration has been of no benefit to mankind, it is permissible to think that their judgment is as unsound as their point of view is limited. Not only have Polar explorers added enormously to the scientific knowledge of the world, but they have also materially aided commerce. But even if these voyages had been barren of scientific and commercial results, they would have been infinitely worth making. For among Polar explorers are many men who must be universally regarded as heroes. No training was more rigorous and dangerous, no work has ever called for more endurance, resource, and courage. A nation which is without its heroes is in a sad plight; a nation which has them and ignores their example can only be looked upon with pity. The spirit of high adventure is one that no country can afford to neglect.