In 1881 Wrangell Island was thoroughly explored by another search expedition, that of Captain Berry in the American ship _Rodgers_, who was in these parts looking out for traces of the _Jeannette_. He found it to be, not a continent as some had supposed, but an island forty miles broad and sixty-six miles long, about thirty miles from Herald Island and eighty from the Siberian coast; and on it, as on all these Siberian islands and the coast of Alaska, remains of the mammoth were found. Examining the ice to the northward, he reached 73° 44´ in 171° 30´, being fifty-three miles further north than Kellett and twenty-four miles further than Collinson in 1850. Returning from the north to winter quarters he achieved another Arctic record in his ship being destroyed by fire in St. Lawrence Bay on the Asiatic side of Bering Strait. Opposite this, on the American side, from Cape York downwards the land trends away to the south-east to Norton Sound, in which are the mouths of the Yukon, one of the mightiest rivers of the world, its volume being as great as, or according to some writers greater than, the Mississippi. In a course of two thousand miles it runs northwards to the Arctic Circle at the now abandoned trading post of Fort Yukon, where its waters are reinforced by its tributary, the Rat or Porcupine, coming in from the north-east, and given their seaward direction to the south-west. Up this vast waterway in 1866 went Frederick Whymper and William H. Dall. Beginning with a sledge journey of a hundred and seventy miles from Unalachleet, they struck the Yukon on the 10th of November, gliding down a high steep bank on to it. Hardly a patch of clear ice was to be seen, the snow covering the whole extent. Accumulations of hummocks had in many places been forced on the surface before the river had become thoroughly frozen, and the water was still open, running swiftly in a few isolated streaks. From bank to bank was not less than a mile, the stream flowing among several islands. As they sledged up the river the dreary expanse of snow made them almost forget they were on a sheet of ice; and, as it winds considerably, their course was often from bank to bank to cut off corners and bends. Many cliffs abutted on the stream, and islands of sombre green forest studded it in all directions. [Illustration: ASCENDING THE YUKON]