When we started next morning the thermometer stood at 45° below zero, but we were out of the wind region and did not mind the cold. It is curious that a few miles on either side of that Gap the air will be still, while in the Gap itself a gale is blowing. Seven times I have passed through that Gap and only once without wind. The great Flats were now behind us, we had passed into the mountains, and for the remainder of our long journey we should scarce ever be out of sight of mountains again. Up the river, with its constant trouble of overflow, going around the open water whenever we could, plunging through it in our mukluks when it could not be avoided--with the care of the dogs' feet that the cold weather rendered more than ever necessary when they got wet, and the added nuisance of throwing the toboggans on their sides and beating the ice from them with the flat of the axe wherever water had been passed through--for two days we followed its windings, the thermometer between -45° and -50°, the mountains rising higher and the scenery growing more picturesque as we advanced. At the end of the second day from the Gap we were at the mouth of the West Fork of the Chandalar, and after passing up it for fifteen or sixteen miles we left that watercourse to cross the mountains to the South Fork of the Koyukuk River. Then began hard labour again. A toboggan is not a good vehicle for crossing summits. Its bottom is perfectly flat and smooth, polished like glass by the friction of the snow. If the trail be at all "sidling" (and mountain trails are almost always "sidling"), the toboggan swings off on the side of the inclination and must be kept on the trail by main force. The runners of a sled will grip the surface, if there be any inequalities at all, but a toboggan swings now this way and now that, like a great pendulum, dragging the near dogs with it. Again and again we had to hitch both teams to one toboggan to get up a sidling pitch while all hands kept the vehicle on the trail, and our progress was painful and slow. In soft snow on a level surface like the river bed or through the Flat country, generally, the toboggan is much the more convenient vehicle, for it rides over the snow instead of ploughing through it, but on hard snow anywhere or on grades the toboggan is a nuisance. Thus wallowing through the deep snow at the side of the toboggans to hold them in place we sweated and slaved our way mile after mile up the gradual ascent until we reached the spot, just under a shoulder of the summit, where there was dry spruce and green spruce for camping, the dry for fire and the green for couch, and there we halted for the night. [Sidenote: JOHN MUIR]