The second mistake was in engaging a boy as guide instead of a man. He was an attractive youth of about fourteen who had done good service at the Circle City mission the previous winter, when our nurse-in-charge was contending single-handed against an epidemic of diphtheria. He was a pleasant boy, with some English, who wanted to go and professed knowledge of the route. The greatest mistake of all was starting out through that lonely waste with the thermometer at 52° below zero. The old-timers in Alaska have a saying that "travelling at 50° below is all right as long as it's all right." If there be a good trail, if there be convenient stopping-places, if nothing go wrong, one may travel without special risk and with no extraordinary discomfort at 50° below zero and a good deal lower. I have since that time made a short day's run at 62° below, and once travelled for two or three hours on a stretch at 65° below. But there is always more or less chance in travelling at low temperatures, because a very small thing may necessitate a stop, and a stop may turn into a serious thing. At such temperatures one must keep going. No amount of clothing that it is possible to wear on the trail will keep one warm while standing still. For dogs and men alike, constant brisk motion is necessary; for dogs as well as men--even though dogs will sleep outdoors in such cold without harm--for they cannot take as good care of themselves in the harness as they can when loose. A trace that needs mending, a broken buckle, a snow-shoe string that must be replaced, may chill one so that it is impossible to recover one's warmth again. The bare hand cannot be exposed for many seconds without beginning to freeze; it is dangerous to breathe the air into the lungs for any length of time without a muffler over the mouth. Our troubles began as soon as we started. The trail was a narrow, winding toboggan track of sixteen or seventeen inches, while our sled was twenty inches wide, so that one runner was always dragging in the loose snow, and that meant slow, heavy going. [Sidenote: SUNRISE AND SUNSET]