ten o'clock
A strayed Indian from Lake Le Barge was willing to take his place ; but Kama was obdurate . He grunted with a slight intonation of resentment , and that was all . The dogs , however , Daylight changed , leaving his own exhausted team to rest up against his return , while he went on with six fresh dogs . They travelled till ten o'clock the night they reached Selkirk , and at six next morning they plunged ahead into the next stretch of wilderness of nearly five hundred miles that lay between Selkirk and Dyea . A second cold snap came on , but cold or warm it was all the same , an unbroken trail . When the thermometer went down to fifty below , it was even harder to travel , for at that low temperature the hard frost-crystals were more like sand-grains in the resistance they offered to the sled runners . The dogs had to pull harder than over the same snow at twenty or thirty below zero .