about eleven o'clock
`` We simply must get out of this before night or we are lost . '' `` You forget about the length of the days up here at this time of the year , '' reminded Tad with a faint smile . `` That 's so , '' agreed Rector . `` You know it does n't get really dark until about eleven o'clock to-night . So you see we have plenty of time in which to get that pack and reach a camping place before the night gets too dark for us to see what we are about . '' Tad stepped to the edge of the trail and looked over the dead mule and the pack lashed to him . He saw that the pack already had slipped dangerously , and that a sudden jolt might send it hurtling into the chasm .