half past nine
By their calculation , and allowing for a head wind , they had concluded that they would have covered the three hundred miles by ten o'clock . If at that time they could make out no signal light , they had decided to come down on the upland and go into camp for the night . Their calculation was purely a guess but it was not a bad one . Some time after half past nine both boys made out in the far eastern sky a soft glow . `` I thought it had to be a clear night for the Aurora Borealis , '' suggested Roy , conscious that his companion had also seen the same glow . For a time Norman made no response but he headed the machine directly toward the peculiar flare and ceased his tacking . `` That 's no Aurora , '' he said at last .