three o'clock
`` It 's one o'clock , fellows , '' said Dick , after walking over to the lantern for a glimpse at his watch . `` Tom , Greg and I will stay up until three o'clock and be ready to jump out together at the first sign of anything happening . The rest of you turn in and get some sleep . We 'll call you at three o'clock and then take our turn at the pillow . '' `` You 'll call us , of course , if anything happens ? '' asked Dave . `` If another powder mill blows up , '' chuckled Tom , `` you wo n't need to be called .