six in the
evening
But when Denman sought the deck after breakfast , it had stopped ; and he saw Munson , still haggard of face , talking to Jenkins at the hatch . `` Got his wave length now , '' Denman heard him say . `` Took all night , but that and the code 'll fool 'em all . '' From then on Munson stood watch at his instrument only from six in the evening until midnight , got more sleep thereby , and soon the tired , haggard look left his face , and it resumed its normal expression of intelligence and cheerfulness . After supper about a week later , Denman and Florrie sat in the deck chairs , watching the twilight give way to the gloom of the evening , and speculating in a desultory manner on the end of this never-ending voyage , when Munson again darted on deck , and ran up the bridge stairs with a sheet of paper , barely discernible in the gathering darkness , and handed it to Jenkins , who peered over it in the glow from the binnacle . Then Jenkins blew on a boatswain 's whistle -- the shrill , trilling , and penetrating call that rouses all hands in the morning , but is seldom given again throughout the day except in emergencies . All hands responded .