midnight
All around them lay a solemn silence broken only by the splash of a bullfrog leaping from a bank , the gurgle of some water snake or the solemn croak of a bittern fishing near by , followed by the flap of its wings as it flew away , alarmed by their approach . All of the boys were more or less impressed by this strange silence . It seemed as though some heavy weight were pressing down upon them . Toby even whispered to one of his mates that it could hardly be worse if they were passing through a country graveyard at midnight . At the same time , all of them being bright , wide-awake fellows , there were plenty of interesting things continually cropping up to arouse their interest as scouts . Every minute or so someone was calling attention to this or that thing , though never forgetting the need of caution . If at any time a voice was raised more than Elmer deemed wise , a single `` hist '' from his lips caused the speaker to moderate his tones instantly .