"Stand ready, boys. We attack at dawn!" The word passed in a whisper down the long line of the trench, where the American army boys crouched like so many khaki-clad ghosts, awaiting the command to go "over the top." "That will be in about fifteen minutes from now, I figure," murmured Frank Sheldon to his friend and comrade, Bart Raymond, as he glanced at the hands of his radio watch and then put it up to his ear to make sure that it had not stopped.