the hour of nine
'' _ Bong-g-g ! Bong-g-g ! Bong-g-g ! -- _ '' With a hollow booming sound reminiscent of old eighteenth-and nineteenth-century clock towers , the electronic time tone rang out from the Tower of Galileo , chiming the hour of nine . As the notes reverberated over the vast expanse of Space Academy , U.S.A. , the lights in the windows of the cadet dormitories began to wink out and the slidewalks that crisscrossed the campus , connecting the various buildings , rumbled to a halt . When the last mournful note had rolled away to die in the distant hills , the school was dark and still . The only movement to be seen was the slow pacing of the cadet watch officers , patrolling their beats ; the only sound , the measured clicking of their boots on the metal strips of the slidewalks .