twelve o'clock
The latter kicked until he kicked the pack from his back . Amid the shouts of laughter of his companions , his face red and perspiring , Ned was obliged to gather up the pack in sections and strap it in place again , which he did after much endeavor . Thereafter he kept his temper . `` I 've heard it said that a mule would n't kick after twelve o'clock , '' said Chunky . `` Guess it was n't true . '' `` Perhaps it is after twelve o'clock at night that was meant , '' suggested Tad . `` Mules are asleep then , are n't they ? ''