ten o'clock
She merely wondered why , for the first time in his life , Lad should absent himself at dinnertime from his time-honored place on the dining-room floor , at the Master 's left . And , amusedly , she recalled what her husband had said of the stately dog 's new propensity for mischief . Perhaps Lad was exploring the friendly home-woods in search of a bear ! But when ten o'clock came and Lad did not seek the shelter of his `` cave '' under the music-room piano , for the night , there was real worry . The Mistress went out on the veranda and sounded long and shrilly upon the silver whistle which hung from her belt . From puppyhood , Laddie had always come , at a sweeping gallop , on sound of this whistle . Its notes could travel , through still air , for a half mile or more .