four o'clock in the morning
Chevalier spoke to him : `` You 've no collar . You are not happy . Poor fellow , I ca n't do anything for you . '' By four o'clock in the morning he found himself in the Avenue de l'Observatoire . On seeing the houses of the Boulevard Saint-Michel he experienced a painful impression and abruptly turned back toward the Observatory . The dog had vanished . Near the monument of the Lion of Belfort , Chevalier stopped in front of a deep trench which cut the road in two .