one o’clock in the morning
`` The call of suffering humanity , Petrie , is one which I may no more refuse to hear than you . '' I made no further protest after that , for his point of view was evident and his determination adamant , but told him where he would find the bag and once more set out across the moonbright common , he pursuing a westerly direction and I going east . Some three hundred yards I had gone , I suppose , and my brain had been very active the while , when something occurred to me which placed a new complexion upon this second summons . I thought of the falsity of the first , of the improbability of even the most hardened practical joker practising his wiles at one o'clock in the morning . I thought of our recent conversation ; above all I thought of the girl who had delivered the message to Eltham , the girl whom he had described as a French maid -- whose personal charm had so completely enlisted his sympathies . Now , to this train of thought came a new one , and , adding it , my suspicion became almost a certainty . I remembered -LRB- as , knowing the district , I should have remembered before -RRB- that there was no number 280 in Rectory Grove .