Wallis went on with his task apparently undisturbed by this extraordinary interruption. The little Italian’s hands had twitched nervously, and here might have been trouble, but the strength of the other man, who was evidently the leader of the two, and his self-possession had heartened his companion to accept whatever consequences the presence of this man might threaten. It was the masked stranger who broke the silence. “Isn’t it an extraordinary thing,” he said, “that whilst technical schools exist for teaching every kind of trade, art and craft, there is none which engage in teaching the art of destruction. Believe me, I am very grateful that I have had this opportunity of sitting at the feet of a master.” His voice was not unpleasant, but there was a certain hardness which was not in harmony with the flippant tone he adopted. The man on the floor went on with his work for a little while, then he said without turning his head-- “I am anxious to know exactly how you got in.” “I followed close behind you,” said the masked man. “I knew there would be a reasonable interval between the two of you. You see,” he went on, “you have been watching this office for the greater part of a week; one of you has been on duty practically every night. You rented a small office higher up this street which offered a view of these premises. I gathered that you had chosen to-night because you brought your gas with you this morning. You were waiting in the dark hall-way of the building in which your office is situated, one of you watching for the light to go out and Mr. Gilderheim depart. When he had gone, you, sir”--he addressed the man on the floor--“came out immediately, your companion did not follow so soon. Moreover, he stopped to pick up a small bundle of letters which had apparently been dropped by some careless person, and since these letters included two sealed packets such as the merchants of Hatton Garden send to their clients, I was able to escape the observation of the second man and keep reasonably close to you.” Callidino laughed softly. “That is true,” he said, with a nod to the man on the floor. “It was very clever. I suppose you dropped the packet?” The masked man inclined his head. “Please go on,” he said, “do not let me interrupt you.” “What is going to happen when I have finished?” asked George, still keeping his face to the safe. “As far as I am concerned, nothing. Just as soon as you have got through your work, and have extracted whatever booty there is to be extracted, I shall retire.” “You want your share, I suppose?” “Not at all,” said the other calmly. “I do not want my share by any means. I am not entitled to it. My position in society prevents me from going farther down the slippery path than to connive at your larceny.” “Felony,” corrected the man on the floor. “Felony,” agreed the other.