He was carefully burning out the lock, and had no doubt in his mind that he would succeed, for the safe was an old-fashioned one.
No further word was exchanged for half an hour. The man with the blowpipe continued in his work, the other watching with silent interest, ready to play his part when the operation was sufficiently advanced.
At the end of half an hour the elder of the two wiped his streaming forehead with the back of his hand, for the heat which the flame gave back from the steel door was fairly trying.
“Why did you make such a row closing the door?” he asked. “You are not usually so careless, Calli.”
The other looked down at him in mild astonishment.
“I made no noise whatever, my dear George,” he said. “If you had been standing in the passage you could not have heard it; in fact, I closed the door as noiselessly as I opened it.”
The perspiring man on the ground smiled.
“That would be fairly noiseless,” he said.
“Why?” asked the other.
“Because I did not close it. You walked in after me.”
Something in the silence which greeted his words made him look up. There was a puzzled look upon his companion’s face.
“I opened the door with my own key,” said the younger man slowly.
“You opened—” The man called George frowned. “I do not understand you, Callidino. I left the door open, and you walked in after me; I went straight up the stairs, and you followed.”
Callidino looked at the other and shook his head.
“I opened the door myself with the key,” he said quietly. “If anybody came in after you—why, it is up to us, George, to see who it is.”
“You mean—?”
“I mean,” said the little Italian, “that it would be extremely awkward if there is a third gentleman present on this inconvenient occasion.”
“It would, indeed,” said the other.
“Why?”
Both men turned with a start, for the voice that asked the question without any trace of emotion was the voice of a third man, and he stood in the doorway screened from all possibility of observation from the window by the angle of the room.
He was dressed in an evening suit, and he carried a light overcoat across his arm.
What manner of man he was, and how he looked, they had no means of judging, for from his chin to his forehead his face was covered by a black mask.
“Please do not move,” he said, “and do not regard the revolver I am holding in the light of a menace. I merely carry it for self-defence, and you will admit that under the circumstances, and knowing the extreme delicacy of my position, I am fairly well justified in taking this precaution.”
George Wallis laughed a little under his breath.
“Sir,” he said, without shifting his position, “you may be a man after my own heart, but I shall know better when you have told me exactly what you want.”
“I want to learn,” said the stranger.
He stood there regarding the pair with obvious interest. The eyes which shone through the holes of the mask were alive and keen.
“Go on with your work, please,” he said. “I should hate to interrupt you.”
George Wallis picked up the blowpipe and addressed himself again to the safe door. He was a most adaptable man, and the situation in which he found himself nonplussed had yet to occur.
“Since,” he said, “it makes absolutely no difference as to whether I leave off or whether I go on, if you are a representative of law and order, I may as well go on, because if you are not a representative of those two admirable, excellent and necessary qualities I might at least save half the swag with you.”
“You may save the lot,” said the man sharply. “I do not wish to share the proceeds of your robbery, but I want to know how you do it—that is all.”
“You shall learn,” said George Wallis, that most notorious of burglars, “and at the hands of an expert, I beg you to believe.”
“That I know,” said the other calmly.
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 tonight because you brought your gas with you this morning. You were waiting in the dark hallway 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
