“I declare!” he finally exclaimed. “Perhaps you are right, Harry. Those whiskers did not look really natural.” “No, nor are they. I tell you that fellow is Van!” Old King Brady strode up and down the room for some time. “Well,” he said, finally, “what ought we to do?” “I see only one plan.” “What?” “Arrest him!” “Of course! We could have done it at the hotel desk.” “But we did not know him.” “That is it.” “He is very likely in his room just now. Let us work the surprise on him. Fate seems to have played this into our hands.” The Bradys were elated. Their luck in having probed the fellow’s disguise seemed likely to stand them in good stead. But they knew better than to act too openly. “Harry,” said Old King Brady, “we must proceed with due caution. You can slip out now and get an officer.” “Yes.” “I will go down and look on the register and get the number of his room.” “Very well.” “Then I will meet you at the Tremont street door. Do you see?” “Yes.” “Very good. The officer can go right up to his room. I will go up one corridor and you the other. Then we have him trapped.” “Splendid!” The detectives had laid their plan well. As a matter of fact, their surmises were correct. Martin Van was in his room. He did not dream, of course, that the Bradys had penetrated his disguise. It was his purpose to follow them like a lynx and at a favorable moment strike one or both down with his own hand. The officer secured by Harry carried out his part of the programme. He proceeded to the door of Van’s room and rapped. At first there was no answer. Then a movement in the room was heard and a voice said: “Who is it?” “A friend on business!” “What is the name?” “Open the door and you will see!” Silence ensued and the officer rapped again. “Wait a moment!” said the occupant of the room. That was the last answer. The officer suddenly put his shoulder to the door and forced it in. The Bradys came rushing up the corridor expecting trouble. But there was none. The reason was evident. The room was empty. A window opening upon a fire-escape was open. It was by means of this that Van had escaped. “Quick!” cried Harry. “We must cut him off below.” Downstairs dashed the detectives. As they reached the sidewalk they saw a man in a big overcoat turn the corner below into Washington street. It was Van. The detectives rushed after him. In the crowd, however, they lost track of their man. Much chagrined, however, the detectives would not give up. They went on at random. Suddenly leaving Haymarket Square they turned into Portland street. This is the street of livery stables. From the door of one of these stables they saw a cutter sleigh drawn by a spirited horse emerge. One man sat in the sleigh. “Great Scott!” exclaimed Harry. “Is not that Van?” The same big overcoat and hat betokened that it was the crook. He looked back once and saw the Bradys. His whiskers had been sacrificed. It was easy to recognize him.