"Putting on the sand," replied Jack, as he kicked at the plunger which, being depressed, let a stream of fine gravel out on the rails. "The wheels are gripped I think, and are slipping on the rails. This may help some." "Let me give you a hand," exclaimed a voice, and the boys turned to see the shabby man standing with them on the platform. He grasped the brake handle, and gave it an additional turn. His strength seemed remarkable for so small a man. The speed of the car was checked a little, but the vehicle was still speeding along at a rate that would soon bring it to destruction if not halted before the curve was reached. "That's a little better," observed Mark. "It's a good thing you were here." "Good for me, not so good for you," said the man with a peculiar smile. "What do you mean?" asked Mark. "I mean that I shall have to place you under arrest for attempting to assassinate Lord Peckham!" exclaimed the man. "I am Detective Ducket, of Scotland Yard!" He stripped off a false beard he had donned, and threw back his coat, displaying his shield. He was the same man who had attempted to arrest the boys in the police station at Easton. "I've got you just where I want you now," Detective Ducket went on. "There are none of those blooming American police to interfere." The next instant the car gave a sudden lurch. Then it seemed to rise up in the air. Jack felt himself flying through space, and he observed Mark, who was clinging to the valise, following him. There was a terrific crash, a ripping, tearing splintering sound, and the runaway trolley smashed into a big oak tree at the foot of the hill. The vehicle had completely jumped the track at the sharp curve. Jack's eyes grew dim, and he seemed to be sinking down in some dark pool of water. He heard a splashing beside him and began to strike out, trying to swim. He seemed to be choking. Then the blessed air and daylight came to him, and he found he was floating on the surface of a pond. He dashed the water from his eyes and saw, over on the bank, the wreck of the trolley. Then he noticed that Mark was swimming beside him. "What happened?" asked Jack. "A little of everything," panted Mark. "Lucky we weren't killed. We must have been flung off the rear platform into this duck pond." The boys soon made their way to shore, unhurt except for the wetting. The fall into the water had saved their lives. "Where's the valise of machinery?" asked Jack. "There it is," answered Mark pointing to where it had fallen at the back of the pond. "And what became of Detective Ducket?" "He's here, at your service!" exclaimed a voice. "Consider yourselves under arrest and don't you dare to leave this place without me." The boys looked in the direction of the sound and saw the English officer lying on the grass not far away. He seemed in pain, but had raised himself on his elbow and was pointing his finger sternly at the boys. CHAPTER VII OFF FOR THE SOUTH POLE "Are you hurt?" asked Jack.