As the dust was left behind, he saw a dim figure standing by the bridge. Then he remembered what Penny had said about Hawley dropping one of his passengers at that point, and a sudden fear shot through Matt's nerves. The man waved his hand, ducked downward and disappeared under the canal. In the space of a breath, almost, he reappeared and dashed back toward the roadside. Then on Matt's startled ears there burst the dull _boom_ of an explosion. Under his eyes the bridge seemed to rise up and drop back into the canal. Matt slowed down, his heart in his throat and his nerves in rags. Hawley had left that man behind to blow up the bridge, well knowing that Matt could not pass the chasm on his motor-cycle, and that the nearest bridge he could reach was miles away. The whirr of the car behind him grew loud and louder in his ears, and above it came yells of triumph. Dazed and feeling himself all but beaten, Matt nevertheless continued on toward the wrecked bridge. The next moment he saw something that aroused his hopes. One stringer was left, spanning the gulf from bank to bank--a square timber that offered possibilities, albeit dangerous ones. A nail in the stringer would mean a bursted tire! Even a sliver might cause damage that would stop the _Comet's_ flight. Gritting his teeth Matt speeded up the machine, tore down the slope and took the end of the timber at a bound. The motor-car was close and he dared not look behind him. Every faculty had to be centered upon that narrow, dangerous path over which he was rushing at perilous speed. He could not see what the cowboy was doing, nor know how a scant forty feet of rope fell short, for the cowboy, past master at throwing the lariat, had leaned forward over the long bonnet and made a cast. "A thousand dollars if you stop that boy!" Motor Matt heard this yelled fiercely in Hawley's voice, and behind him the noose fell short! If there were nails or slivers in that square timber, the rubber tires missed them. Matt gained the opposite side of the canal and sped up the bridge approach. The man who had set off the explosion leaped into the road, swinging his arms and shouting; then very suddenly he leaped out again, for the hundred-and-fifty-pound motor-cycle was coming toward him at deadly speed. Matt was abreast of the man and beyond him in the space of a heart-beat, and he stole a quick look behind. Dirk Hawley had overreached himself. His evil machinations had resulted in destroying the bridge, but he had foiled himself and not the daring youngster who had taken a bold risk and crossed the gap. The motor-car was at a dead stop on the other side of the canal, and a baffled group of three surrounded it and called wild words to the man on the other side. A loud laugh escaped Matt's lips and dwindled behind him in a mere wisp of sound. He was safe! Now his race was against time alone.