The light buggy whirled around a curve on two wheels in a manner to make Mary catch her breath. Tom gave a low whistle. Then as the runabout made the same curve, Tom saw that the road ahead was straight but narrow. On one side, the left, rose a high cliff of rock, and on the right hand was a deep gully, the road running along its very edge. “Oh, Tom, do you think you can catch him in time?” asked Mary anxiously. “There’s another curve, just ahead, and if the horse goes around that as fast as it is going now it will go over the edge and Mr. Jacks will be killed!” “I’ve got to get him before that happens,” declared Tom grimly. “The horse will never be born that can beat my runabout.” Not idly had Tom’s electric machine been called “the speediest car on the road,” and now it surely was speeding. Though the frantic horse did his best, it was naught against the power of the batteries concealed in Tom’s car, and in a few moments the young inventor was driving along the narrow road on even terms with the swaying carriage in which sat a white-faced man. He was sawing on the reins and trying by his voice to halt the horse, but without effect. “The curve is just ahead, Tom,” warned Mary. “All right,” he answered. “You take the wheel now. I’m going to stand up, reach over, and pull him into this car. Keep close to the face of the cliff—it’s our only chance!” A moment later Tom rose in his seat, and as his hands left the steering wheel Mary leaned over and took charge of guiding the car. Exerting all his strength, Tom caught hold of Mr. Jacks under the arms and fairly pulled him from his seat. Luckily the old man was frail and light, or Tom could not have done it. “Here! Here!” cried the frightened horseman. “What—what——” But the breath was fairly choked out of him as Tom hauled him into the runabout and jammed him down on the seat between Mary and himself. Then Tom grabbed the wheel, and put on the brakes with all his might, for the dangerous curve was just ahead. On sped the maddened horse, the buggy bouncing up off the uneven road. Just as the runabout slowed to a stop the mad animal swung around the curve. It did not make it, for its speed was too great, and a moment later Mary gave a cry of pity as the ill-fated brute shot over the edge of the cliff, dragging the light buggy with it. There was a rattle of gravel, a shower of stones, a weird cry from the horse, which must have sensed its doom, and then the end came. Down the precipitous cliff had plunged the animal, crashing to death on the rocks below amid the splinters of the little carriage. Up above on the road, close to the rocky face of the cliff, sat the three in the runabout—a trembling, aged man, a white-faced girl, and Tom Swift, flushed by his exertions. “Well—well,” stuttered Jason Jacks, when he could get his breath, “I guess I’ve had a narrow escape. My—my horse went over the cliff, didn’t he?” “I’m afraid he did,” answered Tom grimly.