Acting on this law of nature, Professor Roumann had, with the aid of Mr. Henderson, constructed a machine which, when a negative current of electricity was sent into it, would force away any object that was approaching the _Annihilator_. In a few moments the boys at the Cardite motor heard the hum, the throb and crackling that told them that the repelling apparatus was at work. But would it act in time? Or would the meteor prove too powerful for it? And, if it did, would the two scientists be able to steer the swiftly moving projectile out of the way of the big, black stone, as the old hunter called it? These were questions that showed on the faces of the two lads as they bent over the motor. "We're only going fifty miles a second now," whispered Jack. Mark nodded his head. "Can't you pull the lever over faster?" he asked. "I don't dare," replied his chum. There was nothing to do but to wait and gradually slow up the projectile as much as possible. The boys could hear the professors in the pilothouse shifting gears, valves and levers to change the course of the projectile. Andy Sudds and Washington White, with fear on their faces, looked into the engine room, waiting anxiously for the outcome. "Hab--hab we hit it yet?" asked Washington, moving his hands nervously. "I reckon not, or we'd know it," said the hunter. "No, not yet," answered Jack, in a low voice. "How much are we making now, Mark?" "Only thirty a second." "Good! She's coming down." Hardly had he spoken than there sounded a noise like thunder, or the rushing of some mighty wind. The projectile, which was trembling throughout her length from the force of the motor, shivered as though she had plunged into the unknown depths of some mighty sea. The roaring increased. Mark and Jack looked at each other. Washington White fell upon his knees and began praying in a loud voice. Old Andy grasped his gun, as though to say that, even though on the brink of eternity, he was ready. Then, with a scream as of some gigantic shell from a thousand-inch rifle, something passed over the _Annihilator_; something that shook the great projectile like a leaf in the wind. And then the scream died away, and there was silence. For a moment no one spoke, and then Jack whispered hoarsely: "We've passed it." "Yes," added Mark, "we're safe now." "By golly! I knowed we would!" fairly yelled Washington, leaping to his feet. "I knowed dat no old meteor could kerflumox us! Perfesser Henderson he done jumped our boat ober it laik a hunter jumps his boss ober a fence. Golly! I'se feelin' better now!" "How did you avoid it?" asked Mark of the professor. "With the help of the repelling machine and by changing our course. But we did it only just in time. It was an immense meteor, much larger than at first appeared, and it was blazing hot. Had it struck us, there would have been nothing left of us or the projectile either but star dust. But we managed to pass beneath it, and now we are safe."