The sudden formulation of the escape plan had been too quick for even the Mercurian brains to block. Terry and Cappy were racing into the forest of ferns far ahead of their pursuers. The coordinated muscles of the earthmen were far more capable of traveling swiftly than those of the Mercurians behind and sounds of pursuit grew fainter in the distance.
But Terry knew that these creatures were dogged. They would follow until the spaceship's rockets blasted loose from the planet.
"Remember," Terry whispered, "don't act on any set plan. Don't plan what you'll do when you meet 'em. If you do they'll be prepared for it. Act on impulse, before they know what you intend to do."
"I'll remember," Cappy panted.
Was it impulse that made terrestrials the masters of the universe? Terry wondered. It hardly seemed logical, yet impulse had given them their first chance of freedom. But impulse might lead them astray. First thoughts are not always the best thoughts. True enough, man had made some strides by accident, but far more of his greatest discoveries and most useful inventions had been the result of years of labor and careful planning. No, it wasn't impulse. Some other weapon had to be used to defeat the Mercurians decisively. Terry and Cappy might escape through luck, but some day there would be a final, decisive battle that would employ the one thing that gave man an advantage over the semi-human monsters of the first planet.
Terry hoped he could discover that weapon now.
They had been over the route to the spaceship three times. Once in company with Chomby on their first trip to the Mercurian village. They had returned in company with a guard and come back again later.
Terry had noted a few landmarks and now he began to spot them again. A curious-shaped rock; a spring of moulten metal; a deep fissure in the soil.
But as they traveled toward the sun's corona the air grew warmer. Vegetation became profuse and the trail was more difficult to find. But Cappy had kept his eyes open, too. Between them they made their way, slower and slower.