Nor had he any clear idea how long it would take to slow down to a vertical drop. Able Jake made a full half swing of the globe to brake down but Able Jake was an ultra-streamlined object with many times the mass and weight of Johnny and his rig; furthermore the ships were controllable to a certain degree while Johnny was not. Beyond the certain knowledge that the effect of the chutes would be quite violent and probably short-lived, the rest was unpredictable. He tried to shake off gloomy speculation, uneasily aware that much of the carefree confidence of the last hour had deserted him. In a more normal state of mind again he became prey to tension once more, a pounding heart and dry mouth recalling mercilessly the essential frailties of his kind. So, with aching neck and burning eyes he strained for a clear view past the length of the cylinder and-- There! The preliminary to the visual changes, a sudden sweep of distortion over the landscape as his angle of sight through the refracting particles became more shallow. Now was the time he had judged the throat vane gyros should begin their run-up. He worked the lanyard back carefully, fearful an awkward movement might upset the cylinder's line-up, pulling the trigger lever over to half-cock where the micro switch should complete circuit with the dry power pack. There should be approximately one minute before the major color changes began, which was also the minimum time for gyro run up. Johnny resumed the watching and the waiting. How long is a minute? Is it the time it takes the fear-frozen trainee, staring glass-eyed at the fumbled grenade to realize that this one at his feet is a dud? Or is it the time before the rock-climber, clinging nail and toe to the rock face with the rope snapped suddenly taut, feels it at last slacken and sees the hands gripping safely come into sight? Perhaps the greenhorn, rifle a-waver, watching the glimpse of tawny color in the veldt-grass and waiting the thunder and the charge, could say. They'd all be wrong. It's much longer. Long enough for Johnny to think of a dozen precautions he could have taken, a dozen better ways to rig this or that. Long enough to worry about whether the gyros were really running up as they should. A thousand queries and doubts piled mountainously upward to an almost unbearable peak of tension till suddenly the browns and greens below flashed a shade lighter and it was time, and the savage snap on the lanyard a blessed relief and total committal. * * * * * In the few seconds after the firing of the prime and before the busy little timer snapped the valves wide open Johnny managed to slip his toes under the jet pedals to avoid accidental firing. At the same time he braced himself as rigidly as possible with aching arms against the walls of the cylinder.