Bohannan slid the window shut and settled himself beside Captain Alden. He glanced at his wrist-watch, and a thrill of nervous exultation stabbed him. "Only two minutes and six seconds more!" he murmured, gnawing at his mustache and blinking with excitement. Alden remained calm, impassive as the Master himself, who now, pressing another button, sent a beam of wonderful, white light lancing through the darkness. Track, buildings, trees all leaped into vivid relief as he tested the searchlight control. He shot the beam up, up, till it lost itself, vaguely, in mist and cloud; then flung it even across the river, where it picked out buildings with startling detail. He turned it, finally, square down the launching-way, through the yawning gates where the track abruptly ended at the brow of the Palisades--the empty chasm where, if all went right and no mistake had been made in build, engine-power, or control, the initial leap of _Nissr Arrib ela Sema_ was to be made. Came a moment's wait. Faintly the pulsing of the engines trembled the fabric of _Nissr_. Finely balanced as they were, they still communicated some slight vibration to the ship. The Master snicked the switch of the magnetic-anchor release; and now the last bond that held _Nissr_ to her cradle was broken. As soon as the air-skid currents should be set going, she would be ready for her flight. This moment was not long in coming. Another turn of a switch, and all at once, far below, a faint, continuous hissing made itself audible. Compressed air, forced through thousands of holes at the bottom of the floats, was interposing a gaseous cushion between those floats and the track, just as it could do between them and the earth wherever _Nissr_ should alight. Suspended thus on a thin layer of air, perhaps no more than a sixteenth of an inch thick but infinitely less friction-producing than the finest ball-bearing wheels and quite incapable of being broken, the ship now waited only the application of the power in her vast propellers. "Let in numbers two and four," commanded the Master, suddenly, into the engine-room telephone. "In five seconds after we start, hook up one and three; and five later, the other two." "Aye, aye, sir," came back the voice of Auchincloss, chief engineer. "Ready, sir!" Almost at once, the vibration of the engines altered, grew more marked, seemed to be taking hold of something with strong but easy effort. Another trembling made itself felt, as two of the giant screws, connected by reducing-gears with the engine-shafting--all three engines being geared to one shaft, but any one being capable of separate running--began to revolve. From astern, a dull, droning hum mounted, rose, grew rapidly in volume and power. And, as two more screws began to whirl, the Eagle of the Sky shook herself slightly. She awoke from slumber. Steadily, smoothly on her air-cushions she began to move forward down the long, sloping trackway to the brink of the cliff.