Ahead of them lay that track of dazzling light. Every fragment of timber used in the construction of the inclined trestle upon which the seaplane was expected to reach the water was as plainly visible as at midday, with the sun shining above.
Billy fairly held his breath in fear lest the swift rush of the hydro-aëroplane should catch the two men on the slope unprepared, and hurl them into space. Just in the nick of time they threw themselves to one side, and the plunging monster glided by, so close that had he so willed, Billy could have thrust out a hand and touched one of the shrinking figures.
Then came a tremendous splash as they struck the water. Frank had made his calculations so carefully that there was not the slightest danger of a mishap. The boat was descending at such an angle that it instantly shot off the wheels that were underneath, and skimmed along the surface of the water like a great duck.
Billy drew his breath again, for it seemed as though they had actually run the gauntlet in safety. He heard the familiar throb of the reliable motors beginning to take up their sweet song, which told that Frank had started the machinery at the proper second, so that they did not lose any of the impetus gained in that rush down the slope.
From up in the quarter where they knew the hangar must be, came loud cries of anger. Those who had planned to capture the seaplane when it was in prime condition for a flight to the German lines had evidently met with a most aggravating disappointment.
Suddenly the brilliant light vanished, shutting them in a pall of darkness that was all the more dense because of their having been staring into that illuminated avenue ahead, along which the seaplane was rushing at fair speed.
"It's all clear in front, Billy," Frank hastened to say, knowing that his companion must naturally think of the danger of a collision the first thing.
"Listen to 'em growl!" chuckled Billy, who had evidently been greatly amused as well as interested in the remarkable dash of the _Sea Eagle_. "But, after all, that was what I'd call a close shave, Frank. Didn't you hear the door being smashed in as we started?"
"I thought I did," replied the other, "but I knew that nothing up there could give us any trouble. The only chance of our being wrecked was for those on the inclined plane to place some obstruction on the track that would throw the wheels of our carriage off, and dump us in a heap below."