Over there on the shore, in a clump of flowering, semi-tropical bushes, crouched two men. On the ground with them lay a metal cylinder some two feet long and seven inches in diameter. There was also a coil of wire and a boxed magneto battery.
One of the pair held to his eyes a pair of night marine glasses.
Incessantly this watcher kept his gaze focused on Williamson.
About two o'clock in the morning Williamson found it necessary to go below for a few moments. After reaching the conning tower he paused, for a few moments, to look keenly all about him.
Yet, look as he would through the night, the machinist's vision could not see that the bush hidden pair on shore, guessing his intention from his stop by the conning tower, had silently taken to the water. With them they towed the metal cylinder, which floated. To the cylinder was attached one end of the light wire.
Some distance out from the shore the pair halted, treading water, only their eyes above the surface. But Williamson could not make out such small objects at the distance. Then he went below.
"Now, for it," breathed one of the swimming pair, tensely.
Both swimmers struck out strongly, yet silently, making fast progress through the water by means of some of the best strokes known to swimmers.
When they reached the port side of the submarine Williamson was still below. Nor had the attention of the marine guard on the "Waverly" been attracted.
In just another swift instant the swimmers made a dive that carried them and their cylinder below the surface.
Straight up against the bottom of the hull the pair went.