Lightning flickered on the sea, touching the back of the smooth swell, and then for a few moments left all very dark. The moon was new, the sky was cloudy, and the swell ran high, for it rolled, unbroken and gathering momentum, from the Antarctic ice. When the lightning was bright, one saw a low cloud that looked like steam, with a white streak beneath that marked the impact of the big rollers on the sandy coast. The crash of breakers came out of the dark, like the rattle of a goods train crossing an iron bridge.
"Four fathoms at spring tides, and a shifting channel!" Brown remarked, quoting from a pilot-book. "The depth, however, varies with the wind, and a stranger must use caution when entering the lagoon." He stopped, and laughed as he resumed: "If this was a sober undertaking I'd steam off and wait for daylight."
"I reckon it would be prudent," said Lister dryly.
"We have nothing to do with prudence," Brown rejoined. "Our job's to work in a sun that knocks a white man down, and stew in the hot malaria damp the land breeze brings off at night. Cartwright's orders are to lose no time and I want to finish before the fever finishes me. Very well! When the moon is new, high-water's at twelve o'clock, and along this coast sunset's about six hours later. If we wait for noon-to-morrow, it will be four or five o'clock before we get on board the wreck—I understand the tide doesn't leave her until about four hours' ebb. If we push across the bar to-night, we'll see her at daybreak and can make our plans for getting to work."
Lister agreed. Expenses were heavy and it was important they should not lose a day. Moreover, Cartwright had hinted that he expected them to run risks, and Lister had promised Barbara to help him out. If Brown touched bottom steaming in, tug and barge would soon break up; but Lister was not going to be daunted.
"I'll go down and raise some extra steam," he said. "You'll need full pressure to shove her through the surf."
He was occupied for some time, but when a plume of steam blew from the escape-pipe he came up to the door and looked about. Terrier's languid roll was getting sharper; mast and funnel swung into a wide sweep. Sometimes the dark hull lurched up high above the tug's stern, and sometimes sank in a hollow. The rollers had angry white tops, and a belt of filmy vapor that looked luminous closed the view ahead. Lister knew the vapor was phosphorescent spray, flung up by the turmoil on the bar, through which they must go. If the tug struck and stopped, the white seas would beat her down into the sand. In the meantime, she was using full steam, because, since tide and surf carried her on, one must have speed to steer.
The spray cloud got thick, and wavered with luminous tremblings when the long rollers broke. They came up, spangled with green and gold flashes, from astern, shook their fiery crests about the tug, and vanished ahead, but one heard them crash. Lister thought the tug throbbed to the savage concussion. He could not hear his engines; one heard nothing but the daunting uproar.
By and by he felt a shock; not a violent shock, but as if the boat had touched, and was pushing through, something soft. She slowed and Lister saw the black hulk swing up and ride forward on a giant roller's top. It looked as if she were coming on board the tug, and Lister jumped through and slammed the iron door. Brown would need him now.
He heard the roar of water on deck, there was a crash of broken glass, and a shower fell on his head. A cloud of steam and a loud hissing came from the stokehold, and he knew the sea that swept the tug had covered the gratings. If she stuck, the next sea would swamp her and drown the fires, but she had not altogether stopped. The propeller was beating hard and he opened the throttle wide. He felt her move and tremble, as if she struggled in the grip of the sand, and then lift buoyantly. The water that pressed her down had rolled off the deck and the oncoming comber had picked her up and was carrying her along.