For a scant ten minutes longer Howard held on, now very close beneath the mantle of weed, then stopped altogether, and waited for the reserve buoyancy of the Seashark to carry her upward.
Slowly she rose again, and then into the weed. Howard could see its slimy fronds through the thick glass of the conning-tower. Slowly and more slowly it seemed to brush downward as the Seashark worked herself upward. Slowly and more slowly until all motion ceased, leaving the vessel still far below the surface.
With a shrug of his shoulders, Howard pulled a lever, and in quick response came the throb of the pumps beneath him as with powerful strokes they drove out the water-ballast and made the Seashark lighter.
Under this new impulse she rose once more, little by little, until at last the pumps sucked dry and motion ceased once more. Howard, peering upward, saw the light faintly gleaming through the interstices of the weed. The surface could be scarcely a yard overhead.
“Only a yard.” Howard muttered the words bitterly. “Only a yard! Might as well be a thousand!” Gently he started the propeller; half a dozen revolutions he knew would hopelessly foul it; but little difference that would make if the Seashark could work her way upward by its aid. Now forward, now backward he drove it, with his heart in his mouth.
Not for long, for the drag on the shaft soon warned him that to go on would shatter the machinery and, even if they reached the surface, leave them helpless far within the bounds of the weedy sea. With a sudden impulse he stopped the engine, and waited to see whether time might not do what machinery had failed to accomplish.
Half an hour passed, and the same frond of weed that had lain across his view at its beginning still held its place. The Seashark was stationary.
One desperate recourse remained, and Howard prepared to take it. He swung down into the cabin where sat the rest of the party forlornly waiting. Long before they had realized that something was desperately wrong; but none of them, except perhaps the missionary, were of the weak-kneed type, and none had moved to question Howard, even during the age-long interval when he had sat in silence.
Howard looked at them one by one, his eyes lingering fondly on Dorothy’s flower-like face. “Friends all,” he said, quietly, “our situation is most serious. I knew when we dived that in about four hours we must come to the surface to run our gas-engine and recharge our electric batteries. I hoped and believed that in four hours we would come to a place where there were breaks in the weed, or where it was so thin that we could rise through it. Neither has turned out to be true. There are no breaks, and the weed is so thick that it holds us down. I have expelled all the water-ballast, and the Seashark is now very buoyant; yet it cannot rise to the surface. We are scarcely a foot below it, but we can rise no higher.
“The explanation is evident. The Seashark is nearly fifty feet long. Probably she intercepted a score of cables of weed as she rose. No doubt there is now a whaleback of sargassum standing above the water just over her. Its weight must be very great—too great for even our increased buoyancy to lift farther; while the cables across us prevent the weed from slipping off. The only way to get to the surface—that is to say, the only way to save all our lives, is to cut away the cables that hold us down.”