All night this was kept up, and when morning came, though only the clocks told it, for eternal night was below the surface, the rival gold-seekers were still on the trail.
"They won't give up," declared Mr. Swift hopelessly.
"No, we've got to race them for it, just as Berg proposed," admitted Tom. "But if they want a straightaway race we'll give it to 'em. Let's run her to the limit, dad."
"That's what we've been doing, Tom."
"No, not exactly, for we've been submerged a little too much to get the best speed out of our craft. Let's go a little nearer the surface, and give them the best race they'll ever have."
Then the race began; and such a contest of speed as it was! With her propellers working to the limit, and every volt of electricity that was available forced into the forward and aft plates, the Advance surged through the water, about ten feet below the surface. But the Wonder kept after her, giving her knot for knot. The course of the leading submarine was easy to trace now, in the morning light which penetrated ten feet down.
"No use," remarked Tom again, when, after two hours, the Wonder was still close behind them. "Our only chance is that they may have a breakdown."
"Or run out of air, or something like that," added Captain Weston. "They are crowding us pretty close. I had no idea they could keep up this speed. If they don't look out," he went on as he looked from one of the aft observation windows, "they'll foul us, and—"
His remarks were interrupted by a jar to the Advance. She seemed to shiver and careened to one side. Then came another bump.
"Slow down!" cried the captain, rushing toward the pilot house.