Mark, who was near the metal box, did so. But even the power of Cardite was of no avail against the awful suction of the whirlpool. The boat began to go around in a great circle, ever coming nearer and nearer to the black, swirling center. "No wonder they needed no guards on the water side," gloomily observed Mr. Roumann as he stood up and looked at the hills. "The whirlpool is the best protector they could have." In deadly peril, the adventurers watched their boat coming nearer and nearer to the terrible center of the angry waters. CHAPTER XXVII GETTING THE CARDITE "Isn't there any way of escape?" asked Jack in a low voice, as he crouched in the bow and peered into the whirlpool, on the edge of which they were circling. "I don't see any," replied Mr. Roumann. "I am very sorry I got you into this trouble. If I had not insisted on coming for the red substance we would not be in this danger." "It's as much our fault as yours," declared the professor. "We were anxious to get some of the treasure also." "And now none of us will have any use for it," observed Andy dryly. "When we slide down into that hole it will be all up with us." They all shuddered as they saw the black hole, around which the waters raced in a circle. "I wonder what's down there?" asked Mark. "It isn't a good thing to think about," responded Jack. "I always was afraid of whirlpools." The boat was now beginning to go around faster. The occupants were getting dizzy with the motion. They could hear a distant roar, and knew that it came from the water falling down some great depth, into which they seemed fated to be dashed. "Did you turn on all the power of the boat?" asked Jack after a period of silence. "Seems to me we didn't come along very fast in this craft. The one we were in first went at a great rate. Maybe we don't understand how to make it go at top speed." "I turned the knobs every way I could think of," replied Mr. Roumann. "But it would take terrific speed and power to free us from the suction of the whirlpool." Jack moved back to the stern, where the box was, containing the red substance that furnished power to move the boat. He looked closely at it. Meanwhile the boat was moving around in ever-narrowing circles, faster and faster. Jack noticed that twice in each revolution it went respectively lower and higher on the course, and always at the same places. That is to say, the whirlpool was on what might be termed a slant. At one time the boat would be at the lowest point, and at another at the highest point. At the low point the occupants of the craft were out of sight of everything, as when a ship is in the hollow of the sea. A little later they would be raised up on a crest of water so that they could look to the distant hills. "If we could only get power enough to shoot the boat out at an angle when it gets to the high point, we could escape," thought Jack.