The 100-foot mark was passed. Still the _S-18_ was going down. Roy Gould snapped on a switch. Powerful searchlights set in the outer hull especially for this operation cut the blackness of the water. Strange fish blinked their eyes and scuttled away from this monster which was invading the deep. Now Tim was at one of the quartz windows. In spite of their high power, the searchlights were effective for only a few feet. While he watched the gaunt mast of a ship came upward from the depths. They were descending almost on top of the Southern Queen. A stubby funnel, rising at a crazy angle, was next, and ahead of that Tim thought he could glimpse the battered bridge. The motion of the _S-18_ was almost imperceptible now. The divers, watching the descent closely, were giving orders which Earl Bell relayed on to the control room. The main deck of the Southern Queen, now heavily encrusted with sea growth, came into view and the _S-18_ slid lower. There was a gentle bump as it touched the bottom. Commander Ford came forward and took the telephone from Earl. There was a slight jar as the divers opened the outer door of their compartment and stepped outside the hull of the submarine. Pressure inside their own compartment and that outside had been equalized all of the way down and they were ready to seek an opening into the interior of the treasure ship. Moving slowly and with each carrying a hand torch, they disappeared beyond the outer rim of light. It was a tense group in the diving room, clustered around Commander Ford. Tersely he relayed the progress of the divers. "They're going back along the hull, hunting for an opening. Charlie Gill says the current is strong here but the footing is hard; probably volcanic rock." There was a moment of silence. Electric fans kept a constant flow of air. Commander Ford spoke again. "They're still moving back. Wait! Russ Graham's found a hole, probably the one knocked in the hull when the Southern Queen struck the reef. They're going inside!" Every word burned itself into Tim's memory. It took nerve even to go to the bottom of the ocean, but then to get out of a submarine in a diving suit and walk around the ocean floor and climb into the interior of an old hull took more than nerve. "They're not far from the ship's strong room," went on Commander Ford, each word low but distinct. Eagerly they waited for the next message from the interior of the Southern Queen. Would the divers be able to get into the strong room? Would the treasure be there? A dozen questions hammered through the mind of every man aboard the _S-18_. Roy Gould checked the even flow of air through the air lines. It was the life blood for the men outside. Once that stopped they wouldn't have a chance. Commander Ford bent nearer the mouthpiece of the phone, pressed the headset closer to his ears, straining for the first word of the treasure. His hands were shaking slightly. Then he turned toward them, his voice hoarse with excitement.