"Now to let some more air into the chamber." Immediately an air-cock was opened and with a hissing sound a great volume of compressed air came into the little chamber so tightly filled with humanity. Wsh-h-h-h-h! it resounded through the narrow space like the blow-off of a mighty steam exhaust. Just for a few seconds, and then it was turned off. Even though he had experienced divers aboard who were accustomed to working in high pressures below water, Superintendent Brown was taking no chances. It was always best to go slow, because with every foot of submergence there is an increase of air pressure upon every square inch of the body's surface of no less than .43 of a pound. At a depth of 100 feet under the sea the total pressure would be approximately 45 additional pounds pressure against every square inch of the body. With the average human body representing a surface of about 2160 square inches, that meant that at a depth of 100 feet a dead weight of more than 97,000 pounds would be pressing against the body of each of them. Under such circumstances the blood is forced away from the surface of the body. The veins become thin, while the deep-lying arteries are overworked. It was a matter of but a short time until, consulting the pressure gauge, the superintendent found that he had admitted a sufficient amount of compressed air to equalize the difference between the surface and the one-hundred-foot submarine level. "Now into the _Nautilus_!" As he said this, "Montey" opened the huge port leading into the diving chamber and stepped through. He was closely followed by the remainder of the party in single file, and presently they had emerged in the compartment or working chamber. Two or three men could work in it comfortably; five filled it too completely. There was just room for the quintet to stand about easily without bumping each other. Electric lights made the chamber as light as a Broadway office building in the evening. An electric fan buzzed in one corner to keep the air on the move. A telephone hung on the wall just to the left of Superintendent Brown's head. Just at that moment it tinkled merrily. The official took down the receiver. "Hello, hello. Yes, this is Brown. Yes, we are all fine and dandy. Yep. We are ready. Go ahead now." The superintendent turned from the telephone. "They are going to move us ahead slowly in the water now. All hands stand by. Maybe we may run into something." Just then a slight jarring motion indicated that the mother ship, the _Jules Verne_, had gotten under way, and was steering the tiny _Nautilus_ ahead of her through the waters of the Sound.