"Now you get the advantage of this system, boys," the superintendent was saying. "Here you are much safer and much more comfortable than if you were out there on the bottom floundering around in diving armor. You can just stand here at ease, breathing normally, with plenty of fresh oxygen pouring down from above, and with no unfavorable symptoms of any kind." To impress this point, the superintendent switched on an air-cock to emphasize the point that the _Nautilus_ was completely in touch with the mother ship up at the other end of the hundred-foot access tube. "Look here, boys!" Captain Austin, standing by one of the huge ports that dotted the face of the _Nautilus_ on either side of the prow, beckoned them to look out. Through the misty green of the water their eyes could carry quite a distance with the aid of the bright sunlight above. Certainly it was light enough so that in the event of any lost ship being encountered it could be seen in plenty of time. Through the floor of the _Nautilus_ the green of the sea showed all around. The water raced along under the glass of the aquascope as the _Nautilus_ was pushed steadily ahead. Virtually the whole floor of the diving bell was framed in a trap that could be raised and lowered at will; and, from their own knowledge of submarine affairs, the Brighton boys knew that with the air pressure within the _Nautilus_ equal to that of the water itself at a depth of one hundred feet, this flooring could be rolled back, and still the water would not come into the _Nautilus_! "I know just what you are thinking about," laughed the superintendent, as he caught a glimpse of Jay and Dick surveying the transparent flooring of the _Nautilus_. "You are thinking what a wonderful thing it is that we can open the bottom of a craft submerged one hundred feet down, and yet no water pour in upon us. And it truly is a wonderful thing. Just like the Lord opened the Red Sea and enabled the children of Israel to get across and outwit their pursuers." Larry Seymour, to whom the experience was all new, was losing no part of the proceedings. "But what if your air pump went on the bum about the time you opened up that flooring?" he questioned. "If the air pump failed, it would not affect the water, but would cut off our breathing supply," answered the official. "How long could we last down here?" "Oh, two or three of us working alone could stand it for some hours without any relief." "Suppose some one opened the breech caps leading out into the access tube while the aquascope was up?" "Wow-wow! In would come Mr. Ocean, and I guess it would be all day for the chaps who would be caught down here."