But what particularly struck the fancy of the boys was a strange ram-like nose that projected straight out from the bow of this odd-looking craft. At this distance it looked like a series of huge steel cistern sections linked together after the fashion of a long sewer system. For approximately a hundred feet this cylindrical projection extended out from the bow of the _Jules Verne_. Less than a third of it was exposed to view, the remainder being under water. At the end it terminated in a queer flatiron-shaped turret something like eight or ten feet across at the back and tapering forward to a thin prow of inches. Truly this was a strange looking outfit! Never in all their maritime experience had the boys seen anything like it. "You sure have one on me," faltered Dick as he surveyed the craft. Jay was shaking his head too. "Might be the houseboat on the Styx so far as my store of knowledge is concerned." Captain Austin turned to Larry Seymour. "What do you think of her?" "Nix for me, Captain; you have me buffaloed," was all Larry could hazard. Captain Austin laughed aloud. "I thought you chaps would be surprised. Well, now let's see. The _Jules Verne_ is the mother ship"--he pointed out the "houseboat" that had first caught the eyes of the boys. "She is nothing more than an old Fall River liner that we bought in and converted into our own uses. She is simply the base of operations. We live on the _Jules Verne_. She takes us wherever we want to go and she is entirely seaworthy, I assure you. "Now, look at the access tube." The captain was pointing now to the long cylindrical tube that led away forward from the bow of the _Jules Verne_. "That is the way we get into the _Nautilus_. Oh, yes, the _Nautilus_ is really the big secret of our plan. It is the small diving compartment that sets out there in the water." "You mean the flatiron-shaped section nearly awash?" queried Dick. "Exactly," replied the captain. "Call it a diving bell if you will. What we have here is two distinct vessels connected by a long passageway. 'The Subway' as Superintendent Brown calls it. First we go aboard the _Jules Verne_. Then we find the lost ship on the bottom of the sea that we want to work on. When we are ready we lower the access tube and the _Nautilus_ right over the wreck. Down goes the tube. Down we climb just like walking down an enclosed ladder. Through the air-lock--and there we are in the _Nautilus_! Don't you get it?" Jay and Dick nodded understandingly. "Tell us more about the _Nautilus_," asked Dick inquisitively.