"We'll take it with us. We can put a few of the forks and spoons in our pockets and the bowl can be slung from a staff and carried by two of us. Mind how you carry it, Green." As soon as the three Scouts returned to their waiting companions, the silver was distributed for the sake of easier carriage, and the march of exploration resumed. Presently, instead of continuing the upward slope, the tunnel dived with considerable abruptness. At the bottom of the dip there was water on the floor to the depth of six inches, while from the signs of excessive moisture on the walls and ceiling it was fairly conclusive that the whole of this portion of the tunnel had recently been flooded. A slight stream of water was still running from a fissure in the wall. "This must be a proper trap in wet weather," said Phillips. "The water lodges in the dip until it soaks out again. That accounts for the fact that Tassh was unable to return to Polkerwyck House on the night of the storm." "It certainly seems like it," said Green, as he splashed boldly through the water. "Doesn't it feel cold?" From this point the tunnel again sloped upwards, in places so steeply that the incline had to be broken by short flights of steps. "I reckon we've come quite two miles," said Baker, "and in a fairly straight direction according to my compass. If I had known----" The remark was suddenly cut short by a low warning whistle from Atherton. The rest of the patrol closed upon their Leader, who had come to a standstill before a blank wall. Right and left were short passages terminating in spiral flights of steps. Once more Atherton and his two chosen comrades began their subsidiary investigations, while the remaining members of the "Otters" remained at the junction of the two cross-ways. It was not long before the Leader returned. "No go," he announced. "There are only eleven stairs and then a bricked-up wall. By the undisturbed state of the dust on the steps we know that no one has been there for months at the very least. Come on, all of you, we'll try our luck with this branch." Round and round, up and up, went the Scouts. They realised that they were on the eve of an important discovery, for here there were undoubted traces of human footsteps. At the fifty-fourth step, Atherton found farther progress barred by a stone wall, each block being roughly fifteen inches wide and twelve high, and set in hard, black cement. The Scouts looked at each other with feelings akin to dismay. It seemed hard lines, after traversing the whole length of the subterranean passage, to find a blank wall. "I'll tell you what, Atherton," said Green. "It's my opinion that Tassh, or whoever it is, discovered the tunnel at the Seal Island end, and, like us, explored it as far as it went. He then had to retrace his footsteps, and that accounts for the complicated nature of the trail."