That night the adventurers slept more soundly than they had since entering the strange world. They felt they had nothing to fear from the giants. In the morning they were not molested, though big crowds gathered to look at the ship. But they kept back a good distance. The machinery was found to be in good shape, save for a few repairs, and when these were made, the professor announced he would start on a long journey. For several weeks after that the travelers swung about in their ship, sometimes sailing in the air and again on big seas and lakes viewing the wonders of the inner world. They were many and varied, and the professor collected enough material for a score of books which he said he would write when he got back to the outer world once more. One afternoon, as they were sailing over a vast stretch of woodland, which did not seem to be inhabited, Mr. Henderson, looking at one of the gages on the wall, asked: “Boys do you know how far you have traveled underground?” “How far?” asked Jack, who hated to guess riddles. “More than four thousand miles,” was the answer. “But we haven’t come to that mountain of gold and diamonds,” said Mark. “I am anxious to see that.” “Have patience,” replied the professor. “I have not steered toward it yet. There are other things to see.” Just then Washington’s voice could be heard calling from the conning tower: “We’re coming to a big mountain!” CHAPTER XXVIII THE TEMPLE OF TREASURE “What’s that?” fairly yelled the professor. “We am propelling ourselves in a contiguous direction an’ in close proximity to an elevated portion of th’ earth’s surface which rises in antiguous proximity t’ th’ forward part of our present means of locomotion!” said the colored man in a loud voice. “Which means there may be a collision,” the professor said, as he and the boys hurried toward the tower. “Jest what I said,” retorted Washington. “What’ll I do?” “Send the ship a little higher,” answered Mr. Henderson. “We mustn’t hit any mountains.” Washington forced more gas into the holder, and speeded the negative gravity machine up some, so that the _Mermaid_, which was flying rather low, ascended until it was in no danger of colliding with the peak which reared its lofty height just ahead of them. As the ship sailed slowly over the mountain, Mark gazed down and exclaimed: “Doesn’t that look like the ruins of some building?” The professor took a pair of field glasses from a rack in the wall and took a long view. “It must be the place,” he said in a low voice. “What place?” asked Jack. “The temple of treasure,” was the answer. “Hankos told me it was on top of the highest mountain in the land, and this must be it, for it is the loftiest place we have seen. But we must be careful, for there is danger down there.” “What kind?” asked Mark.