Mr. Damon, of the three who heard Professor Bumper make this statement, showed the least sign of astonishment. It would have been more correct to say that he showed none at all. But Tom could not restrain himself.

"The lost city of Pelone!" he exclaimed.

"Is it here--in these mountains?" asked Mr. Titus.

"I have reason to hope that it is," went on the professor. "The golden tablets are very vague, but I have tried many locations, and now I am about to try here. I hope I shall succeed. At any rate, I shall have agreeable company, which has not always been my luck on my previous expeditions seeking to find the lost city."

"Oh, Professor, are you still on that quest?" asked Mr. Damon, in a matter-of-fact tone.

"Yes, Mr. Damon, I am. And now that I look about me, and see the shape of these mountains, I feel that they conform more to the description on the golden plates than any location I have yet tried. Somehow I feel that I shall be successful here."

"Did you know Professor Bumper was searching for a lost city of the Andes?" asked Tom, of his eccentric friend.

"Why yes," answered Mr. Damon. "He has been searching for years to locate it."

"Why didn't you tell us?" inquired Mr. Titus.

"Why, I never thought of it. Bless my memorandum book! it never occurred to me. I did not think you would be interested. Tell them your story, Professor Bumper."

"I will soon. Just now I must see to my equipment. The story will keep."

And though Tom and Mr. Titus were both anxious to hear about the lost city, they, too, had much to do to get ready for the trip into the interior.

The beginning of the tunnel under one of the smaller of the ranges of the Andes lay two days journey from the end of the railroad line. And the trip must be made on mules, with llamas as beasts of burden, transporting the powder and other supplies.

"We'll only need to take enough food with us for the two days," said Mr. Titus. "We have a regular camp at the tunnel mouth, and my brother has supplies of grub and other things constantly coming in. We also have shacks to live in; but on this trip we will use tents, as the weather at this season is fine."

It was quite a little expedition that set off up the mountain trail that afternoon, for they had arrived at the end of the railroad line shortly before dinner, and had eaten at a rather poor restaurant.

Professor Bumper had made up his own exploring party, consisting of himself and three native Indian diggers with their picks and shovels. They were to do whatever excavating he decided was necessary to locate the hidden city.

Several mules and llamas, laden with the new explosive, and burdened with camp equipment and food, and a few Indian servants made up the cavalcade of Tom, the contractor, Mr. Damon and Koku. The giant was almost as much a source of wonder to the Peruvians as he had been on board the ship. And he was a great help, too. For some of the Indians were under-sized, and could not lift the heavy boxes and packages to the backs of the beasts of burden.

But Koku, thrusting the little men aside, grasped with one hand what two of them had tried in vain to lift, and set it on the back of mule or llama.

The way was rough but they took their time to it, for the trail was an ascending one. Above and beyond them towered the great Andes, and Tom, gazing up into the sky, which in places seemed almost pierced by the snow-covered peaks, saw some small black specks moving about.

"Condors," said Mr. Titus, when his attention was called to them. "Some of them are powerful birds, and they sometimes pick up a sheep and make off with it, though usually their food consists of carrion."

They went into camp before the sun went down, for it grew dark soon after sunset, and they wanted to be prepared. Supper was made ready by the Indian helpers, and when this was over, and they sat about a camp fire, Tom said:

"Now, Professor Bumper, perhaps you'll explain about the lost city."

"I wish I could explain about it," began the scientist. "For years I have dreamed of finding it, but always I have been disappointed. Now, perhaps, my luck may change."

"Do you think it may be near here?" asked Mr. Titus, motioning toward the dark and frowning peaks all about them.

"It may be. The signs are most encouraging. In brief, the story of the lost city of Pelone is this. Thousands of years ago--in fact I do not know how many--there existed somewhere in Peru an ancient city that was the centre of civilization for this region. Older it was than the civilization of the Mexicans--the Montezumas--older and more cultured.

"It is many years since I became interested in Peruvian antiquities, and then I had no idea of the lost city. But some of the antiques I picked up contained in their inscriptions references to Pelone. At first I conceived this to be a sort of god, a deity, or perhaps a powerful ruler. But as I went on in my work of gathering ancient things from Peru, I saw that the name Pelone referred to a city--a seat of government, whence everything had its origin.

"Then I got on the track more closely. I examined ancient documents. I found traces of an ancient language and writings, different from anything else in the world. I managed to construct an alphabet and to read some of the documents. From them I learned that Pelone was a city situated in some fertile valley of the Andes. It had existed for thousands of years; it was the seat of learning and culture. Much light would be thrown on the lives of the people who lived in Peru before the present races inhabited it, if I could but locate Pelone.

"Then I came across two golden tablets on which were graven the information that Pelone had utterly vanished."

"How?" asked Tom.

"The golden tablets did not say. They simply stated the fact that Pelone was lost, and one sentence read: 'He who shall find it again shall be richly rewarded.' But it is not for that that I seek. It is that I may give to the world the treasures it must contain--the treasures of an ancient civilization."

"And how do you think the city disappeared?" asked Mr. Titus.

"I do not know. Whether it was destroyed by enemies, whether it was buried under the ashes of a volcano, whether it still exists, deserted and solitary in some valley amid the mountain fastnesses of the Andes, I do not know. But I am certain the city once existed, and it may exist yet, though it may be in dust-covered ruins. That is what I seek to find. See! Here are the tablets telling about it. I got them from an old Peruvian grave."

He took from a box two thin sheets of yellow metal. They were covered with curious marks, but Tom and the others could make nothing of them. Only Professor Bumper was able to decipher them.

"And that is the story of the lost city of Pelone --as much as I know," he said. "For years I have sought it. If I can find it I shall be famous, for I shall have added to human knowledge."

"If the people of that city wrote on golden tablets, the yellow metal must have been plentiful," commented Mr. Titus. "You might strike a rich mine."

"I have no use for riches," said the professor.

"Well, I have," the contractor said, with a laugh. "That's why I'm putting through this tunnel. And if my brother and I don't do it we'll be in a bad way financially. We have struck traces of gold, but not in paying quantities. I should like to see this lost city of yours, Professor Bumper. It may contain gold."

"You may have all the gold, if I am allowed to keep the antiquities we find," stipulated the scientist. "Then you will help me in my search?"

"As much as we can spare time for from the tunnel work," promised Mr. Titus. "I'll instruct my men to keep their eyes open for any sign of ancient writings on the rocks we blast out."

"Thank you," said the professor.

The night passed uneventfully enough, if one excepts the mosquitoes which seemed to get through the nets, making life miserable for all. And once Tom thought he heard gruntings in the bush back of the tent, which noises might, he imagined, have been caused by a bear. Toward morning he heard an unearthly screech in the woods, and one of the Indians, tending the fire, grunted out a word which meant pumas.

"I can see it isn't going to be dull here," Tom mused, as he turned over and tried to sleep.

Breakfast made them all feel better, and they set off on the final stage of their journey.

"If all goes well we'll be at the tunnel entrance and camp to-night," said the contractor. "This second half of the trip is the roughest."

There was no need of saying that, for it was perfectly evident. The trail was a most precarious one, and only a mule or llama could have traveled it. The mules were most sure-footed, but, as it was, one slipped, and came near falling over a cliff.

But no real accident occurred, and finally, about an hour before sunset, the cavalcade turned down the slope and emerged on a level plain, which ended against the face of a great cliff.

As Tom rode nearer the cliff he could make out around it groups of rude buildings, covered with corrugated iron. There was quite a settlement it seemed.

Then, in the face of the cliff there showed something black--like a blot of ink, though more regular in outline.

"The mouth of the tunnel," said Mr. Titus to Tom. "Come on over to the office and I'll introduce you to my brother. I guess he will be glad we've arrived."

Tom dismounted from his mule, an example followed by the others. Professor Bumper gazed up at the great mountains and murmured:

"I wonder if the lost city of Pelone lies among them?"

Suddenly the silence of the evening was broken by a dull, rumbling sound.

"Bless my court plaster!" cried Mr. Damon. "What's that?"

"A blast," answered Mr. Titus. "But I never knew them to set off one so late before. I hope nothing is wrong!"

And, as he spoke, panic-stricken men began running out of the mouth of the tunnel, while those outside hastened toward them, shouting and calling.