Three days after reaching the capital, Mr. Titus having attended to some necessary business while Mr. Damon set on foot matters connected with his affairs, it was decided to strike inland to Rimac, and to try the effect of Tom Swift's explosive on the tunnel.
The journey was to be made in part by rail, though the last stages of it were over a rough mountain trail, with llamas for beasts of burden, while our friends rode mules.
As Tom, Mr. Damon, Koku, and Mr. Titus were going to the railroad station they saw Professor Bumper also leaving the hotel.
"I believe our roads lie together for a time," said the bald-headed scientist, "and, if you have no objections, I will accompany you."
"Come, and welcome!" exclaimed Mr. Titus, all his suspicions now gone.
"And it may be that you will be able to help me," the scientist went on.
"Help you—how?" asked Tom.
"I will tell you when we reach the Andes," was the mysterious answer.
It was a day later when they left the train at a small station, and struck off into the foothills of the great Andes Mountains, where the tunnel was started, that the professor again mentioned his object.
"Friends," he said, as he gazed up at the towering cliffs and crags, "I am searching for the lost city of Pelone, located somewhere in these mountains. Will you help me to find it?"