utation,
but looked at the two in a puzzled sort of fashion.

"I beg your pardon," he remarked, "but your faces are familiar, though
I cannot recall your names. Haven't I seen you before?"

"You have," said Tom, with a smile. "You saved our lives from a bomb
the other day."

"Oh, yes! So I did! So I did!" exclaimed Professor Bumper. "I felt
sure I had seen you before. Are you all right?"

"Yes. There haven't been any more bombs thrown at us," the contractor
said. "By the way, Professor Bumper, I understand you are quite a
traveler in the Andes, in the vicinity of Lima."

"Yes, I have been there," admitted the bald-headed scientist in guarded
tones.

"Well, I am digging a tunnel in that vicinity," went on Mr. Titus, "and
if you ever get near Rimac, where the first cutting is made, I wish you
would come and see me--Tom too, as he is associated with me."

"Rimac-Rimac," murmured the professor, looking sharply at the
contractor. "Digging a tunnel there? Why are you doing that?" and he
seemed to resent the idea.

"Why, the Peruvian government engaged me to do it to connect the two
railroad lines," was the answer. "Do you know anything about the place?"

"Not so much as I hope to later on," was the unexpected answer. "As it
happens I am going to Rimac, and I may visit your tunnel."

"I wish you would," returned Mr. Titus.

Later on, in their stateroom, the contractor remarked to the young
inventor:

"Sort of queer; isn't it?"

"What?" asked Tom. "His not remembering us?"

"No, though that was odd. But I suppose he is forgetful, or pretends to
be. I mean it's queer he is going to Rimac."

"What do you mean?" asked Tom.

"Well, I don't know exactly what I mean," went on the tunnel
contractor, "but our tunnel happens to start at Rimac, which is a small
town at the base of the mountains."

"Maybe the professor is a geologist," suggested Tom, "and he may want
to get some samples of that hard rock."

"Maybe," admitted Mr. Titus. "But I shall keep my eyes on him all the
same. I'm not going to have any strangers, who happen to be around when
bombs drop near us, get into my tunnel."

"I think you're wrong to doubt Professor Bumper," Tom said.

A few days after this, when Tom and Mr. Titus were casually discussing
the weather on deck and wondering how much longer it would be before
they reached Callao, Mr. Damon, who had been playing numberless games
of chess, came up for a breath of air.

"Mr. Damon," call