Tom had a theory, which he did not disclose to Mr. Titus, that, after all, the somewhat mysterious Senor Pinto might, in some way, be mixed up in the bomb attempt. But a close questioning of the steward on duty near the foreigner's cabin at the time disclosed the fact that Pinto had been ill in his berth all that day.
"Well, unless the bomb fell from some passing airship, I don't see how it got on deck," said Tom with a shake of his head. "And I'm sure no airship passed over us."
They had kept the matter secret, not telling even Mr. Damon, for they feared the eccentric man would make a fuss and alarm the whole vessel. So Mr. Damon, occasionally blessing his necktie or his shoe laces, played chess with his elderly gentleman friend and was perfectly happy.
That Professor Bumper not only had kept his promise about not mentioning the bomb, but that he had forgotten all about it, was evident a day or two after the happening. Tom and Mr. Titus passed him on deck, and bowed cordially. The professor returned the salutation, 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."