"Then somebody has been at your box, Tim, and they took out our regular fuses and put in these quicker ones. It's a game to make trouble for us among our men, and to damage the tunnel."
"Bless my rubber boots!" cried Mr. Damon. "Who would do a thing like that?"
"Our rivals, perhaps, though I do not like to accuse any man on such small evidence," said Walter. "But we must adopt new measures."
"And be very careful of the fuses," said Job.
"Thot's what I will!" declared Tim. "I'll put th' supply in a new place. No wonder there was blasts before th' min could git out th' way! Bad cess t' th' imps thot did this!" and he banged his big fist down on the table.
Since the trouble began a guard had been always posted around the tunnel entrance and surrounding buildings, and this night the patrol was doubled. Tom, Mr. Damon and the two Titus brothers sat up quite late, talking over plans and ideas.
Professor Bumper went to bed early, as he said he was going to set off before sunrise to make a search for the lost city.
"I regard him as more or less of a visionary," said Mr. Job Titus; "but he seems a harmless gentleman, and we'll do all we can to help him."
"Surely," agreed his brother.
The night was not marked by any disturbance, and after breakfast, Tom, under the guidance of the Titus brothers, looked over the tunnel with a view to making his first experiment with the new explosive.