"Do you really mean that?" asked the young inventor, looking around to make sure his father was not present. On account of Professor Swift's weak heart, Tom wished to spare him all possible worry.
"I certainly do mean it," insisted Lieutenant Marbury. "And, while I am rather amazed at the news of the fire, for I did not think the plotters would be so bold as that, it is in line with what I expected, and what we suspected in Washington."
"And that was—what?" asked Tom.
"The existence of a well-laid plot, not only against our government, but against you!"
"And why have they singled me out?" Tom demanded.
"I might as well tell it from the beginning," the officer went on. "As long as you have not received any official warning from Washington you had better hear the whole story. But are you sure you had no word?"
"Well, now, I won't be so sure," Tom confessed. "I have been working very hard, the last two days, making some intricate calculations. I have rather neglected my mail, to tell you the truth.
"And, come to think of it, there were several letters received with the Washington postmark. But, I supposed they had to do with some of my patents, and I only casually glanced over them. There was one letter, though, that I couldn't make head or tail of."
"Ha! That was it!" cried the lieutenant. "It was the warning in cipher or code. I didn't think they would neglect to send it to you."
"But what good would it do me if I couldn't read it?" asked Tom.