"They are seeking to strike at the United States through you," was the answer. "They don't want Uncle Sam to have such formidable weapons as your great searchlight, the giant cannon, or this new warship of the clouds."
"But why not, as long as the United States does not intend to go to war with any of the foreign nations?" Tom inquired.
"No, it is true we do not intend to go to war with any of the conflicting European nations," admitted Lieutenant Marbury, "but you have no idea how jealous each of those foreign nations is of all the others. Each one fears that the United States will cease to be neutral, and will aid one or the other."
"Oh, so that's it?" exclaimed Tom.
"Yes, each nation, which may, at a moments notice, be drawn into a war with one or more rival nations, fears that we may throw in our lot with its enemies."
"And, to prevent that, they want to destroy some of my inventions?" asked Tom.
"That's the way I believe it will work out. So you must be careful, especially since you have taken on so many new men."
"That's so," agreed the young inventor. "I have had to engage more strangers than ever before, for I am anxious to get the Mars finished and give it a good test. And, now that you have mentioned it, there are some of those men of whom I am a bit suspicious."
"Have they done anything to make you feel that way?" asked the lieutenant.
"Well, not exactly; it is more their bearing, and the manner in which they go about the works. I must keep my eye on them, for it takes only a few discontented men to spoil a whole shop full. I will be on my guard."