lines can be approached as silently as the Indians used to approach the log cabins of the white settlers. That will be its great advantage—not that conversation can be more easily carried on, for that is, after all, an unimportant detail. But to approach the enemy's lines in the silence of the night would be a distinct gain."

"I believe it would, Tom!" exclaimed Mr. Damon. "And I should think, too, that Uncle Sam would be glad to get such a motor," he added.

"Well, he'll have one to take if he wants it, if I can make my plans a success," declared Tom. "That is, unless those other fellows get ahead of me."

"What other fellows?" asked Mr. Damon.

"Gale, Ware and their crowd," was the answer. "I fancy they are provoked because I wouldn't agree to work for them, and now, that Gale overheard—as he must have—what I propose working on, they may try that game themselves."

"You mean try to turn out a silent motor?"

"Yes. It would be a big feather in their cap for their company, so far, hasn't been very successful on government orders. That's why they came to me, I guess."

"I shouldn't be surprised, Tom," conceded Mr. Damon. "Since the government accepted your giant cannon and your great searchlight, you have come into greater prominence than ever before. And those two things are a wonderful success."

"Yes," admitted Tom, modestly enough, "the big electric light seems to have been of some benefit on the European battle front, and though they haven't been able to make and transport as many of my giant cannons as I'd like to see over there, it is progressing, I understand."

And this is true. For the details of these two inventions of Tom Swift's I refer my readers to the books bearing those titles. Sufficient to state here that the government was using these two inventions, and there had been no necessity for commandeering them either, since Tom had freely offered them at the declaration of war with Germany.

"Well, since I can't help you with my 'Whizzer,'" said Mr. Damon, with a smile, "let me do what I can toward your silent motor, Tom. What are you going to call it?"