It was not until after Mr.Gale had taken his leave and Tom had finished the particular work on which he was engaged when the president of the rival company came in, that the young man did some hard thinking.And this thinking was done after he had received a telephone call from Mary Nestor, asking, if by any chance, he had beard anything like a clew as to the whereabouts of her father.
Tom had been obliged to tell her that he had not.Everything possible was being done to find the missing man but he had disappeared as completely as though he had ridden on his bicycle into the crater of some extinct volcano on the meadow, and had fallen to the bottom.
An effort was made to trace him through an automobile association which had a large membership.That is, the members were asked to make inquiries to ascertain, if possible, whether any one had heard of an unreported accident--one in which Mr.Nestor might have been carried away by persons who accidently ran him down.
But this came to naught, and the police and other authorities were at a loss how farther to proceed.It was a theory in some quarters that Mr.Nestor was perfectly safe, but that he was out of his mind, and was either wandering around, not knowing who he was, or was, in this condition, detained somewhere, the persons having him in charge not realizing that he was the missing man so widely sought.
This belief was a relief to Mrs.Nestor and Mary in many ways for it prevented them from giving way to the fear that Mr.Nestor was dead.That he was alive was Tom Swift's firm opinion, and he was doing all he could to prove it.
It was not until the day after the visit of Mr.Gale that Tom, having concluded some intricate calculations about the strength of cylinder valves, uttered an exclamation.
"I wonder if he could have meant that?" cried the young inventor."I wonder if he could have meant that? I must find out at once! Queer I didn't think of that before!"He put in a long distance call to New York, asking to speak to Mr.Gale.But when, eventually, he was connected with the office of the Universal Flying Machine Company he was told that Mr.Gale and Mr.Ware had sailed for France that day, going over as government representatives to investigate aeroplane motors.Gale's visit to Tom had been just previous to taking the boat, it was said.
"This is tough luck!" mused Tom, his suspicions doubly aroused now."I can't let this rest here! I've got to get after it! As soon as I make this final test, and invite Uncle Sam's experts out to see how my noiseless motor works, I'll get after Gale and Ware if I have to follow them to the battlefields of France! I wonder if it was that he was hinting at all the while! I begin to believe it was!"Tom Swift had decided on another flight for his new craft before he would let the government experts see it.
"Silent Sam must do his very best work for Uncle Sam before I turn him over," said the young inventor.
"And after this flight I'll offer the machine to the government, and then devote all my time to finding Mr.Nestor," said Tom."I'd do it now, but private matters, however deeply they affect us, must be put aside to help win the war.But this will end my inventive work until after Mr.Nestor is found--if he's alive."Preparations for the test flight went on apace, and one afternoon Tom and Jackson took their places in the big, new aeroplane.He no longer feared daylight crowds in case of an accident.They made a good start, and the motor was so quiet that as Tom passed over his own plant the men working in the yard, who did not know of the flight, did not look up to see what was going on.They could not hear the engine.
"I think we've got everything just as we want it, Jackson," said Tom, much pleased.
"I believe you," answered the mechanician."It couldn't be better.Now if--"And at that moment there came a loud explosion, and Silent Sam began drifting rapidly toward the earth, as falls a bird with a broken wing.
