A DARING HOLDUP

Frank Brandon shook his head and smiled.

"I'm afraid I don't know much more to tell," he said. "As I have said, what will happen when we materially decrease the wave length, is still in the land of conjecture. But I tell you," he added, with sudden enthusiasm, "I'm mighty glad to be living in this good old age. What we have already seen accomplished is nothing to what we are going to see.

Why," he added, "some scientists, Steinmetz, for instance, are even beginning to claim that ether isn't the real medium for the propagation of radio waves."

"What do you mean by that?" asked Bob, with interest. "Is it some sort of joke?"

"Joke, nothing!" replied Frank Brandon. "As a matter of fact, I fully believe that electro-magnetic waves can as easily be hurled through a void as through ether."

The boys were silent for a moment, thinking this over. It sounded revolutionary, but they had great respect for Frank Brandon's judgment.

"There's the Rogers underground aerial," Bob suggested tentatively, and Brandon took him up quickly.

"Exactly!" he said. "That leans in the direction of what I say. Why, I believe the day is coming--and it isn't so very far in the future, either--when no aerial will be used.

"Why, I believe," he added, becoming more and more enthusiastic as he continued, "that ten years from now we shall simply attach our receiving outfits to the ground and shall be able to receive even more satisfactorily than we do to-day." He laughed and added lightly:

"But who am I to a.s.sume the role of prophet? Perhaps, like a good many prophets, I see too much in the future that never will come true."

"I don't believe it," said Bob. "I shouldn't wonder if all your prophesy will come true in a few years."

"Well," said Herb, with a grin, "it will be a relief not to get any more broken shins putting up aerials."

Mr. Brandon laughed.

"I'm with you," he said. "I've been there myself."

"Have you read about that radio-controlled tank?" Joe asked. "The one that was exhibited in Dayton, I mean?"

"I not only read about it, I saw it," Mr. Brandon answered, and the boys stared at him in surprise. "I happened to be there on business," he said; "and you can better believe I was on hand when they rolled that tank through the traffic."

"What did it look like?" asked Jimmy eagerly.

"The car was about eight feet long and three feet high," responded Brandon. "It was furnished with a motor and storage batteries, and I guess its speed was about five or six miles an hour."

"And was it really controlled by radio?" put in Herb, wishing that he had been on the spot.

"Absolutely," returned Brandon. "An automobile followed along behind it and controlled it entirely by wireless signals. The apparatus that does all the work is called the selector, and it's only about the size of a saucer. It decodes the dots and dashes and obeys the command in an inconceivably short time--about a quarter of a second."

"It can be controlled by an airplane, too, can't it?" asked Bob, and the radio inspector nodded.

"In case of war," he said slowly, "I imagine these airplane-controlled tanks could do considerable damage."

Their guest left soon after that, and, of course, the boys were sorry to have him go. His last words to them were about Ca.s.sey.

"Keep your eyes open for that scoundrel," he said, "and we'll find out what he's up to yet."

But in the next few days so many alarming things happened that the boys had little time to think about Dan Ca.s.sey. The alarming happenings consisted of a series of automobile robberies in neighboring towns, robberies committed so skillfully that no hint nor clue was given of the ident.i.ty of the robbers.

And then the robberies came nearer home, even into Clintonia itself. The president of one of the banks left his machine outside the bank for half an hour, and when he came out again it was gone. No one could remember seeing any suspicious characters around.

Then Raymond Johnston, a prominent business man of the town, had his car taken in the same mysterious manner from in front of his home. As before, no one could give the slightest clue as to the ident.i.ty of the thieves.

The entire community was aroused and the police were active, and yet the mystery remained as dark as ever.

Then, one day, Herb came dashing over to Bob's home in a state of wild excitement. Joe and Jimmy were already there, and Herb stopped not even for a greeting before he sprang his news.

"Say, fellows!" he cried, sprawling in a chair and panting after his run, "it's time somebody caught those auto thieves. They are getting a little too personal."

"What's up?" they demanded.

"One of dad's trucks has been held up!" gasped Herb. "In broad daylight, too!"

"Was anything taken?" asked Joe.

"Anything? Well, I should say! They looted the truck of everything. It's a wonder they didn't steal the machinery."

"That's a pretty big loss for your dad, isn't it?" said Bob gravely.

"It is!" replied Herb, running his fingers through his hair. "He's all cut up about it and vows he'll catch the ruffians. Though he'll have to be a pretty clever man if he does, I'll say."

"They do seem to be pretty slick," agreed Bob.

"I wonder if the same gang is responsible for all the robberies," put in Joe.

"It looks that way," said Jimmy. "It looks as if there were a crook at the head of the bunch who has pretty good brains."

"A regular master criminal, Doughnuts?" gibed Herb, then sobered again as he thought of his father's loss.

"It's bad enough," he said gloomily, "to hear of other people's property being stolen, but when it comes right down to your own family, it's getting a little too close for comfort."

"What is your dad going to do about it?" asked Bob.

Herb shrugged his shoulders in a helpless gesture.

"What can he do?" he asked. "Except what everybody else has done--inform the police and hope the rascals will be caught. And even if they are caught," he added, still more gloomily, "it won't do dad much good, except that he'll get revenge. The crooks will probably have disposed of all their stolen property before they're caught."

"Well, I don't know," said Bob hopefully. "Those fellows are getting a little bit too daring for their own good. Some day they'll go too far and get caught."

"I hope so. But crooks like that are pretty foxy," returned Herb, refusing to be cheered. "They're apt to get away with murder before they're caught."

The lads were silent for a moment, trying to think things out, and when Bob spoke he unconsciously put into words something of what his comrades were thinking.

"It seems as if radio ought to be able to help out in a case like this,"

he said, with a puzzled frown. "But I must say I don't see how it can."