“Of course, if one road does that, it will not be any time before all the others will, too. It’ll not be long before we can be sitting in a car traveling, let us say from New York to Albany, and chat with a friend who may be on another train traveling between Chicago and Denver. Or if a business man has started from New York to Chicago and happens to remember something important in his office he can call up his manager and give him directions just the same as though he pressed a buzzer and called him in from the next room.”
“It sounds like magic,” remarked Bob, drawing a long breath.
“If we’d even talked about such things a few hundred years ago we’d have been burned at the stake as wizards,” laughed the doctor.
“The most important thing about this railroad development,” he went on, “is not the convenience it may be in social and business life, but in the prevention of accidents. As it is now, after a train leaves a station it can’t get any orders or information until it gets to the next station. A train may be coming toward it head on, or another train ahead of it and going in the same direction may be stalled. Often in the first case orders have come to the station agent to hold a train until another one has passed. But the station agent gets the message just a minute too late, and the train has already left the station and is rushing on to its fate. Then all the agent can do is to shudder and wait for news of the crash. With the radio equipment he can call up the train, tell of the danger, and direct it to come back.
“Or take the second case where a train is stopped by some accident and knows that another train is coming behind it on the same track and is due in a few minutes. All they can do now is to send back a man with a red flag to stop the second train. But it may be foggy or dark, and the engineer of the second train doesn’t see the flags and comes plunging on into the first train. With the radio, the instant a train is halted for any reason, it can send a message to the second train telling just where it is and warning of the danger. Hundreds have been killed and millions of dollars in property have been lost in the past just because of the old conditions. With the radio installed on trains, that sort of thing will be made almost impossible in the future.
“But there,” he said, with a smile, “I came up here to answer your questions, and I’ve been doing all the talking. Now just what is it you wanted to ask me about radio?”
[CHAPTER VI—THE WONDERFUL TUBE]
“It’s about getting a vacuum tube,” replied Bob, in answer to the doctor’s question. “The crystal detector is all right when we use the ear pieces. But we got to thinking about a horn so that lots of people could enjoy the concerts at the same time, and we figured that the crystal wouldn’t be quite good enough for that.”
The doctor smiled genially.
“I knew you’d be wanting that sooner or later,” he said. “It’s the second natural step in radio development. While you were still getting familiar with the working of the wireless, the crystal would do very well. But there comes a time to all amateurs when they get to hankering after something that is undeniably better. And the vacuum tube is that thing.”