The Time Traveller (which is the best name to call him) was explaining a very difficult idea to us. His grey eyes shone brightly, and his pale face was full of energy. The fire burned warmly in the room. We sat in comfortable chairs after a wonderful dinner. In this relaxing atmosphere, it was easy to just sit back and listen to him.
"You must follow me carefully," he said, pointing a thin finger at us. "I have to argue against some ideas that everyone believes. For example, the maths you learned at school is wrong. They taught you about shapes and lines, but they forgot something completely."
"That is a big thing to ask us to believe," said Filby, a man with red hair who loved to argue.
"I do not ask you to believe anything without a good reason," the Time Traveller went on. "But think about this: can a real box exist if it does not last for any time at all?"
Filby thought for a moment. "Well, no," he said.
"Exactly!" the Time Traveller said happily. "A real object must have four measurements: Length, Width, Height, and Time. We usually call Time the Fourth Dimension. We just do not notice it because we always move forward in Time, from the beginning to the end of our lives."
The Very Young Man tried to light his cigar. "Yes, that is very clear," he agreed.
"But," said the Medical Man, looking into the fire, "if Time is really a fourth dimension, why can't we move around in it? We can move left and right, backward and forward in space."
The Time Traveller smiled. "Are you sure we can move freely in space? We can move left and right, yes. But what about up and down? Gravity pulls us down."
"We have hot air balloons," the Medical Man answered.
"True, but it is much easier to go down than up," said the Time Traveller. "However, you think we cannot move in Time at all. You think we cannot get away from the present moment. That is where the whole world is wrong."
The Psychologist shook his head. "You can move about in space, but you cannot stop or go back in Time."
"That is my great discovery!" the Time Traveller said. "You are wrong. For example, when I remember a past event very clearly, I jump back to that moment in my mind. Of course, we cannot stay in the past for long. But a modern man can build a balloon to fly up against gravity. So, why shouldn't he build a machine to stop, or even travel backward, through Time?"
"You mean a machine to travel through Time?" asked the Very Young Man in surprise.
"Yes. A machine that can travel in any direction of Space and Time," the Time Traveller answered.
Filby laughed out loud. "It is against all reason! You will never make me believe it."
"Maybe not," said the Time Traveller. "But I have proof. I have done an experiment."
The other men started to joke about the idea.
"It would be very useful for historians," the Psychologist said. "You could travel back and find out the truth about famous battles!"
"Or you could go into the future," said the Very Young Man. "Just think! You could put your money in a bank, let it grow, and hurry on ahead to be rich!"
"Let us see your experiment anyway," said the Psychologist. "Although I am sure it is just a trick."
The Time Traveller smiled at us. With his hands deep in his pockets, he walked slowly out of the room. We heard him walk down the long hall to his laboratory.
"I wonder what he is going to show us?" the Psychologist asked.
"Probably just a magic trick," the Medical Man said. But suddenly, before anyone could say more, the Time Traveller came back.