The Time Traveller (the man who will travel through time) talked to his friends. He explained a difficult idea to us. His eyes were bright and his face was red with excitement. The fire in the room was warm and bright. The soft light from the lamps shone on our glasses.
We sat in very comfortable chairs. The Time Traveller invited these chairs himself. We felt very relaxed after dinner. We listened to his new ideas. The Time Traveller used his finger to point as he spoke.
"You must listen to me carefully," the Time Traveller said. "I must change some of your ideas. For example, the geometry (the study of lines and shapes) you learned at school is wrong."
Filby was a man with red hair who liked to argue. Filby said, "That is a very big thing to say!"
"I will give you a good reason to believe me," the Time Traveller said. "You know that a mathematical line is not real. It has no thickness. A plane (a flat surface like a piece of paper) is also not real. These things are only ideas."
The Psychologist said, "That is true."
"A cube (a solid object with six square sides) must have length, width, and thickness," the Time Traveller said. "But a cube cannot be real if it does not last for any time."
Filby did not understand. "I do not follow you," Filby said.
The Time Traveller asked, "Can a cube exist if it lasts for zero seconds?"
Filby thought about this. The Time Traveller continued. "Any real body must have four directions. It must have Length, Width, Thickness, and Duration (how long something lasts). But people often forget this fact."
The Time Traveller explained that there are four dimensions (ways to measure something in space and time). Three dimensions are in Space. The fourth dimension is Time.
The Time Traveller said, "Our minds move in one direction along Time. We move from the start of our lives to the end. But Time is just like Space."
A Very Young Man tried to light his cigar (a roll of dried tobacco for smoking). He said the idea was very clear.
The Time Traveller was happy. He said, "This is what we mean by the Fourth Dimension. It is only another way of looking at Time. There is no difference between Time and Space. But our minds move along Time."
The Provincial Mayor said, "I have not heard this before."
The Time Traveller explained more. He said that Space has three dimensions. These are Length, Width, and Thickness. Some scientists want to find a fourth direction. They want to make a new kind of geometry.
The Provincial Mayor moved his lips. He tried to understand the idea. After a short time, the Provincial Mayor said, "Yes, I think I see it now."
The Time Traveller told us he was working on this new geometry. He showed us a portrait of a man at different ages. The man was eight years old, then fifteen, then twenty-three. The Time Traveller said these were different parts of the man's life in Time.
The Time Traveller paused so we could think. Then he said, "Scientific people know that Time is a kind of Space. Look at this diagram (a drawing that explains information)."
The Time Traveller showed us a weather record. He moved his finger along a line. The line showed the movement of a barometer (a tool that measures the air to predict the weather).
The line moved up and down. This showed the movement of the mercury (a silver liquid inside the tool) through Time. The Time Traveller said this line was in the Time-Dimension.
The Medical Man looked at the fire. He asked, "If Time is a dimension, why is it different? Why can we not move in Time like we move in Space?"
The Time Traveller smiled. He asked if we can really move freely in Space. He said we can move left, right, forward, and backward. But gravitation (the force that pulls things to the ground) stops us. It is hard to move up and down.
The Medical Man said, "We have balloons (large bags of gas that fly in the sky)."
The Time Traveller said that before balloons, men could not move up. They could only jump a little bit. It was much easier to go down than up.
"And you cannot move in Time at all," the Medical Man said. "You must stay in the present moment."
"That is where you are wrong," the Time Traveller said. "We are always moving away from the present moment. Our lives move through Time at a steady speed. We move from the cradle (a baby's small bed) to the grave."
The Psychologist interrupted. He said, "But you can move in all directions in Space. You cannot move in all directions in Time."
The Time Traveller said, "That is my great discovery! You are wrong. When I remember the past, I go back to that moment. I stay there for a second. We cannot stay in the past for a long time, but a man in a balloon can go up. Why can a man not move through Time?"
Filby said, "This is against reason."
"Why?" asked the Time Traveller.
Filby said, "You can use words to show that black is white. But you will never convince me."
The Time Traveller said, "Maybe not. But I have a plan for a machine."
"To travel through Time!" the Very Young Man cried.
The Time Traveller said the machine would travel in any direction in Space and Time. The driver would choose the direction. Filby laughed at this idea.
"I have an experiment," the Time Traveller said.
The Psychologist said a Time Machine would be very useful. A person could travel back to see the Battle of Hastings. The Medical Man said that people in the past might be angry if they saw a stranger from the future.
The Very Young Man wanted to learn Greek from the famous writers Homer and Plato. He also wanted to visit the future. He wanted to leave his money in a bank and see it grow.
I said, "You might find a new kind of society in the future."
The Psychologist said these ideas were wild. The Time Traveller said he was going to prove his ideas with an experiment. Filby was tired, but he wanted to see it.
The Time Traveller smiled at us. He put his hands in his pockets and walked out of the room. We heard his slippers (soft shoes for the house) on the floor. He went to his laboratory (a room for scientific work).
The Psychologist wondered what the Time Traveller was doing. The Medical Man thought it was a trick. Filby began to tell a story about a conjuror (a person who performs magic tricks). But the Time Traveller came back, and Filby stopped his story.