“You can show black is white by argument,” said Filby, “but you will never convince me.”

“Possibly not,” said the Time Traveller. “But now you begin to see the object of my investigations into the geometry of Four Dimensions. Long ago I had a vague inkling of a machine—”

“To travel through Time!” exclaimed the Very Young Man.

“That shall travel indifferently in any direction of Space and Time, as the driver determines.”

Filby contented himself with laughter.

“But I have experimental verification,” said the Time Traveller.

“It would be remarkably convenient for the historian,” the Psychologist suggested. “One might travel back and verify the accepted account of the Battle of Hastings, for instance!”

“Don’t you think you would attract attention?” said the Medical Man. “Our ancestors had no great tolerance for anachronisms.”

“One might get one’s Greek from the very lips of Homer and Plato,” the Very Young Man thought.

“In which case they would certainly plough you for the Little-go. The German scholars have improved Greek so much.”

“Then there is the future,” said the Very Young Man. “Just think! One might invest all one’s money, leave it to accumulate at interest, and hurry on ahead!”

“To discover a society,” said I, “erected on a strictly communistic basis.”

“Of all the wild extravagant theories!” began the Psychologist.

“Yes, so it seemed to me, and so I never talked of it until—”

“Experimental verification!” cried I. “You are going to verify that?”

“The experiment!” cried Filby, who was getting brain-weary.

“Let’s see your experiment anyhow,” said the Psychologist, “though it’s all humbug, you know.”

The Time Traveller smiled round at us. Then, still smiling faintly, and with his hands deep in his trousers pockets, he walked slowly out of the room, and we heard his slippers shuffling down the long passage to his laboratory.

The Psychologist looked at us. “I wonder what he’s got?”

“Some sleight-of-hand trick or other,” said the Medical Man, and Filby tried to tell us about a conjuror he had seen at Burslem, but before he had finished his preface the Time Traveller came back, and Filby’s anecdote collapsed.

The thing the Time Traveller held in his hand was a glittering metallic framework, scarcely larger than a small clock, and very delicately made. There was ivory in it, and some transparent crystalline substance. And now I must be explicit, for this that follows—unless his explanation is to be accepted—is an absolutely unaccountable thing. He took one of the small octagonal tables that were scattered about the room, and set it in front of the fire, with two legs on the hearthrug. On this table he placed the mechanism. Then he drew up a chair, and sat down. The only other object on the table was a small shaded lamp, the bright light of which fell upon the model. There were also perhaps a dozen candles about, two in brass candlesticks upon the mantel and several in sconces, so that the room was brilliantly illuminated. I sat in a low arm-chair nearest the fire, and I drew this forward so as to be almost between the Time Traveller and the fireplace. Filby sat behind him, looking over his shoulder. The Medical Man and the Provincial Mayor watched him in profile from the right, the Psychologist from the left. The Very Young Man stood behind the Psychologist. We were all on the alert. It appears incredible to me that any kind of trick, however subtly conceived and however adroitly done, could have been played upon us under these conditions.