'It's against reason,' said Filby.

'What reason?' said the Time Traveller.

'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 conjurer he had seen at Burslem; but before he had finished his preface the Time Traveller came back, and Filby's anecdote collapsed.