'But,' said the Medical Man, staring hard at a coal in the fire, 'if Time is really only a fourth dimension of Space, why is it, and why has it always been, regarded as something different? And why cannot we move in Time as we move about in the other dimensions of Space?'
The Time Traveller smiled. 'Are you sure we can move freely in Space? Right and left we can go, backward and forward freely enough, and men always have done so. I admit we move freely in two dimensions. But how about up and down? Gravitation limits us there.'
'Not exactly,' said the Medical Man. 'There are balloons.'
'But before the balloons, save for spasmodic jumping and the inequalities of the surface, man had no freedom of vertical movement.'
'Still they could move a little up and down,' said the Medical Man.
'Easier, far easier down than up.'
'And you cannot move at all in Time, you cannot get away from the present moment.'
'My dear sir, that is just where you are wrong. That is just where the whole world has gone wrong. We are always getting away from the present moment. Our mental existences, which are immaterial and have no dimensions, are passing along the Time-Dimension with a uniform velocity from the cradle to the grave. Just as we should travel down if we began our existence fifty miles above the earth's surface.'
'But the great difficulty is this,' interrupted the Psychologist. 'You can move about in all directions of Space, but you cannot move about in Time.'
'That is the germ of my great discovery. But you are wrong to say that we cannot move about in Time. For instance, if I am recalling an incident very vividly I go back to the instant of its occurrence: I become absent-minded, as you say. I jump back for a moment. Of course we have no means of staying back for any length of Time, any more than a savage or an animal has of staying six feet above the ground. But a civilized man is better off than the savage in this respect. He can go up against gravitation in a balloon, and why should he not hope that ultimately he may be able to stop or accelerate his drift along the Time-Dimension, or even turn about and travel the other way?'
'Oh, this,' began Filby, 'is all—'
'Why not?' said the Time Traveller.
'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.
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.