CHAPTER I. Introduction

The Time Traveller (for so it will be convenient to speak of him) wasrnexpounding a recondite matter to us. His pale grey eyes shone andrntwinkled, and his usually pale face was flushed and animated. The firernburnt brightly, and the soft radiance of the incandescent lights in thernlilies of silver caught the bubbles that flashed and passed in ourrnglasses. Our chairs, being his patents, embraced and caressed us ratherrnthan submitted to be sat upon, and there was that luxuriousrnafter-dinner atmosphere, when thought runs gracefully free of therntrammels of precision. And he put it to us in this way—marking thernpoints with a lean forefinger—as we sat and lazily admired hisrnearnestness over this new paradox (as we thought it) and his fecundity.rnrn“You must follow me carefully. I shall have to controvert one or twornideas that are almost universally accepted. The geometry, for instance,rnthey taught you at school is founded on a misconception.”rnrn“Is not that rather a large thing to expect us to begin upon?” saidrnFilby, an argumentative person with red hair.rnrn“I do not mean to ask you to accept anything without reasonable groundrnfor it. You will soon admit as much as I need from you. You know ofrncourse that a mathematical line, a line of thickness _nil_, has no realrnexistence. They taught you that? Neither has a mathematical plane.rnThese things are mere abstractions.”rnrn“That is all right,” said the Psychologist.rnrn“Nor, having only length, breadth, and thickness, can a cube have arnreal existence.”rnrn“There I object,” said Filby. “Of course a solid body may exist. Allrnreal things—”rnrn“So most people think. But wait a moment. Can an _instantaneous_ cubernexist?”rnrn“Don’t follow you,” said Filby.rnrn“Can a cube that does not last for any time at all, have a realrnexistence?”rnrnFilby became pensive. “Clearly,” the Time Traveller proceeded, “anyrnreal body must have extension in _four_ directions: it must havernLength, Breadth, Thickness, and—Duration. But through a naturalrninfirmity of the flesh, which I will explain to you in a moment, wernincline to overlook this fact. There are really four dimensions, threernwhich we call the three planes of Space, and a fourth, Time. There is,rnhowever, a tendency to draw an unreal distinction between the formerrnthree dimensions and the latter, because it happens that ourrnconsciousness moves intermittently in one direction along the latterrnfrom the beginning to the end of our lives.”rnrn“That,” said a very young man, making spasmodic efforts to relight hisrncigar over the lamp; “that . . . very clear indeed.”rnrn“Now, it is very remarkable that this is so extensively overlooked,”rncontinued the Time Traveller, with a slight accession of cheerfulness.“Really this is what is meant by the Fourth Dimension, though somernpeople who talk about the Fourth Dimension do not know they mean it. Itrnis only another way of looking at Time. _There is no difference betweenrnTime and any of the three dimensions of Space except that ourrnconsciousness moves along it_. But some foolish people have got hold ofrnthe wrong side of that idea. You have all heard what they have to sayrnabout this Fourth Dimension?”rnrn“_I_ have not,” said the Provincial Mayor.rnrn“It is simply this. That Space, as our mathematicians have it, isrnspoken of as having three dimensions, which one may call Length,rnBreadth, and Thickness, and is always definable by reference to threernplanes, each at right angles to the others. But some philosophicalrnpeople have been asking why _three_ dimensions particularly—why notrnanother direction at right angles to the other three?—and have evenrntried to construct a Four-Dimensional geometry. Professor Simon Newcombrnwas expounding this to the New York Mathematical Society only a monthrnor so ago. You know how on a flat surface, which has only tworndimensions, we can represent a figure of a three-dimensional solid, andrnsimilarly they think that by models of three dimensions they couldrnrepresent one of four—if they could master the perspective of thernthing. See?”rnrn“I think so,” murmured the Provincial Mayor; and, knitting his brows,rnhe lapsed into an introspective state, his lips moving as one whornrepeats mystic words. “Yes, I think I see it now,” he said after somerntime, brightening in a quite transitory manner.rnrn“Well, I do not mind telling you I have been at work upon this geometryrnof Four Dimensions for some time. Some of my results are curious. Forrninstance, here is a portrait of a man at eight years old, another atrnfifteen, another at seventeen, another at twenty-three, and so on. Allrnthese are evidently sections, as it were, Three-Dimensionalrnrepresentations of his Four-Dimensioned being, which is a fixed andrnunalterable thing.rnrn“Scientific people,” proceeded the Time Traveller, after the pausernrequired for the proper assimilation of this, “know very well that Timernis only a kind of Space. Here is a popular scientific diagram, arnweather record. This line I trace with my finger shows the movement ofrnthe barometer. Yesterday it was so high, yesterday night it fell, thenrnthis morning it rose again, and so gently upward to here. Surely thernmercury did not trace this line in any of the dimensions of Spacerngenerally recognised? But certainly it traced such a line, and thatrnline, therefore, we must conclude, was along the Time-Dimension.”rnrn“But,” said the Medical Man, staring hard at a coal in the fire, “ifrnTime is really only a fourth dimension of Space, why is it, and why hasrnit always been, regarded as something different? And why cannot we movernin Time as we move about in the other dimensions of Space?”rnrnThe Time Traveller smiled. “Are you so sure we can move freely inrnSpace? Right and left we can go, backward and forward freely enough,rnand men always have done so. I admit we move freely in two dimensions.rnBut how about up and down? Gravitation limits us there.”rnrn“Not exactly,” said the Medical Man. “There are balloons.”rnrn“But before the balloons, save for spasmodic jumping and therninequalities of the surface, man had no freedom of vertical movement.”rnrn“Still they could move a little up and down,” said the Medical Man.rnrn“Easier, far easier down than up.”rnrn“And you cannot move at all in Time, you cannot get away from thernpresent moment.”rnrn“My dear sir, that is just where you are wrong. That is just where thernwhole world has gone wrong. We are always getting away from the presentrnmoment. Our mental existences, which are immaterial and have norndimensions, are passing along the Time-Dimension with a uniformrnvelocity from the cradle to the grave. Just as we should travel _down_rnif we began our existence fifty miles above the earth’s surface.”rnrn“But the great difficulty is this,” interrupted the Psychologist. ’Yourn_can_ move about in all directions of Space, but you cannot move aboutrnin Time.”rnrn“That is the germ of my great discovery. But you are wrong to say thatrnwe cannot move about in Time. For instance, if I am recalling anrnincident very vividly I go back to the instant of its occurrence: Irnbecome absent-minded, as you say. I jump back for a moment. Of coursernwe have no means of staying back for any length of Time, any more thanrna savage or an animal has of staying six feet above the ground. But arncivilised man is better off than the savage in this respect. He can gornup against gravitation in a balloon, and why should he not hope thatrnultimately he may be able to stop or accelerate his drift along thernTime-Dimension, or even turn about and travel the other way?”rnrn“Oh, _this_,” began Filby, “is all—”rnrn“Why not?” said the Time Traveller.rnrn“It’s against reason,” said Filby.rnrn“What reason?” said the Time Traveller.rnrn“You can show black is white by argument,” said Filby, “but you willrnnever convince me.”rnrn“Possibly not,” said the Time Traveller. “But now you begin to see thernobject of my investigations into the geometry of Four Dimensions. Longrnago I had a vague inkling of a machine—”rnrn“To travel through Time!” exclaimed the Very Young Man.rnrn“That shall travel indifferently in any direction of Space and Time, asrnthe driver determines.”rnrnFilby contented himself with laughter.rnrn“But I have experimental verification,” said the Time Traveller.rnrn“It would be remarkably convenient for the historian,” the Psychologistrnsuggested. “One might travel back and verify the accepted account ofrnthe Battle of Hastings, for instance!”rnrn“Don’t you think you would attract attention?” said the Medical Man.“Our ancestors had no great tolerance for anachronisms.”rnrn“One might get one’s Greek from the very lips of Homer and Plato,” thernVery Young Man thought.rnrn“In which case they would certainly plough you for the Little-go. ThernGerman scholars have improved Greek so much.”rnrn“Then there is the future,” said the Very Young Man. “Just think! Onernmight invest all one’s money, leave it to accumulate at interest, andrnhurry on ahead!”rnrn“To discover a society,” said I, “erected on a strictly communisticrnbasis.”rnrn“Of all the wild extravagant theories!” began the Psychologist.rnrn“Yes, so it seemed to me, and so I never talked of it until—”rnrn“Experimental verification!” cried I. “You are going to verify _that_?”rnrn“The experiment!” cried Filby, who was getting brain-weary.rnrn“Let’s see your experiment anyhow,” said the Psychologist, “though it’srnall humbug, you know.”rnrnThe Time Traveller smiled round at us. Then, still smiling faintly, andrnwith his hands deep in his trousers pockets, he walked slowly out ofrnthe room, and we heard his slippers shuffling down the long passage tornhis laboratory.rnrnThe Psychologist looked at us. “I wonder what he’s got?”rnrn“Some sleight-of-hand trick or other,” said the Medical Man, and Filbyrntried to tell us about a conjuror he had seen at Burslem, but before hernhad finished his preface the Time Traveller came back, and Filby’srnanecdote collapsed.