The Time Traveller
         (for so
             it will be convenient
                  to speak of him)
          was expounding a recondite
              matter to us.

    His grey eyes
           shone and twinkled,
         and his usually pale face
            was flushed and animated.

    The fire burned brightly,
           and the soft radiance
               of the
             incandescent
                lights
               in the lilies of silver
              caught the bubbles
             that flashed and
                  passed in our glasses.

    Our chairs,
           being his patents,
         embraced and caressed us
             rather than submitted to be
                 sat upon,
           and there was
             that luxurious after-dinner atmosphere
               when thought
                roams gracefully free
                       of the trammels of precision.

    And he put
           it to us
               in this way
          --marking the points with a
              lean forefinger--as
             we sat and lazily
                  admired his earnestness
                       over this new paradox
         (as we thought it:)
            and his fecundity.

    'You must follow me carefully.

    I shall have
          to controvert one
              or two ideas
         that are almost universally accepted.

    The geometry,
           for instance,
         they taught you at school
            is founded on a misconception.'

    'Is not
         that rather a large thing
              to expect us
                  to begin upon?'

    said Filby,
           an argumentative person
               with red hair.

    'I do not mean
          to ask you
              to accept anything
         without reasonable ground for it.

    You will soon admit
         as much as
             I need from you.

    You know of course
         that a mathematical line,
           a line of thickness NIL,
         has no real existence.

    They taught you that?

    Neither has a mathematical plane.

    These things are mere abstractions.'

    'That is all right,'
          said the Psychologist.

    'Nor,
           having only length,
         breadth,
           and thickness,
         can a cube
              have a real existence.'

    'There I object,' said Filby.

    'Of course a solid body
        may exist.

    All real things
          --'

    'So most people think.

    But wait a moment.

    Can an INSTANTANEOUS cube exist?'

    'Don't follow you,' said Filby.

    'Can a cube
         that does not
              last for any time
                   at all,
           have a real existence?'

    Filby became pensive.

    'Clearly,'
          the Time Traveller proceeded,
               'any real body
                must have extension
                       in FOUR directions:
            it must have Length,
               Breadth,
             Thickness,
               and
              --Duration.

    But through a natural infirmity
           of the flesh,
         which I
            will explain to you
                   in a moment,
         we incline
               to overlook this fact.

    There are really four dimensions,
           three which
             we call the three planes
                   of Space,
         and a fourth,
           Time.

    There is,
           however,
         a tendency
              to draw an unreal distinction
                   between the former three dimensions
                       and the latter,
           because it happens
             that our
                 consciousness
                    moves intermittently
                   in one direction
                 along the latter
                       from the beginning
                           to the end
                               of our lives.'

    'That,'
          said a very young man,
               making spasmodic efforts
                   to relight his cigar
                 over the lamp;
            'that
               . . . very clear indeed.'

    'Now,
           it is very remarkable
             that this
                is so extensively overlooked,'
                      continued the Time Traveller,
      with a slight accession
             of cheerfulness.

    'Really this is
         what is
              meant by the Fourth Dimension,
           though some people
             who talk
                   about the Fourth Dimension
                  do not know
                 they mean it.

    It is
          only another way
               of looking at Time.

  THERE IS NO DIFFERENCE BETWEEN
      TIME AND ANY OF THE
      THREE DIMENSIONS OF