The footsteps outside at any given moment were such as one
might hear in any hotel; and yet, taken as a whole, there was
something very strange about them. There were no other footsteps.
It was always a very silent house, for the few familiar guests
went at once to their own apartments, and the well-trained waiters
were told to be almost invisible until they were wanted. One
could not conceive any place where there was less reason to
apprehend anything irregular. But these footsteps were so odd
that one could not decide to call them regular or irregular.
Father Brown followed them with his finger on the edge of the
table, like a man trying to learn a tune on the piano.

First, there came a long rush of rapid little steps, such as a
light man might make in winning a walking race. At a certain
point they stopped and changed to a sort of slow, swinging stamp,
numbering not a quarter of the steps, but occupying about the same
time. The moment the last echoing stamp had died away would come
again the run or ripple of light, hurrying feet, and then again
the thud of the heavier walking. It was certainly the same pair
of boots, partly because (as has been said) there were no other
boots about, and partly because they had a small but unmistakable
creak in them. Father Brown had the kind of head that cannot help
asking questions; and on this apparently trivial question his head
almost split. He had seen men run in order to jump. He had seen
men run in order to slide. But why on earth should a man run in
order to walk? Or, again, why should he walk in order to run?
Yet no other description would cover the antics of this invisible
pair of legs. The man was either walking very fast down one-half
of the corridor in order to walk very slow down the other half; or