whistling were mechanically produced, this test would have made evident
to me the working of the machinery, if there were any such concealed
within the walls. It certainly was an up-to-date method of examination,
as you must allow.

"Of course, I did not think that any of Tassoc's rivals had fixed up any
mechanical contrivance; but I thought it just possible that there had
been some such thing for producing the whistling, made away back in the
years, perhaps with the intention of giving the room a reputation that
would ensure its being free of inquisitive folk. You see what I mean?
Well, of course, it was just possible, if this were the case, that
someone knew the secret of the machinery, and was utilizing the knowledge
to play this devil of a prank on Tassoc. The microphone test of the walls
would certainly have made this known to me, as I have said; but there was
nothing of the sort in the castle; so that I had practically no doubt at
all now, but that it was a genuine case of what is popularly termed
'haunting.'

"All this time, every night, and sometimes most of each night, the
hooning whistling of the Room was intolerable. It was as if an
intelligence there knew that steps were being taken against it, and piped
and hooned in a sort of mad, mocking contempt. I tell you, it was as
extraordinary as it was horrible. Time after time, I went
along--tiptoeing noiselessly on stockinged feet--to the sealed door (for
I always kept the Room sealed). I went at all hours of the night, and
often the whistling, inside, would seem to change to a brutally malignant
note, as though the half-animate monster saw me plainly through the shut
door. And all the time the shrieking, hooning whistling would fill the
whole corridor, so that I used to feel a precious lonely chap, messing
about there with one of Hell's mysteries.