'What became of the cheap paper?' I asked.

'I don't know.'

'I think,' said I, 'we are on the track of the mystery. I believe that
paper covers a sliding panel or concealed door.'

'It is very likely,' replied the earl. 'I intended to have the paper
off, but I had no money to pay a workman, and I am not so industrious
as was my uncle. What is your remaining account?'

'The last also pertains to paper, but comes from a firm in Budge Row,
London, E.C. He has had, it seems, a thousand sheets of it, and it
appears to have been frightfully expensive. This bill is also
illegible, but I take it a thousand sheets were supplied, although of
course it may have been a thousand quires, which would be a little
more reasonable for the price charged, or a thousand reams, which
would be exceedingly cheap.'

'I don't know anything about that. Let's turn on Higgins.'

Higgins knew nothing of this last order of paper either. The wallpaper
mystery he at once cleared up. Apparently the old earl had discovered
by experiment that the heavy, expensive wallpaper would not stick to
the glossy panelling, so he had purchased a cheaper paper, and had
pasted that on first. Higgins said he had gone all over the panelling
with a yellowish-white paper, and after that was dry, he pasted over
it the more expensive rolls.

'But,' I objected, 'the two papers were bought and delivered at the
same time; therefore, he could not have found by experiment that the
heavy paper would not stick.'

'I don't think there is much in that,' commented the earl; 'the heavy
paper may have been bought first, and found to be unsuitable, and then
the coarse, cheap paper bought afterwards. The bill merely shows that
the account was sent in on that date. Indeed, as the village of
Chizelrigg is but a few miles away, it would have been quite possible
for my uncle to have bought the heavy paper in the morning, tried it,
and in the afternoon sent for the commoner lot; but in any case, the
bill would not have been presented until months after the order, and
the two purchases were thus lumped together.'

I was forced to confess that this seemed reasonable.

Now, about the book ordered from Denny's. Did Higgins remember
anything regarding it? It came four years ago.

Ah, yes, Higgins did; he remembered it very well indeed. He had come
in one morning with the earl's tea, and the old man was sitting up in
bed reading his volume with such interest that he was unaware of
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