'I promise,' said Miss Abbey.

'It was on the night when the Harmon murder was found out, through
father, just above bridge. And just below bridge, as we were sculling
home, Riderhood crept out of the dark in his boat. And many and many
times afterwards, when such great pains were taken to come to the bottom
of the crime, and it never could be come near, I thought in my own
thoughts, could Riderhood himself have done the murder, and did he
purposely let father find the body? It seemed a'most wicked and cruel
to so much as think such a thing; but now that he tries to throw it upon
father, I go back to it as if it was a truth. Can it be a truth? That
was put into my mind by the dead?'

She asked this question, rather of the fire than of the hostess of the
Fellowship Porters, and looked round the little bar with troubled eyes.

But, Miss Potterson, as a ready schoolmistress accustomed to bring her
pupils to book, set the matter in a light that was essentially of this
world.

'You poor deluded girl,' she said, 'don't you see that you can't open
your mind to particular suspicions of one of the two, without opening
your mind to general suspicions of the other? They had worked together.
Their goings-on had been going on for some time. Even granting that it
was as you have had in your thoughts, what the two had done together
would come familiar to the mind of one.'

'You don't know father, Miss, when you talk like that. Indeed, indeed,
you don't know father.'