lifted his round face and said: "What do you mean?"

The man of science had picked up the peculiar dagger-sword
from the carpet and was examining it intently as he answered:

"Because you find Mr Todhunter tied up," he said, "you all jump
to the conclusion that Mr Glass had tied him up; and then, I suppose,
escaped. There are four objections to this: First, why should a gentleman
so dressy as our friend Glass leave his hat behind him, if he left
of his own free will? Second," he continued, moving towards the window,
"this is the only exit, and it is locked on the inside. Third, this
blade here has a tiny touch of blood at the point, but there is
no wound on Mr Todhunter. Mr Glass took that wound away with him,
dead or alive. Add to all this primary probability.
It is much more likely that the blackmailed person would try to kill
his incubus, rather than that the blackmailer would try to kill
the goose that lays his golden egg. There, I think, we have
a pretty complete story."

"But the ropes?" inquired the priest, whose eyes had remained
open with a rather vacant admiration.

"Ah, the ropes," said the expert with a singular intonation.
"Miss MacNab very much wanted to know why I did not set Mr Todhunter
free from his ropes. Well, I will tell her. I did not do it because
Mr Todhunter can set himself free from them at any minute he chooses."

"What?" cried the audience on quite different notes of astonishment.

"I have looked at all the knots on Mr Todhunter," reiterated Hood