"What on earth has that to do with it?" I ejaculated.
"My dear Watson, you as a medical man are continually gaining light as to the tendencies of a child by the study of the parents. Don't you see that the converse is equally valid. I have frequently gained my first real insight into the character of parents by studying their children. This child's disposition is abnormally cruel, merely for cruelty's sake, and whether he derives this from his smiling father, as I should suspect, or from his mother, it bodes evil for the poor girl who is in their power."
"I am sure that you are right, Mr. Holmes," cried our client. "A thousand things come back to me which make me certain that you have hit it. Oh, let us lose not an instant in bringing help to this poor creature."
"We must be circumspect, for we are dealing with a very cunning man. We can do nothing until seven o'clock. At that hour we shall be with you, and it will not be long before we solve the mystery."
We were as good as our word, for it was just seven when we reached the Copper Beeches, having put up our trap at a wayside public-house. The group of trees, with their dark leaves shining like burnished metal in the light of the setting sun, were sufficient to mark the house even had Miss Hunter not been standing smiling on the door-step.
"Have you managed it?" asked Holmes.
A loud thudding noise came from somewhere downstairs. "That is Mrs. Toller in the cellar," said she. "Her husband lies snoring on the kitchen rug. Here are his keys, which are the duplicates of Mr. Rucastle's."
"You have done well indeed!" cried Holmes with enthusiasm. "Now lead the way, and we shall soon see the end of this black business."
We passed up the stair, unlocked the door, followed on down a passage, and found ourselves in front of the barricade which Miss Hunter had described. Holmes cut the cord and removed the transverse bar. Then he tried the various keys in the lock, but without success. No sound came from within, and at the silence Holmes' face clouded over.
"I trust that we are not too late," said he. "I think, Miss Hunter, that we had better go in without you. Now, Watson, put your shoulder to it, and we shall see whether we cannot make our way in."
It was an old rickety door and gave at once before our united strength. Together we rushed into the room. It was empty. There was no furniture save a little pallet bed, a small table, and a basketful of linen. The skylight above was open, and the prisoner gone.