The banker recoiled in horror. "I should not dream of trying," said he.

"Then I will." Holmes suddenly bent his strength upon it, but without result. "I feel it give a little," said he; "but, though I am exceptionally strong in the fingers, it would take me all my time to break it. An ordinary man could not do it. Now, what do you think would happen if I did break it, Mr. Holder? There would be a noise like a pistol shot. Do you tell me that all this happened within a few yards of your bed and that you heard nothing of it?"

"I do not know what to think. It is all dark to me."

"But perhaps it may grow lighter as we go. What do you think, Miss Holder?"

"I confess that I still share my uncle's perplexity."

"Your son had no shoes or slippers on when you saw him?"

"He had nothing on save only his trousers and shirt."

"Thank you. We have certainly been favoured with extraordinary luck during this inquiry, and it will be entirely our own fault if we do not succeed in clearing the matter up. With your permission, Mr. Holder, I shall now continue my investigations outside."

He went alone, at his own request, for he explained that any unnecessary footmarks might make his task more difficult. For an hour or more he was at work, returning at last with his feet heavy with snow and his features as inscrutable as ever.

"I think that I have seen now all that there is to see, Mr. Holder," said he; "I can serve you best by returning to my rooms."

"But the gems, Mr. Holmes. Where are they?"

"I cannot tell."

The banker wrung his hands. "I shall never see them again!" he cried. "And my son? You give me hopes?"

"My opinion is in no way altered."

"Then, for God's sake, what was this dark business which was acted in my house last night?"

"If you can call upon me at my Baker Street rooms to-morrow morning between nine and ten I shall be happy to do what I can to make it clearer. I understand that you give me carte blanche to act for you, provided only that I get back the gems, and that you place no limit on the sum I may draw."