Firmly holding it in his own hands, the detective displayed the letter to Mr. Pyecroft—­an odd, foreign hand, the paper of superfine quality, but without crest or any other embossing.  Mr. Pyecroft studied it closely; his look grew puzzled; then he turned to Matilda.

“I don’t exactly remember, Matilda, but it seems to me that there was handwriting like this among the letters you sent to me to keep for you.”

Matilda gaped at Mr. Pyecroft.  Mrs. De Peyster, half-rising on an elbow, peered in amazed stupefaction at her incalculable young man of the sea.

“Why, of course, she’d have turned it over to some one else for safe-keeping!” the detective cried triumphantly.  “Where is it?” he demanded of Mr. Pyecroft.

“I’m not so sure I have it,” said the shallow Mr. Pyecroft apologetically.  “It just seems to me that I saw writing like this.  If I have, it’s over in a little room I keep.  But if I really do have it”—­with the shrewd look of a small mind—­“we couldn’t sell it for fifteen hundred.”

“How much d’you want?”

“Well”—­Mr. Pyecroft hesitated—­“say—­say three thousand.”

“Good God, that’s plain blackmail!”

“It may be, but poor people like us don’t often get a chance like this.”

“I won’t pay it!”

“Perhaps, then,”—­apologetically,—­“we’d better deal with Mrs. Allistair direct.”

“Oh, well,—­if you’ve got the letter, we won’t scrap about the price.  I’ll come across.”

“Cash?” shrewdly queried the doltish brother.

“Sure.  I don’t run no risks with checks.”

“I—­we—­wouldn’t let the letter go out of our hands until it’s paid for.  And we won’t go to any office.  You yourself can say whether it’s what you want or not?  And you can pay right here?”

“Sure.  I’m the judge of what I want.  And when I go for a big thing, I go prepared.”  Mr. Brown opened his coat, and significantly patted a bulge on the right side of his vest.

“Well, then, I’ll go to my room and see if I have it.  But you’ll have to wait here, for”—­again with the shrewd look of the ineffectual man—­“you might follow me, and with some more detectives you might take the letter from me.”

“Soon wait here as anywhere else.  Anyhow, I’ll want your sister’s word,” nodding at Matilda, “that the letter is the same.  But don’t worry—­nobody’s going to take anything from you.”

Mr. Pyecroft started out, then paused.

“I just happened to remember; you said the letter might not be signed.  Hadn’t you better let me have one of the Duke de Crecy’s letters, so I can verify the handwriting?”

“I don’t mind; these don’t tell much.”  And the detective handed over one letter.

“It may be an hour or two before I can get back; the letters are packed away and I’ve got to go through them and compare them.”

He slipped out.  Mr. Brown, as he watched him, could hardly conceal his contempt.