Yes, the signor was in, the girl replied, leading us back into the workshop.  He proved to be a short man with a bland, open face and frank eyes, the very antithesis of his trade.

“I have arranged for a circle with Mrs. May Popper,” began Kennedy, handing the man his card.  “I suppose you know her?”

“Indeed yes,” he answered.  “I furnished her seance room.”

“Well, I want to hire for to-night just the same sort of tables, cabinets, carpets, everything that she has—­only hire, you understand, but I am willing to pay you well for them.  It is the best way to get a good sitting, I believe.  Can you do it?”

The little man thought a moment, then replied:  “Si, signor yes—­ very nearly, near enough.  I would do anything for Mrs. Popper.  She is a good customer.  But her manager—­”

“My friend here, Mr. Jameson, has had seances with her in her own apartment,” interposed Craig.  “Perhaps he can help you to recollect just what is necessary.”

“I know very well, signor.  I have the duplicate bill, the bill which was paid by that Farrington with a check from the banker Vandam.  Leave it to me.”

“Then you will get the stuff together this morning and have it up to my place this afternoon.”

“Yes, Professor, yes.  It is a bargain.  I would do anything for Mrs. Popper—­she is a fine woman.”

Late that afternoon I rejoined Craig at his laboratory.  Signor Marina had already arrived with a truck and was disposing the paraphernalia about the laboratory.  He had first laid a thick black rug.  Mrs. Popper very much affected black carpets, and I had noticed that Vandam’s room was carpeted in black, too.  I suppose black conceals everything that one oughtn’t to see at a seance.

A cabinet with a black curtain, several chairs, a light deal table, several banjos, horns, and other instruments were disposed about the room.  With a few suggestions from me we made a fair duplication of the hangings on the walls.  Kennedy was manifestly anxious to finish, and at last it was done.

After Marina had gone, Kennedy stretched a curtain over the end of the room farthest from the cabinet.  Behind it he placed on a shelf the apparatus composed of the pendulums and magnets.  The beakers and test-tubes were also on this shelf.

He had also arranged that the cabinet should be so situated that it was next a hallway that ran past his laboratory.

“To-night, Jameson,” he said, indicating a spot on the hall wall just back of the cabinet, “I shall want you to bring my guests out here and do a little spirit rapping—­I’ll tell you just what to do when the time comes.”

That night, when we gathered in the transformed laboratory, there were Henry Vandam, Dr. Hanson, Inspector O’Connor, Kennedy, and myself.  At last the sound of wheels was heard, and Mrs. Popper drove up in a hansom, accompanied by Farrington.  They both inspected the room narrowly and seemed satisfied.  I had, as I have said, taken a serious dislike to the man, and watched him closely.  I did not like his air of calm assurance.