Contents: The Thinking Machine --The motor boat --The woman in the case --Dressing room A --Fitting a hypothesis --The crystal gazer --A matter of logic --The interrupted wireless --The midnight message --The Roswell tiara --A fool of good intention --The lost radium --The suit case --The green-eyed monster --Two and two again make four --An opera box --Before midnight --The missing necklace --Master of the profession --The phantom motor --The gap in the trail --The brown coat --A human problem --His perfect alibi --A question of time --The superfluous finger --The case is closed.