The mechanical Turk enchanted chess enthusiasts in the late 18th century. Many people really wanted to believe it was an automaton. But there were some who rightly suspected that the Turk was actually manipulated by someone hidden in the cabinet during the performance, although they couldn't prove it.  

Edgar Allan Poe Tried to Solve the Mystery
In his explanation of how the Turk functioned, Edgar Allan Poe came perilously close to the truth: The clockwork mechanism shown to spectators did not extend right to the back of the cabinet; it filled only a third. After the player climbed into the cabinet, he would sit on a sliding seat behind the mechanism. His upper body was hidden by the mechanism and his legs were tucked into the lower section. The chess player could therefore sit up straight. No dwarves or children were abused.  

Empty Cabinet Filled with Cogwheels
When the show began, the operator, in the back of the cabinet, would slide forward on his seat (set on well-oiled rails, it moved to and fro almost silently). He'd then pull his knees up and bend his upper body forwards. Moving the seat shifted a number of superfluous cogwheels into the space behind the clockwork machinery. When the presenter opened the door in the back of the cabinet and illuminated the interior with a candle, spectators had the impression that the entire box was full of complicated machinery. Once the door was shut, the operator could push his seat back again and stretch his legs out. Now the main section had to be prepared for public inspection. The operator sat upright, hid his legs under a hinged flap and put a board in place to hide his upper body as well. Meanwhile the presenter would take his time setting up the chess pieces. Once he was finished, he could open the front doors of the cabinet – which appeared to be empty.  

Candle Smoke Obfuscated by Candelabra
Now that the audience was convinced that no one could possibly be inside the cabinet, the presenter would shut all the doors and noisily wind up the automaton. While he did so, the hidden operator had to reorganize the inside of the cabinet again. There was a little compartment where he could hide a candle to illuminate the interior of the automaton. Smoke from the candle went up a chimney-like tube through the top of the mannequin's turban, and two candelabra, ostensibly used to illuminate the chessboard, served to distract spectators from the smoke and smell of the candle. Although fresh air could get in through little holes in the surface of the Turk, inside the cabinet it must have been so sticky and oppressive that the performance had to be limited to one hour.  

A Complex Lever System Moved the Hand
Inside the cabinet, the operator had a chessboard with two holes drilled in each square. The chess pieces, which had an appropriate peg on the bottom, would be inserted into one of the holes. The second hole was used to position the Turk's arm on the upper chessboard using a pantograph, a complicated system of levers. Using a metal rod that could move to each square of the inner chessboard and was connected by a system of levers to the arm of the Turk, the operator could position the figure's left hand exactly over the appropriate square of the upper chessboard. By moving the rod up and down he could raise and lower the mannequin's hand, and by turning the rod he could open and close its fingers. For every move, the operator first positioned his own chess piece on the desired square, then made the Turk's arm do the same on the upper chessboard.  

Magnets Revealed Moves on the Surface
But how did the hidden player know what moves his opponent had made? The pieces on the upper board contained strong little magnets. Under each square there was a small metal plate which hung from a fine, coiled metal spring. When a chess piece was moved to a particular square, the magnet inside the piece attracted the plate and lifted it up to the roof of the cabinet. If the piece was removed, the plate would fall back down again and jiggle for a few seconds on the spring. The hidden player only had to watch the underside of the upper chessboard to see which piece had been moved. He would duplicate the positions on his own board and consider his next move.