The Robot

  It was not until the late 1950's that Carlo Pedretti of the Unversity of California proposed that the drawings on the left were for a robot.  Some forty years later the Florence-based Institute and Museum of the History of Science in collaboration with Mark Rosheim, a NASA contractor and expert in robotics, developed a "digital" version of the robot shown on the right.

  There is no evidence that the robot was actually built but it was designed to sit up, turn, bend both arms and legs and to open its mouth or visor, probably to make some kind of noise.  It was dressed in a suit of armour.

  Leonardo may have intended the robot for a festival or celebration of some kind.  At Il Paradiso - a celebration held on 13th January 1490 in Milan - Leonardo was said to have built a model of a mountain crowned by a giant egg which rotated while a fantastic series of automats representing the human race sang the praises of the Sforza family.  The egg finally opened to reveal the seven planets and figures of the Graces, the Virtues, Nymphs, Hermes, Jupiter and Apollo.

The Adding Machine (or Ratio Machine)

  In 1967 American researchers working at the National Library of Spain in Madrid found two unknown works of Leonardo which became known as the Codex Madrid.  It included the drawing on the right.  Leonardo expert Dr Roberto Guatelli saw the drawing and thought it similar to one in the Codex Atlanticus.

  In 1968 Dr Guatelli made a replica from the two drawings using "his own intuition and imagination..." in the process.  The replica was put on display at an IBM exhibition with the following text:

"Device for Calculation: An early version of today's complicated calculator, Leonardo's mechanism maintains a constant ratio of ten to one in each of its 13 digit-registering wheels. For each complete revolution of the first handle, the unit wheel is turned slightly to register a new digit ranging from zero to nine. Consistent with the ten to one ratio, the tenth revolution of the first handle causes the unit wheel to complete its first revolution and register zero, which in turn drives the decimal wheel from zero to one. Each additional wheel marking hundreds, thousands, etc., operates on the same ratio. Slight refinements were made on Leonardo's original sketch to give the viewer a clearer picture of how each of the 13 wheels can be independently operated and yet maintain the ten to one ratio. Leonardo's sketch shows weights to demonstrate the equability of the machine."

  After a year of the machine being on display controversy concerning the reliability of the replica had grown and an academic trial was held at Massachusetts University in an attempt to settle the matter.

  Objectors claimed that the device was a ratio machine - one revolution of the first shaft would give rise to 10 revolutions of the second and so on.  Such a machine would not work due to the amount of friction involved.

  The vote was a tie but IBM removed the replica from the exhibition.