Anecdotes: Prototype Fragments from Babbage´s First Difference Engine

The comparison of the various fragments of Babbage´s first difference engine has led the author to conclude that there are intruder parts among the fragments of the Museum of the History of Science in Oxford. Based on a few scant mentions in early descriptions by Babbage, the author believe that some of these fragments belong to Babbage´s 1822 model, in which case this represents a recovery of bits of a missing chapter in the history of calculating machines. This model was the prototype of Babbage´s first difference engine on which work began in 1823, but it was abandoned shortly after the completion of the 1832 demonstration model.