Discovery of a Lost Factoring Machine

J. Shallit, H. C. Williams and F. Morain

In this paper, we discuss our discovery of a lost factoring machine, built by a French amateur, E.-O. Carissan, around 1919. The machine was located in the Observatoire de Bordeaux in Floirac, France, where it had been sitting in a drawer for approximately fifty years.

Recently, this machine acquired a new home at the Conservatoire Nationale des Arts et Métiers in Paris.

This paper has appeared in the Mathematical Intelligencer 17 (3) (Summer 1995), 41-47, and a French version in La Revue, No. 14, March 1996.

Click here for additional color pictures of this machine.