This calculating device was invented by the same John Napier who invented logarithms (1, 2).

See (1) for a Java simulator.

Notes

1. Alexandros Diploudis, "Undusting Napier's Bones," http://www.macs.hw.ac.uk/~greg/calculators/napier/index.html (Heriot-Watt University, 1997, accessed 2004 Sep 16). From Scott Haman 2002-09-18. This page links to a Java simulator of Napier's bones and to historical background information.

2. Michael R. Williams, "Early Calculations," Chap. 1 in Computing Before Computers (Ames, IA: Iowa State University Press, 1990). Also available online at http://www.computerhistory.org/collections/DocumentArchive/Documents/Books/Computing Before Computers/CBC-Ch-02.pdf (Computer History Museum, accessed 2003 Mar 19).