Genaille’s Rods: An Ingenious Improvement on Napier’s

Extract

In the Mathematics Section of the Science Museum, South Kensington, is a display cabinet that contains many specimens of Napier’s Rods, or Bones. In a corner of the same cabinet are some cardboard “rods” of very different design, expertly made by the Museum staff. Unfortunately they do not form a complete set, nor is their structure immediately obvious, which might account for the fact that they appear to have attracted very little attention. Be that as it may their appearance is certainly intriguing, as a glance at Figure 1 will confirm, and in operation they represent a distinct advance over Napier's rods, on which they are based.