GENAILLE, Henri, and LUCAS Edouard

[Calculating instrument] Les Réglettes Financières, Appareils à Calculs Exacts et Instantanés pour Simplifier les Calculs Financiers et Commerciaux

(Eugène Belin, Paris), 1885

NAPIER'S BONES UPDATED: A PAPER COMPUTER

120 x 181 x 13mm, box with printed label containing eleven rods, printed on all four

sides.

A visually stunning set of ‘Genaille’s Rods’, designed for performing financial calculations,

specifically those having to do with the computation of interest.

The rods have their origin in the work of the mathematician Edouard Lucas, who posed a

mathematical problem to the Académie française. In the course of solving the problem

the engineer Genaille invented this new form of Napier’s Bones, and went on to create a

variety of specific sets.

All such sets are rare, especially complete and in such good condition.

Very good condition: complete; rods very good indeed; light wear to the box edges, and a few marks to the front cover.