Small rules of Genaille-Lucas

The small rules of Genaille or small rules of Genaille-Lucas constitute an improvement of the Bâtons of Napier. Like they, it acts of a abacus facilitating the calculation of the products and divisions.

These small rules result from a theoretical proposal of the mathematician Edouard Lucas that the engineer of the Armament Henri Genaille managed to implement in 1885.

The small rules of Genaille themselves make it possible to calculate the products by carrying out less additions than by the only use of the sticks of Napier. They are engraved arrows to be followed for the reading, intelligently laid out. One finds by direct reading the result of a number to several figures by a number with a figure.

There exist also small rules facilitating the calculation of the divisions, called small rules multisectrices , and based on the same principle.

See too

Internal bonds

External sites

  • Representation of the small rules of Genaille and text on the sticks to be multiplied (pdf), on culture maths

  • multiplicative small rules and the small rules multisectrices of Genaille and Lucas
  • Collection of calculating machines and plays given by Edouard Lucas to CNAM (bond towards a database).

Random links:Gevrey-Chambertin | Department of Susques | Marcantonio Raimondi | Roberto Bisconti | Zhang Yang | Vauville,_Calvados