1891 invention that allowed the user to read off the results of simple division problems directly, with no intermediate mental calculations. This set includes 12 wood laser engraved rods stored in the custom box.
In the days before calculators, methods of simplifying calculations were of much interest. In 1617 Napier also published a book describing a method to multiply, divide and extract square roots using a set of bars or rods. These became known as Napier's Bones.
In the late 1800s, Henri Genaille, a French civil engineer, invented an improvement to Napier's Bones that eliminates the need for mental calculations. The problem was posed by Edouard Lucas and thus the alternate name of Genaille-Lucas Rulers (or Rods) .
The process of dividing any integer into a number of any length is reduced to looking up numbers on the rods. Studying how and why these rods work gives real insight into the nature of division.
Made in USA by Creative Crafthouse. We also make on a separate listing the Genaille-Lucas Rods for Multiplication. The video below will show both sets, multipcation and division