Napier’s Calculating Machines

Cientific renaisance

This small casket is dated to be from the 17th century and was made of verawood with ivory inlays. It is actually a case designed to hold two calculating machines invented by the mathematician John Napier in the second half of the 16th century to perform mathematical calculations with Arabic numerals.

The first device is in the box with a sliding lid, in the upper part of the case. It consists of two plates bearing the tables of powers and rods with the multiples of the amount shown at the end of each rod. The second machine is stored inside the case, in numbered drawers. The central part held the plates with the multiplication tables, which function as the multiplicand, while the side drawers were used to store the perforated pieces used as multipliers when laid across the tables, according to a set of established rules. This second device was capable of performing the multiplications required in certain scientific disciplines, like astronomy and cosmography.