Who invented the Napier Bones

Napier's bones is a manual calculating tool made up of numbered rods marked with multiplication tables, which a user could arrange side by side to simplify multiplication, division, and even finding square roots. This tool takes its name directly from the Scottish mathematician who designed it in the early 17th century, publishing his method in 1617, and the device is named after him in the same way that many inventions carry the surname of the person who created them.

None of the other names listed have a documented connection to inventing this tool. A person sharing part of the same surname but without a first name matching the historical record is not the mathematician credited with the invention. A different inventor is instead remembered for designing an automated loom controlled by punched cards, a device used in the textile industry rather than in mathematics. Another figure among the choices is known for designing early mechanical calculating engines in the 19th century, considerably later than Napier's bones and using an entirely different mechanical approach based on gears rather than multiplication rods.

A reliable way to answer "who invented" questions about a tool is to match the tool's own name to the inventor's name first, since many historical devices, including this one, are named directly after their creator.