Slide Rule

Origin:  The development of the slide rule can be contributed to many people.  John Napier composed the principles of logarithms, which are what slide rules are based on.  Edmund Gunter engraved these logarithms on a rule.  However, William Oughtred was the true slide rule inventor, as he was the first person to use a sliding scale.

Composition and use:  The slide rule is a very efficient mechanical calculator.  A slide rule can be used to multiply, divide, exponentiate, take logarithms and perform trigonometric operations to three significant figures more quickly than with an electronic calculator.  There are different types of slide rules such as straight, circular, and cylindrical.

Uses today:  Use of the slide rule quickly depleted after the invention of mechanical calculators.  However, they are still used today to get a better feel for what numbers mean and how to use them.  Slide rules are also widely collected and displayed in museums around the world.