Not many companies make logarithmic scales a feature on their watches, and the most specialized brand to do it is Breitling. This is basically what we most refer it as a slide rule. The circular slide rule has a mobile scale (on a watch, this is on the bidirectional bezel), and a second, fixed scale (on the dial), each with its own graduations. Together they can be used to perform simple mathematical calculations such as multiplications, divisions, conversions and “rule of three” cross-multiplications.
In this video below, Watchfinder & Co. will demonstrate how exactly to use this slide rule for many different reasons and occasions. The featured watch in this video is a Breitling Navitimer 01 LE Black Rotor and the mess of lines and numbers on the dial will be explained.
