The Nonius scale is a precision measuring tool used primarily in scientific instruments like calipers and micrometers. It allows users to read measurements more accurately than with standard scales by providing additional divisions. Named after the Portuguese mathematician Nonius, this scale enhances the resolution of measurements, making it easier to determine small differences. The Nonius scale works by aligning a fixed scale with a movable one, where the divisions on the movable scale are slightly offset. This design helps users interpolate between the main scale's markings, improving measurement accuracy in various applications, including engineering and manufacturing.