NONIUS

A name frequently given to that useful contrivance,the vernier, for subdividing the divisions of graduated arcs or scales into minute parts, from its invention having been erroneously ascribed to Pedro Nunez, or Nonius, a Portuguese, who lived in the early part of the 16th century. The contrivance employed by Nonius was widely different from the vernier now universally used. It consisted in describing within the same quadrant 45 concentric arcs, dividing the outermost into 90 3equalG parts, the next into 89, the [s. 847]