Wooden Rule

Object Detail

About This Object
A wooden scale rule inscribed with scales on both sides. Light brown wooden ruler, marked with numbers along top and bottom, metal nail on bottom, slide scale line along the side, both ends damaged. Metal end protector. Excavated on 15 July 1986.

This rule may be a simple 18-inch folding ruler with an astro-navigation sector capability or a variation to the 17th Century Gunter ruler or a sector. A number of scales are inscribed upon the instrument which allow mathematical and trigonometrical calculations to be determined. The two sector lines radiate out from the hinge pivot point. One of the two radial lines has an Aries symbol and ‘P and S’ that may stand for Polaris and the Sun. Two other letters ‘MH’ remain a mystery. Besides the logarithmic scales, there is a small regular spaced scale using even numbers at regular intervals from 28 to what would have been 14 if the brass hinge remained in place the other arm would have had a similar scale from 14 to 0, suggesting that it represented a lunar month and would be used as a scale to set dividers. It is possible that it was connected with the rule’s ‘1Q, 2Q and 3Q’ representing the first, second and third quarters of the moon. On side 2, there are two logarithmic scales and a numerical matrix whose purpose is not known.
Catalogue Number
Height: 213mm
Width: 19mm
Depth: 6mm (1/4")
Production Date
Pre 1758
Production Period
Eighteenth Century