Brass folding rule, made by Michael Butterfield, Paris, 1680-1699. Signed 'Butterfield A Paris'.

This rule is typical of French instrument sets of the period and is marked in French inches 1-12 on one side, the first and last inches divided in 12 “lignes” numbered 3-6-9-12 with the inscription “Pied de Roy” and an interlaced decor. The other side is engraved with the signature “Butterfield AParis” and two interlaced decors. Thanks to the presence of a mobile arm, this rule can also be used as a level (with a plumb-line we can fixed thanks to the hole near the hinge).