Ruler

This 12inch Boxwood Scale Rule marked 'Elliott Bros London' on one face and the other side is marked 'W.H.U.Smith'.

The centre front of this Boxwood Scale Rule.{the side with maker name} of one Scale is marked: 45 & 35, and the other side marked 20 & 40.

This Rule is part of a set of Marquois Scales which usually would have comprised this Rule, another 12 inch rule with scales marked for 25/50 and 30/60 and a triangle.

Marquois scales were devised by a Captain of that name c. 1780 for use with his system of surveying for military purposes. Equidistant parallel lines could be drawn with speed and accuracy using his special plain-edged scales together with a right-angled triangle. The triangle easily recognizable since it has two plain and one bevelled edge, its angles ensure its hypotenuse is three times the length of its short side and has two sides marked with an index matrix. Sets of these special Marquois scales continued to be made throughout the nineteenth century.
The owner of this Scale Rule was a W.H.U.Smith. The company legend of Elliott Bros London was not used after 1916 as they became a Limited Company so this rule predates that. It would have been nice if the owner had been Mr Willoughby Smith or his son Mr Willoughby Statham Smith who were managers of Elliott Bros London but their initials do not match