Description

Rectangular 6 in scale / protractor in ivorine (celluloid) with UK military broad arrow insignia.

The protractor is exactly 6” x 2”. The original design was made for the military, and many were made in boxwood and also in brass for army use in the First World War. It was known as the A II. The protractor rectangular 6 inch ivorine ‘A’ Mk IV was a later design, patent application 361012/30. The design continued to be produced in PVC without reinforcement into the 1970s by Blundell Harling.

Some of these scale / protractors were made with a metal core and this could affect compass bearings. This example has no metal core.

The scales on one side, from top to bottom are: yards 1 inch = 1 mile; yards ¼ inch = 1 mile; miles ¼ inch = 1 mile; miles ¼ inch = 1 mile; yards 1:20,000; metres ¼ inch = 1 mile; metres 1 inch = 1 mile. On the other side below the protractor scales are: metres 1:80,000; metres 1:25,000; miles 1:250,000; yards 1:250,000; yards 1:50,000; yards 1:25,000.