An Improved Drawing Instrument to Facilitate the Plotting of Surveyors Traverses, Drawings, Plans and the like.

摘要

4998. Harvie, R. W. March 1. Protractors.-A rule 3 is adjustably mounted on an annular protractor 1 in such a way that one edge of the rule always passes through the centre of the protractor, which is carried by a series of links 4, 7 secured to the drawing-board by a bar 8, the arrangement being such that the protractor always moves parallel to itself.