Description

This instrument is one of the earliest examples of a fine swing double arm geared protractor I have seen. Thanks to the invention of the dividing engine, this instrument has a fully divided 360 degree outer ring (internally and externally to within one degree) and an additional vernier (+ or – 15 degrees) giving readings to a tenth of a degree. For the era, spectacular accuracy.

16 cm. in diameter (over 6 inches), original lacquer, blueing of the springs on the triangular arms with pins intact. Signed Ramsden, London in flowing script on the bridge with center crossed etched glass intact. Wear to outer edge from use but all of the teeth are intact and the gearing operates smoothly after two centuries. Amazing early construction (later versions had internal gearing) with machining tolerances down to the thousandths of an inch. A finer and earlier example you will not see for some time. 90% lacquer coverage. Untouched. No bruised screws. No case.