A very unusual cased oxidised brass prismatic surveyors compass, probably by William Cary & Co, c1865

Unusual Prismatic Surveyors Compass c1865


Antique prismatic compass having green card dial with cardinals and intercardinals, the azimuth circle reverse-marked to 360 degrees with stations at 10 degree increments divided to half degrees.

Standard pattern low drum form case. Unusual folding sights comprising slit-type rear, beam-mounted fore of “A” frame construction with sighting wire and very unusually positioned prism. Card brake and lock buttons.

The whole contained within its original fine oxblood pig skin and fish skin over timber, blue velvet lined case. Side mounted swing catches, snap closure on a button release.

The instrument retaining a high proportion of its original oxidised finish, pronounced wear to base with generally fine scratches and minor abrasions overall. The prism un-cracked, sight mountings tight and secure. The card with some distortion, swinging well and easily finding north. Brake and lock working well.

Generally in very good condition, the travel case with colour fading to lid, the base and sides retaining well-saturated colour, all three securing catches present and working. The lid inside with signs of a label having been present. Marks, impressions and abrasions overall.

This is a very unusual pattern, and we have seen only one other before, that an example by Cary c1850. The prism is positioned on the large sighting vane rather than on the opposing side and the card dial, to reflect this, shows 360 degrees at North, rather than the usual 180 degrees seen in standard prismatic compasses. The card also has brass screws at North and South, probably intended to produce a dampening effect to its movement. There are no maker’s marks but the compass is extremely well-engineered, the optics are very fine, and the travel case is of very high quality. The style and design, especially the similarly unusual case, suggest a date of manufacture between 1860-1870.

Very much a collector’s piece.

Dimensions: 4½” wide x 5″ long x 2″ high

Stock No: SI0843

Price: £550

Image of Prismatic Surveying Compass after Barker c1860
Image of Prismatic Surveying Compass after Barker c1860
Image of Prismatic Surveying Compass after Barker c1860
Image of Prismatic Surveying Compass after Barker c1860
Image of Prismatic Surveying Compass after Barker c1860
Image of Prismatic Surveying Compass after Barker c1860
Image of Prismatic Surveying Compass after Barker c1860
Image of Prismatic Surveying Compass after Barker c1860





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