Colonial Semi-Circumferentor With Engraved Trough Compass

Colonial Semi-Circumferentor With Engraved Trough Compass



Circa 1790

Country of manufacture

North America

Categories: Surveying Instruments & Mining, Engineering antiques


This colonial era unsigned Semi-Circumferentor is one of the more common varieties – trough compass, brass semi-circle, brass alidade  and sight vanes, and a wood block.   The engraved compass card is another story, however.  Wow.  Semi-Circumferentors made largely out of wood were supposed to be a fairly cheap way for a surveyor to buy an instrument that could measure independently of the needle.  So why would an affordable instrument have such a wonderfully engraved compass card???


I came across a fair number of pre-1825 Semi-Circumferentors during my research for my Theodolite and Semi-Circumferentor website addition,  and the Semi-Circumferentor offered here is the only one to have an elaborately engraved compass card.  


If you look closely at the engraving, there appears to be an “M” engraved.  I can also make out a much smaller “L” if I squint hard enough.  These are probably just random scratches.  But there is an “L. M.” who would be capable of this level of engraving – Lewis Michael.   I can’t think of a single reason why Lewis Michael would make this instrument, however.  And he never advertised Semicircles for sale in his newspapers ad.   So I view this as an unsigned but VERY cool Semi-Circumferentor, broken glass notwithstanding.


To see my webpage offering this neat Semi-Circumferentor for sale, please go to: Colonial Semi-Circumferentor.

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US The Compleat Surveyor

The Compleat Surveyor specializes in rare instruments and books related to land surveying. This initially was a family business - my father (F. D. Uzes) was a noted surveyor, collector and author (Illustrated Price Guide To Antique Surveying Instruments and Books - published in 1980). Having spent a lifetime surrounded by old instruments and books, I now run the business myself. I use my website ( to both sell instruments and provide historical information related to land surveying.

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