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 the Theodolite and Semi-Circumferentor website addition, and the Semi-Circumferentor offered here is the only one (by far) 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.