This is a fascinating and unique Theodolite that is engraved as a Semicircle - only 180 degrees.

The Theodolite was made by Jean Baptiste Van Lerberghe of Bollezelle, France. Bollezelle is about 11 miles south of Dunkirk and 20 miles west of Belgium border.

I found a Jean Baptiste Van Lerberghe who fits the profile. Born in 1683 and passed away in 1750. He was born, married and died around Bollezeelle (he actually passed away in Bollzeelle). The Theodolite could have been made anytime between say 1698 and 1750. The Theodolite looks both crude and early to my eye. Key early features include the small full brass disc, the small sight vanes with very narrow slits, and the very small orientation compass (looks to be engraved to 180 degrees in 20 degree increments). My best guess is that Van Lerberghe made this Theodolite between 1700 to 1720.

I don't have any info about what Jean Baptiste Van Lerberghe did for living. I suspect he might have been a surveyor and made this Theodolite for his own personal use. I've seen another very early and crude surveying instrument, and that instrument was made and used by a surveyor.

I note that Jean Baptiste Van Lerberghe had a son born in Bollezelle in 1723 - Jean Baptiste Van Lerberghe Jr. In theory Junior could've made the Theodolite as well after his father passed away in 1750. I think the Theodolite is earlier than that. This also puts Jean Baptiste Van Lerberghe Senior in Bollezeele in the early 1720s.

This is a very early, crude and charming instrument.