From The St. Louis Makers of Surveying Instruments Since 1830:
"Along with the tremendous influx of German immigrants also came a small cadre of master craftsmen. Names like Ryhiner, Blattner, Winzer, Wuger, Holske and Werne were to become the early instrument makers in St. Louis. The principal mainstay of the instrument makers’ trade in the first half of the 19th century was the surveyor’s compass."
A diagram of Blattner's Hinged Standards: