Zeměměřické a astronomické přístroje používané na území ČR od 16. do konce 20. století
The Paris based company Lenoir producing mathematical instruments was founded in 1820. In 1827, Gravet-Lenoir became the successor company, and in 1867, Tavernier-Gravet succeeded it. Slide rules were especially well known. The company ceased to exist in 1972.
The manufacturer's name on the device