Antique wooden spirit level (Wasserwaage), cabinetmaker’s precision workshop instrument, Central Europe, circa 1870–1895. Hardwood body with full brass wear plate and one original hand-blown glass vial (horizontal). The vial is permanently bedded and hand-calibrated, typical of pre-industrial measuring instruments before standardized replaceable cartridges around 1900. Side light ports illuminate the vial and the shaped viewing windows act as reference edges for reading the bubble, a characteristic feature of early hand-calibrated levels. The hand-cut slotted screws and flush-mounted brass plate further support 19th-century manufacture. Used in joinery workshops for accurate alignment of furniture and interior fittings rather than construction work. The brass plate provided a stable reference surface and prevented wear of the wooden body. The glass tube shows rounded sealed ends and the bubble centers correctly; the instrument remains functional. Good antique condition with honest workshop wear and patina. No modern alterations observed.