Astronomical Instruments of the Imperial Observatory

An architectural or surveying instrument plate. The upper portion of the engraving depicts a large, triangular surveying or drafting instrument composed of three graduated wooden beams. Two beams form an inverted 'V' shape, joined at the apex by a wing-nut screw mechanism and a plumb bob hanging vertically. These beams are mounted onto a horizontal base beam, also graduated, with wing-nut sliders at the points of intersection. The instrument is set against a landscape background featuring a horizon line and stylized trees or bushes. The lower portion of the engraving shows the individual components of the device: a single graduated beam shown in perspective, featuring a central groove and numerical markings; a metal plumb bob with a threaded top; a circular washer or nut; and a wing-nut or specialized clamping screw. The entire illustration is enclosed within a simple rectangular border.