Object Name: geometrical square
Dimensions: 25.3 x 18.2 x 2.6 cm (9 15/16 x 7 3/16 x 1 in.)
Description: This square is made of two fixed sights and two rotating sights on an alidade. On the outer edge of the instrument, the outermost graduated line is divided in 10 and goes from 0-200-0. The middle one is a graduated line that goes from 0-20-0 and is divided in units. The inner most graduated line is divided in 5 and goes from 0-100-0. All these are not degrees, but rather the common divisions of Renaissance engineering.
n the center of the instrument there is also a set of concentric circles engraved inside a square. The instrument is supported by four ball-shaped feet. Two openings (like church-windows) were meant to be used with a plumb line (missing) for levelling purposes when the square was oriented in the vertical position–to make altitude and height measurements.
Signed: in circle at the center: IOANNES**LOMBARDELLVS**CASTELLANVS**MASSE
Inscribed: punched on upper and right sides of square: *QVADRATVM**GEOMETRICVM*
punched at the top of center circle: 1559
punched on alidade: *LINEA*FIDVCIAE*ET*REGVLA*ILLE*GRADVS*
Function: A Renaissance engineering instrument to make angle measurements in the horizontal as well as in the vertical position. A pair of dividers and a plumb line were commonly used with such an instrument.
Curatorial Remarks: XRF analysis of the metals was done by Katherine Eremin and Sara Schechner in August 2007.
Published References: Eva Koleva Timothy, Lost in Learning: The Art of Discovery (Newburyport, MA: Athenaeum Publishing, 2010).