surveyor's quadrant
Date: 1622
Inventory Number: DW0851
Classification: Surveyor's Quadrant
Subject:
Maker: Adam Heroldt (fl. 1616 - 1649)
Cultural Region:
Place of Origin:
Rome,
Dimensions:
15.4 x 16.7 x 17 cm (6 1/16 x 6 9/16 x 6 11/16 in.)
Description:
This quadrant has two fixed sights on one side and two others on the rotating alidade. The small compass is removable and engraved around it are the eight principal winds in Latin. The outer edge of the quadrant has a graduated line for degrees, with diagonals for precision measurements. The shadow square (umbra recta / umbra versa) is used to measure heights when the instrument is positioned vertically. A ball and socket mounting is screwed to the instrument, so it could be put on a staff or tripod in the field.
In Collection(s)
Signedon the front: Nova inuentio et usus Quadra[n]tis / et bussolae ad in: / uentae ab Adamo / Heroldo Ger / mano cum / Privilegio S[anctissi]mi [Domi]ni / N[ost]ri Papae Gregory / XV Anno / MDCXXII
Inscribedon the front: QVADRANTE ASTRONOMICO
FunctionSuch a quadrant was used to make angle measurements on any plane. Used in surveying, the calculations derived from these measurements is based on the principle of similar triangles (trigonometry).