Perspectograph by Jobst Bürgi
From Inventions
Has no specific name.
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Inventor
Jobst Bürgi (1552-1632)
Historic Period
ca. 1604
Description
A variant of the theodolite designed mainly to execute topographical views. The instrument is an ingenious mechanism that converts the rotary movements of a diopter into the linear movements of a pen point. The diopter with sights is hinged to the top of a revolving rod and is fixed to a half-disk traversing the base of this rod. A ruler with a pen point on the end also passes through the base of the rod, tangential to the half-disk. The half-disk and the ruler are connected by a wire so that each vertical movement of the diopter is matched by a horizontal sliding motion of the ruler, forwards if the diopter rises, backwards if it lowers. Fixed at the base of the rod, under the drawing board, is another half-disk that rotates when the diopter moves to the right or the left, transmitting its rotary motion to a third half-disk, also positioned under the drawing board. On the latter is a button that slides in a channel on the lower side of the drawing board, so that each rotary motion is matched, through entrainment, by a lateral movement of the drawing board. When the drawing board moves sideways, or when the diopter rotates to the right or left, the pen traces a horizontal line. When the diopter rotates upward or downward instead (the drawing board remains immobile), the pen traces a vertical line.
Bibliographical Resources
Rössler, Guslar. Ein unbekanntes Instrument von Jobst Bürgi im Hessischen Landesmuseum in Kassel, in "Zeitschrift für Instrumentenkunde", 52, 1932, pp. 31-38.
Friess, Peter. Kunst und Maschine. 500 Jahre Maschinenlinien in Bild und Skulptur, Deutscher Kunstverlag, München 1993, pp. 108-110.
Author of the entry: Filippo Camerota
