501 of 520
Sorted by:
Instrument type

Triangulation Instrument
Signed by Jost Bürgi
circa 1600; German
Gilt brass; 324 mm in length (baseline arm)

Two arms are linked by a two-leaf flat hinge. Each has a linear scale [0] to 300, divided to 10, subdivided to 2 with alternate mirror gilding and to 1, numbered by 10. The 'baseline' arm has the final subdivision not on the edge but to coincides with the index of a sliding mount for the third arm, which moves on a pivot carried by this mount and with the same scale extended to 430. The final division to 1 on the arm on the fixed pivot is on the horizontal face of a right-angle edge; for the arm on the sliding pivot, the division to 2 is on a bevelled face, while that to 1 is on a final short vertical edge, so as to be able to define precisely the intersection of the two pivoted scales. Each arm has two blued-steel sights: two slit sights on the baseline arm, one slit and one upright plane sight on the pivoted arms.

Underneath the baseline arm is a scale of 12 inches 'EIN SCHVCH', the first inch, marked 'ZOLL', is undivided, subsequent inches are divided to 2, 3, 4, etc parts to 12, numbered by 1. Signed: 'Iost B[ubar]rgi F' and engraved with the name of an owner 'Alberto Marchoni'

Underneath the arm on the fixed pivot are three gunnery scales, 'STEIN', 1 to 60 decreasing, divided to 5, subdivided to 1, numbered by 5; 'GOSSEN EISEN', 1 to 125, similarly divided; and 'BLEI', 1 to 125 decreasing, similarly divided. A short fourth scale is partly covered by a brass end piece.

See: B. Bramer, Bericht zu M. Jobsten Burgi seligen geometrischen triangular Instruments (Kassel, 1648) and J. Bennett and S. Johnston, The Geometry of War 1500-1750 (Oxford, 1996).

Jim Bennett

Museum of the History of Science, Oxford
Inventory number 54181

© Museum of the History of Science, Oxford. All rights reserved. Information and images provided here may not be reproduced in any form or by any means without the prior written permission of the museum.

Basic URL:

|| Introduction || Essay || Museums || Bibliography || Conventions || Credits || Privacy || Help ||
|Catalogue entries |Handlist || Makers || Places || Articles || Glossary || Search || Home ||