Four-Point Compasses
From Inventions
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- Museo Galileo, Institute and Museum of the History of Science, Florence <br> | - Museo Galileo, Institute and Museum of the History of Science, Florence <br> | ||
| - | [http:// | + | [http://catalogue.museogalileo.it/object/FourpointProportionalCompasses.html Florence, Museo Galileo. Istituto di Storia della Scienza, inv. 3567] <br /> |
Current revision as of 14:09, 7 September 2010
Name currently used for the reduction compasses.
Description
Also called double compasses or "compass with double points" (Muzio Oddi, Fabbrica et uso del compasso polimetro [Construction and operation of the polymeter compass] Milan 1633, introduction), the instrument was used as a proportional compasses, for measuring simple proportional ratios, or as a reduction compasses to enlarge or reduce drawings. The compass was composed of two intersecting legs with points on all ends and a fixed or variable pivot depending on the proportional ratios desired. Ancient examples of this instrument have been found in the excavations of Pompeii.
Existing Instruments
- Museo Galileo, Institute and Museum of the History of Science, Florence
Florence, Museo Galileo. Istituto di Storia della Scienza, inv. 3567
Author of the entry: Filippo Camerota
