Blast from the Analog Past! Physicist Identifies First Protractor

Blast from the Analog Past! Physicist Identifies First Protractor
Egyptian artifact recently identified as world's first known protractor, via

And now a controversial look back… way back.

Physicist Amelia Sparavigna recently identified an artifact in a Turin museum as the world’s first known protractor. Sparavigna argues that the artifact’s ornate decoration, which resembles a compass rose with 16 evenly spaced petals surrounded by a zigzag with 36 corners, was used in combination with a plumb line to measure the slope angle of an object beneath it.

The artifact was discovered in 1906 by archaeologist Ernesto Schiaparelli in Diar-al-Medina, in the tomb of Egyptian architect Kha. Among Kha’s belongings were cubit rods, a leveling device, and this oddly shaped wooden case with a hinged lid.

Diagram of how Amelia Sparavigna thinks artifact was used, via

The fraction of one-sixteenth features heavily in Egyptian calculus, according to Sparavigna, and they also identified 36 star groups called decans, which later formed the basis of a star clock. She thinks the object was “a protractor instrument with two scales, one based on Egyptian fractions, the other based on decans.”

The identification is apparently inconclusive. In an interview with New Scientist, Kate Spence, a University of Cambridge archaeologist specializing in ancient Egyptian architecture, is not convinced and maintains the object is simply a decorative case. She says that unlike those on other known measuring instruments, the markings in question are not particularly accurate.

Spence certainly has a point about the object’s inaccuracy, but buggy tools are a part of our contemporary practice so who’s to say that the Egyptians didn’t have to deal with these frustrations as well?

From New Scientist:

About this author
Cite: Samuel Jacobson. "Blast from the Analog Past! Physicist Identifies First Protractor" 22 Aug 2011. ArchDaily. Accessed . <> ISSN 0719-8884

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