Claudius Ptolemy scientific works discovered

[guy]

Previously unknown Greek works possibly by Claudius Ptolemy, as well as by two others, have been discovered when investigating a palimpsest by multispectral imaging. Looking beneath the later Latin works of Isidore of Seville on three Greek scientific works, six of the fifteen leaves examined are attributed to Ptolemy.

Background information:

Palimpsest is a manuscript in which the original writing on the document has been erased or scraped clean in order to place new writings; nevertheless, the older original writings can still be seen, usually with specialized technological analysis.

Claudius Ptolemy from Egypt (c. AD 100-170) was a Roman mathematician, astronomer, and geologist. Ptolemy explained the geocentric model in which the earth was the center of the universe and the planets, sun, and stars circled the earth.

Isidore of Seville (c. AD 560-636) was a Spanish scholar, theologian, and archbishop of Seville. It was the writings of Isidore over the previous work of possibly Claudius Ptolemy that created the palimpsest.

 

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The sheets in question (palimpsests) were erased in the 8th century, so that the Latin text of the Etymologies of Isidore of Seville could be copied over the erased text. It is thanks to the use of advanced multispectral imaging techniques that their content was discovered and deciphered.

The new text, which has gaps, describes the construction and use of a nine-ringed armillary sphere, identifiable as the "Meteoroscope" invented by the astronomer Claudius Ptolemy. This major discovery sheds new light on the history of astronomy in antiquity and on the beginnings of the history of science. In particular, it provides a better understanding of the scientific method used by ancient astronomers to make their measurements.

Moreover, this discovery illustrates the progress of advanced techniques such as multispectral imaging, whose application to illegible manuscripts makes it possible to save from oblivion texts belonging to the cultural heritage of humanity.

 

https://www.sorbonne-universite.fr/en/presse/discovery-lost-astronomical-treatise-claudius-ptolemy

 

The academic article describing the study:

 

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The eighth-century Latin manuscript Milan, Veneranda Biblioteca Ambrosiana, L 99 Sup. contains fifteen palimpsest leaves previously used for three Greek scientific texts: a text of unknown authorship on mathematical mechanics and catoptrics, known as the Fragmentum Mathematicum Bobiense  (three leaves), Ptolemy's Analemma (six leaves), and an astronomical text that has hitherto remained unidentified and almost entirely unread (six leaves). We report here on the current state of our research on this last text, based on multispectral images. The text, incompletely preserved, is a treatise on the construction and uses of a nine-ringed armillary instrument, identifiable as the “meteoroscope” invented by Ptolemy and known to us from passages in Ptolemy's Geography and in writings of Pappus and Proclus. We further argue that the author of our text was Ptolemy himself.

 

https://link.springer.com/article/10.1007/s00407-022-00302-w

 

(The “Meteoroscope” invented by Ptolemy to explain his geocentric theory on the universe.)

Short video on the Armillary sphere, similar to the “Meteoroscope” described by Ptolemy.

 

 

Edited April 3, 2023 by guy