In the middle of the Middle Ages, the library of the Bobbio abbey had books dealing with all branches of knowledge, both human and divine. There were more than 600 volumes that turned this place founded by Saint Columban in the year 614 into one of the most important collections of manuscripts in Italy at that time.
Its white stone buildings, its dark passageways and its bucolic mountain setting inspired the writer Umberto Eco for his famous book The Name of the Rose, that crime novel riddled with murders and rites that was adapted to the cinema by Jean-Jacques Annaud and featured Sean Connery and Christian Slater as leads.
A palimpsest (a manuscript made from a previously used parchment) came out of Bobbio some time ago and is currently kept in the Biblioteca Ambrosiana in Milan. That document contained a Latin text of Isidore of Seville's Etymologies. But underneath there was something else.
Researchers from the Sorbonne University and New York University have discovered that the parchment sheets were erased in the 8th century for reuse. In the process, however, an important astronomical treatise written by Claudius Ptolemy in the second century BC was destroyed.
The original content, believed to be lost, was unmasked using multispectral imaging that has allowed Victor Gysembergh, Emmanuel Zingg and Alexander Jones to decipher and interpret the document, which contains the oldest known description of a scientific instrument called a Meteoroscope, as explained in a article published in the Archive for History of Exact Sciences.
This tool allowed mathematicians to calculate heights and distances. Ptolemy invented it specifically to "better specify the sites of the places and to know the distances that they had from one another and to which side they were located, if to the North or to the East or what they were deviated by some other particular respect or inclination" , according to Alonso de Santa Cruz in his Libro de las longitudes (1567).
"(The text is) at the intersection of the natural sciences and the humanities and is composed, in particular, of 15 sheets of a Greek manuscript from the 6th or 7th century BC that were later used to store various works," they explain. the researchers.
There were three Greek scientific texts: one of unknown authorship on mathematical and catoptric mechanics, 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 unknown. read (six sheets).
To obtain the multispectral images, the experts first had the help of the French company Lumière Technology and, later, with an international team made up of EMEL (Early Manuscripts Electronic Library), Lazarus Project, Rochester Institute of Technology and the company MegaVision Inc. .
“The document, which has gaps, describes the construction and use of a nine-ringed armillary sphere, identifiable as the Meteoroscope. This important discovery sheds new light on the history of ancient astronomy 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."
