Recycled Knowledge | by Brian Koberlein



23 October 2022

A folio from the Codex Climaci Rescriptus.
Peter Malik
A folio from the Codex Climaci Rescriptus.

In the event you suppose writing paper is pricey as of late, be glad you didn’t dwell within the center ages. Again then, paper was as uncommon as hen’s enamel, so good luck discovering some to jot down one. However if you happen to occurred to be a monk, chances are high there have been loads of previous books made from parchment. A lot of them have ineffective stuff like previous star catalogs, so why not simply recycle the parchment to your new copy of spiritual literature?

That is mainly how the Codex Climaci Rescriptus took place. Parchment is made out of animal pores and skin and processed into a skinny, paper-like materials. It’s laborious to make, however it may final for millennia underneath the appropriate situations. It will also be simply erased. Simply scrape the previous ink off with a pointy knife, and you might be good to go. This sort of recycling was often used all through the early center ages till paper manufacturing turned frequent within the 1500s. Consequently, we’ve a number of books just like the Codex Climaci Rescriptus with medieval texts overwritten on a lot older works. Now we have identified about this type of factor for greater than a century. In lots of circumstances, you may even see hints of the older underlying textual content, however good luck studying it. That has modified due to multispectral imaging.

How multispectral imaging reveals text.Museum of the Bible CC BY-SA 4.0
How multispectral imaging reveals textual content.

With multispectral imaging, you illuminate the textual content with totally different colours of sunshine and make high-resolution photographs of the parchment. Completely different inks and even the identical inks of various ages replicate mild in numerous methods. By combining photographs at totally different wavelengths, you may tease out the background textual content whereas minimizing the foreground textual content, thus making the previous textual content readable. In a latest examine, a group did this with the Codex Climaci Rescriptus, and located the unique writing contained fragments of the Hipparchus star catalog, which is regarded as the earliest detailed map of the northern night time sky.

Hipparchus was a Greek astronomer who compiled his catalog round 135 BCE. Sadly, his catalog was misplaced to the ages. We all know of it as a result of 4 centuries later Ptolemy mentions it within the textual content of his personal star catalog, Almagest, which we do have copies of. The Codex Climaci Rescriptus comprises the one direct fragments of the Hipparchus catalog we’ve. The group first discovered the fragments in 2017, however this new examine has revealed some attention-grabbing particulars, notably relating to the connection between the Hipparchus and Ptolemy catalogs.

One of many long-standing mysteries was whether or not Ptolemy copied the Hipparchus catalog wholesale and expanded it, or whether or not Ptolemy merely referenced Hipparchus whereas making his personal measurements. The group was capable of finding 4 constellations inside the Hipparchus fragments and found their star places are barely totally different from these within the Ptolemy catalog. Surprisingly, in addition they discovered that the Hipparchus constellations have been extra exact, with positions measured to the closest diploma. The accuracy of Hipparchus wasn’t equaled till the Persian astronomer Ulugh Beg compiled his Zij-i Sultani star catalog within the 1400s.

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