Assumptions baked into the VMS carbon dating

[Jorge_Stolfi]

Lisa told us that there is no difference in parchment quality between sections. It's all equally bad.

To the extent one can see from the scanned images, that seems to be true.  But it does not mean that all sheet are equally bad.  Wasn't there a testimonial that the folios varied in thickness and finish?

From the images, the Herbal folios seem to be generally uniform, but there are many exceptions:

• f5, f13, f26, f37, f38, and others have a slanted free edge.
  
• f9 and others have a tear that was sewn closed during manufacture.
  
• f10, f13, f14, f129, and many others seems to be 1 cm narrower than most.
  
• f15, f36, and others seem to be 2 cm narrower than most.
  
• f14, f30, and others have big holes or skin edges at the free edge.
  
• f28, f34 and others have holes from the original skin.
  
• f29, f50, f55, and others have conspicuous creases.
  
• f66 has half of a big hole along the bottom edge
  

Similar defects are seen in the Bio and Starred Parags sections.  In the latter,

• f105+f114 and f104+f115 have a slanted bottom edge, 1-2 cm too short at one end.
  
• f112 has a surface finish defect at the top right that makes it unwritable.
  

But at least all the bifolios in those sections have very roughly the same dimensions.  Whereas the fold-out bifolios (that include f67+f68) have "non-standard" width, and often end with a flap with irregular free edge that is only a fraction of the width of a normal folio.  And of course the Rosettes bifolio has a very dfferent size and shape too.

Those defective folios look like off-cuts or rejects, that a merchant could have sold at a discounted price, or that some professional scribe or scriptorium could have donated to the Author. Why should we assume that they all came from the same manufacturer and were all made within a range of a few years?

How realistic is it that the author(s) acquired bad parchment, and similarly bad parchment decades later?

If his means were scarce when he started creating the VMS, why would his financial condition improve over the course of the next 30 years?

But, again, even if he acquired all that third-grade vellum in the span of a few months, it does not follow that it was all made in the span of a few years.

If we accept Taccola as a source, this would place the lowest boundary for at least the Balneo and Cosmo sections to the 1420s. More realistically the 1430s. The older 1308-1362 peak implies that the parchment [of that section] would have been at least 60 years old when used, even up to 125 years.

  

No objections to that for the Balneo section.  But is there any plausible Taccola influence on Astro/Cosmo, which contains f68? 

Anyway, given that the vellum of f68 looks like an off-cut, it would not be unlikely that it was left in a "rejects" box in the corner of a scriptorium or someone's attic for a century or more.  Vellum is not perishable and does not change appreciably in that time scale.

All the best, --stolfi