Re: VMs: Oldest Dating

[Dennis <tsalagi@xxxxxxxx>]

elvogt@xxxxxxxxxxx wrote:
> 
> >       Gabriel notes on the EVMT page that carbon-14 dating
> > is very inexact for our putative time period, because
> > of the shape of the decay curve.
> 
> I guess you have to take it with a grain of salt. It's probably not as good as
> a Beinecke stamp "acquired 1435", but should still give you a result plus minus
> a few decades. IMHO.

	Apparently not.  On the EVMT website, 

http://web.bham.ac.uk/G.Landini/evmt/evmt.htm

I find:

(extracted from the Voynich mailing list, Dec. 1991)

    "Radiocarbon dating using an accelerator mass
spectrometer would be able to give you a date although
you would have to destroy approximately 30 mg of vellum
in the process. This would date the death of the animal
from which the skin was obtained to be made into
vellum. It would not give the time when the ink was
applied onto the vellum.  Obviously the ink could not
have been applied before the animal grew it's skin but
the ink could (theoretically) have been applied ANYTIME
afterwards. Unfortunately radiocarbon dating, being a
statistical technique, has a standard error term which
at one sigma is about +/-60 radiocarbon years. Because
there is not a linear relationship between radiocarbon
and calendar years it is necessary to calibrate the
radiocarbon age to obtain a calendrical one. The period
AD c.1600-1950 is a very bad one in radiocarbon terms
since production of 14C in the upper atmosphere kept
pace with radioactive decay so that there is a
"plateau". This means that it is not possible to
distinguish dates in the last few hundred years, only
to say that an object must date to sometime within that
period. [After 1950 the atomic bomb pulse makes
accurate dating possible]. It would be easy to check
whether the vellum dated to the 13th century AD or to
the period c.1600-1950 but it would not be possible to
check whether it belonged to 1600-1700 or to 1912. If
it is a forgery it is (just) possible that the forger
wrote on "old" vellum in which case the radiocarbon
date would tell you nothing about when it was written."

Dennis
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