Using Chemistry to Uncover a History: Is this an early map of North America - or not?

c. Michelle M. Francl, 2004

Full module available as PDF from the author at mfrancl@brynmawr.edu

keywords: spectroscopy • analytical chemistry • archeology

Primary Literature Reference: This module is based on Anal. Chem. 2002, 74, 3658-3661. "Analysis of Pigmentary Materials on the Vinland Map and Tartar Relation by Raman Microprobe Spectroscopy " by Katherine L. Brown and Robin J.H. Clark.

Background:

Just before Columbus Day in 1965, Yale University unveiled a spectacular item in its collection of rare manuscripts: a map of North America dated before Columbus. The Vinland Map appeared to be the record of a journey by Leif Eriksson to the New World and was reportedly insured for more than $25 million. Interestingly, the mapÕs provenance was thin. It appeared to have been discovered in the leaves of another manuscript in the early 20th century, leaving its whereabouts for the previous 500 years unknown. Paleographers often view documents without a strong provenance as forgeries until proven otherwise, and the Vinland map was no exception. Some scholars were suspicious of oddities in the Latin such as rendering Eriksson as Ericsonnius instead of Erici filius, others point to matching worm holes in the map and the documents inside which reportedly it had been found.

Lacking definitive historical evidence, chemists entered the fray. In the 1970s examination of the map revealed the presence of anatase, a pigment unknown in the period during which the map was supposed to have been produced. Yet subsequent radiocarbon dating of the parchment indicated that it, at least, was of the appropriate age. Further studies of the inks and pigments on the Vinland map and the Tartar Relation (another document found with it) lent credence to the theory that the map is a hoax. The scholarly exchange is getting heated, witness the beginning of a letter from Prof. Robin Clark to the editor of the journal Analytical Chemistry: "Unfortunately [Olin's] article is based on speculation, lacks logic, and lacks either new information or new insight on the ink, consisting merely of a rewriting of her earlier publications. Its publication has provided the scientific and popular press with fuel with which to fire further, entirely unjustified, controversy on this subject."

Sample Critical Reading Questions:

• The radiocarbon dating experiments referred to by the authors have now been published, why are they not definitive? What is the advantage of the Raman spectroscopy relative to radiocarbon techniques?

Sample Problem:

• The use of vermilion on rubric of the Tartar Relation is confirmed by the presence of three lines attributed to HgS. Why should this diatomic have more than one vibrational line?

Culture of Chemistry Feature:

Medieval Ink Recipes