Editing Vinland Map (section)

=== Analysis of ink ===
[[File:beinecke-speculum-hist-223r-det.jpg|right|thumb|The last remnant of old ownership marks in ''Speculum historiale'']]
Complaints were made at the Conference that no scientist had been permitted to examine the map and its companion documents in all the years of study since 1957. Skelton's scientific colleagues at the British Museum made a short preliminary examination in 1967 and found that:

{{ordered list|list_style_type=lower-alpha|
| despite its appearance to the naked eye, the ink was certainly not conventional [[iron gall ink|iron-gall ink]] like its two companion manuscripts, and indeed was unlike any recipe they had ever seen (they spent several months after the initial testing trying to find similar inks as far afield as Iceland);
| the map outline appeared to consist of two superimposed lines, one black (but mostly vanished) which looked like graphite or soot, and one yellowish;
| the whole of the map [[parchment]] (again, unlike its companions) had been coated or soaked in an unknown substance—they were not allowed to take a large enough sample to analyze it;
| they could not be certain that the two halves of the map, held together by a binding strip glued on the back, had ever been a single sheet—unlike any other known medieval double-page map; looking at the map, it is clear that the artist knew exactly, to the nearest millimeter, where it was going to be folded, because several place-names start or finish right next to it while none are written straight across it, and the rivers of eastern Europe run parallel to it;
| the rebinding of the ''Speculum'' volume without the map and ''Relation'' had used plastic thread, only available since about 1950.<ref>{{cite journal
  | author= A.D. Baynes-Cope
  | title= The Scientific Examination of the Vinland Map at the Research Laboratory of the British Museum
  | journal= Geographical Journal
  | volume= 140
  | pages= 208–211
  | year= 1974  | doi = 10.2307/1797077
  | issue= 2
  | jstor= 1797077
 | bibcode= 1974GeogJ.140..208B
 }}</ref>}}
 
In 1972, with new technology becoming available, Yale sent the map for chemical analysis by forensic specialist [[Walter McCrone]] whose team, using a variety of techniques, found that the yellowish lines contain [[anatase]] (titanium dioxide) in a rounded crystalline form manufactured for use in pale pigments since the 1920s, indicating that the ink was modern. They also confirmed that the ink contained only trace amounts of iron, and that the black line remnants were on top of the yellow, indicating that they were not the remains of a penciled guide-line, as the British Museum staff had speculated.<ref name="mcr1">
{{cite journal
 |author1=Walter C. McCrone  |author2=Lucy B. McCrone
  |name-list-style=amp | title= The Vinland Map Ink
 | journal= Geographical Journal
 | volume= 140
 | pages= 212–214
 | year= 1974
 | doi= 10.2307/1797078
 | issue= 2
 | jstor= 1797078 |bibcode=1974GeogJ.140..212M
 }}</ref>

A new investigation in the early 1980s, by a team under Thomas Cahill at the [[University of California, Davis]], using [[particle-induced X-ray emission]] (PIXE) found that only trace amounts (<
&nbsp;0.0062% by weight) of titanium appeared to be present in the ink,<ref name=cahill85>
{{cite book | last = Cahill | first = Thomas A.| title = Further Analysis of the Vinland Map, Tartar Relation, and Speculum Historiale | publisher = Crocker Nuclear Laboratory | date = 1985}}</ref> which should have been too little for some of McCrone's analyses to detect.<ref name=towe90>
{{cite journal | author= K. M. Towe | title= The Vinland Map: Still a Forgery | journal= Accounts of Chemical Research | volume= 23 | issue= 3 | pages=84–87 | year= 1990 | doi =10.1021/ar00171a005 | url=http://www.webexhibits.org/vinland/paper-towe90.html | format= Reprint | access-date=2007-10-26 }}</ref> The Cahill team acknowledged, however, that titanium was the only element within their technique's measurement capability which was significantly more concentrated in the ink than on the bare parchment (other elements such as iron and zinc were found concentrated in some inked samples, but only a minority). One member of the team, Gregory Möller, also analyzed loose particles retrieved from the split down the middle of the map by a different method, finding that most of them were rich in titanium (though a few black particles were rich in chromium and iron).<ref>Gregory Möller, "Preliminary Report on the Scanning Electron Microscope Analysis of Particles from the Vinland Map", unpublished</ref> Because they were the first to apply PIXE to ink analysis, nobody at the time could explain the difference between the Cahill and McCrone figures. Attempting to reconcile the conflicting results, the Cahill team suggested that the high concentrations found by McCrone were due to a combination of contamination from modern dust, and poor sample selection (i.e. choosing contaminant particles like those in the split);<ref>Skelton et al. (1995) pages xxix-xxxix</ref> however, they also chose not to publish or publicise Möller's loose particle study.<ref>
{{cite journal | author= T.A. Cahill | author2= R.N. Schwab | author3= B.H. Kusko | author4= R.A. Eldred | author5= G. Moller | author6= D. Dutschke | author7= D. L. Wick | author8= A.S. Pooley | title= The Vinland Map, Revisited: New Compositional Evidence on Its Inks and Parchment | journal = Analytical Chemistry | volume= 59 | pages= 829–833 | year= 1987 | doi= 10.1021/ac00133a009 | issue= 6 }}</ref> The accumulation of large amounts of PIXE data from other laboratories around the world in the ensuing decades was sufficient by 2008 to show that the Cahill figures for all elements in the inks of the map and its companion documents are at least a thousand times too small,<ref name=cahillsample>
{{cite web | last = Cahill | first = Thomas A.| title = Excerpts from Appendices to: Further Analysis of the Vinland Map, Tartar Relation, and Speculum Historiale | publisher = collage by PastPresented, 2015 | date = 1985 | url =http://www.pastpresented.ukart.com/Vinland-Map-PIXE-b.gif | access-date =2015-01-31}}
</ref> so the discrepancy is due to a problem with their work.<ref name=towe08>{{cite journal |author1=K. M. Towe |author2=R. J. H. Clark |author3=K. A. Seaver | title= Analysing the Vinland Map: A Critical Review of a Critical Review | journal= Archaeometry | volume= 50 | pages= 887–893 | year= 2008 | doi = 10.1111/j.1475-4754.2008.00428.x | issue= 5 |url=http://si-pddr.si.edu/dspace/bitstream/10088/6565/1/Towe_Seaver_Archaeometry_2008.pdf|citeseerx=10.1.1.482.5712 }}</ref>

[[Image:Vinland-map greenland.jpg|thumb|right|Greenland from the Vinland Map superimposed (in green) on an early-20th-century atlas map. The [[Wikt:stipple|unstippled]] area at the northern tip represents land not surveyed until after 1896.]]

The McCrone team had also made mistakes, though none as fundamental as Cahill's. Revisiting his notes in 1987 to draft a detailed reply to the abbreviated public version of Cahill's report, Walter McCrone chose the wrong sample to illustrate a "typical" black ink particle, selecting one which had been found only loosely attached to the ink.<ref>{{cite journal | author= Walter C. McCrone | title= The Vinland Map | journal = Analytical Chemistry | volume= 60 | pages= 1009–1018 | year= 1988 | doi= 10.1021/ac00161a013 | issue= 10 }}</ref> By focusing on this contamination, rich in chromium and iron, he gave Cahill the opportunity to re-emphasise his case in an essay for an expanded version of the 1965 official book, a few years later.

In 1991, McCrone, then director and senior research microscopist with the [[McCrone Research Institute]], visited Yale to take new microsamples from the map, partly to check his earlier results, and partly to apply new techniques. Photomicrographs taken at 1 [[micrometer (unit)|micrometer]] intervals through the thickness of ink samples demonstrated that the manufactured [[anatase]] particles were not just sticking to the surface as Cahill's criticisms had implied, and [[Fourier transform spectroscopy]] identified the ink's binder as gelatin, probably made from animal skin.<ref>
{{cite journal | author= Walter C. McCrone | title= Vinland Map 1999 | journal= Microscope | volume= 47 | pages= 71–74 | year= 1999 | url=http://www.mccroneinstitute.org/uploads/vinland_map_1999-1422459928.pdf| issue=2}}</ref> In July 2002, using [[Raman spectroscopy]], the presence of significant quantities of anatase in the map ink was confirmed by British researchers Katherine Brown and Robin Clark, and the remaining traces of black pigment in the ink were found to consist essentially of soot-type carbon.<ref name=brownclark>
{{cite journal |author1=Katherine L. Brown |author2=Robin J. H. Clark | title= Analysis of Pigmentary Materials on the Vinland Map and Tartar Relation by Raman Microprobe Spectroscopy | journal = Analytical Chemistry | volume= 74 | pages= 3658–3661 | year= 2002 | doi = 10.1021/ac025610r | url=http://webexhibits.org/vinland/paper-clark02.html? | format= Reprint | access-date=2007-10-26 | issue= 15 |pmid=12175150 }}</ref>

Various scientists have formed their own theories to explain how the 20th century manufactured anatase in the Vinland Map ink could have got into genuine medieval ink. The first was chemist Jacqueline Olin, then a researcher with the Smithsonian Institution, who in the 1970s conducted experiments which produced anatase at an early stage of a medieval iron-gall ink production process. Examination of her anatase by a colleague, mineralogist Kenneth Towe, showed that it was very different from the neat, rounded crystals found in the Vinland Map and modern pigments.<ref name="towe90"/><ref>
{{cite journal
 | author= Jacqueline S. Olin
 | title= Evidence That the Vinland Map Is Medieval
 | journal = [[Analytical Chemistry (journal)|Analytical Chemistry]]
 | volume= 75
 | pages= 6745–6747
 | year= 2003
 | doi = 10.1021/ac034533c
 | url=http://webexhibits.org/vinland/paper-olin03.html?
 | format= Reprint
 | access-date=2007-10-26
 | issue= 23
 | pmid= 16468159
 | doi-access= free
 }}</ref><ref>
{{cite journal
 | author= Kenneth M. Towe
 | title= The Vinland Map Ink Is NOT Medieval
 | journal = [[Analytical Chemistry (journal)|Analytical Chemistry]]
 | year= 2004
 | volume= 76
 | pages= 863–865
 | url= http://webexhibits.org/vinland/paper-towe04.html?
 | format= Reprint
 | access-date=2007-10-26
 | doi=10.1021/AC0354488
 | pmid= 14750887
 | issue= 3
 }}</ref> Towe himself, a clay specialist, briefly considered the possibility that the anatase could have come from clay, where it is present in trace amounts, but on checking McCrone's data found no significant traces of clay minerals. Shortly before the Raman analysis was published, historian Douglas McNaughton based a mistaken theory about the ink around McCrone's emphasis on the chromium-rich black particle, having obtained unpublished data on the similar particles in Möller's report.<ref>{{Cite book
  | last = McNaughton
  | first = Douglas
  | contribution = Scientific Studies of the Vinland Map
  | title = Vikings: The North Atlantic Saga
  | pages = 269
  | publisher = Smithsonian Books
  | place = Washington, D.C.
  | year = 2000}}</ref>
 
Olin published a paper that identifies the anatase in the Vinland Map ink as being truncated bi-pyramidal rather than rounded crystals <ref>{{cite journal |last=Olin |first=J.S. |year=2013 |title=The Vinland Map: Transmission Electron Micrograph of the Ink |journal=International Journal of Advances in Chemistry |volume=1 |number=1 }}</ref> (however, this is not vastly different from the McCrones' 1974 description of the crystals as "smooth, rounded rhomb shapes"<ref name="mcr1"/>).