Iceland Spar

[Monte Davis]

That first paragraph is a little overheated: what is actually new, I think,
is the first discovery of Iceland spar (1) *in a navigational context*
("next to a pair of dividers" on a sunken ship), and (2) in connection with
Tudor English sailors, even after magnetic compasses came in. Both of which
are indeed cool.

 

But Newton and Huyghens were studying calcite's double refraction in the
17th century; Arago showed in 1809 that sunlight is polarized, allowing the
sun's location to be narrowed down through overcast or over the horizon; and
in 1967 "Danish archaeologist Thorkild Ramskou posited that the [Viking]
sunstone could have been one of the minerals (cordierite
<http://en.wikipedia.org/wiki/Cordierite>  or Iceland spar
<http://en.wikipedia.org/wiki/Iceland_spar> ) that polarize
<http://en.wikipedia.org/wiki/Polarizer>  light and by which the azimuth
<http://en.wikipedia.org/wiki/Azimuth>  of the sun can be determined."
(http://en.wikipedia.org/wiki/Sunstone_%28medieval%29) That's been widely
cited since by historians. So this is more of an incremental,
all-but-clinching step than a sudden emergence from a cloud of medieval woo.


 

From: owner-pynchon-l at waste.org [mailto:owner-pynchon-l at waste.org] On Behalf
Of James Kyllo
Sent: Wednesday, March 06, 2013 2:00 PM
To: p-list
Subject: Iceland Spar

 

 

"...the French-led team have concluded that shards of Icelandic spar can act
as a remarkably precise navigational aid..."




http://www.independent.co.uk/news/science/archaeology/not-just-the-stuff-of-
legend-famed-viking-sunstone-did-exist-believe-scientists-8521522.html

 

Fascinating stuff

 

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