Researchers suspect that Vikings used this effect in combination with a 'sunstone' (Icelandic Spar) to navigate by the sun even when it was hidden by clouds. A

Researchers suspect that Vikings used this effect in combination with a 'sunstone' (Icelandic Spar) to navigate by the sun even when it was hidden by clouds. Article: http://news.discovery.com/earth/navigating-by-sunstone-and-a-sixth-sense.htm http://news.discovery.com/earth/navigating-by-sunstone-and-a... Paper: http://rspa.royalsocietypublishing.org/content/468/2139/671 http://rspa.royalsocietypublishing.org/content/468/2139/671