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The sixteenth century Alderney crystal: a calcite as an efficient reference optical compass?
by Albert Le Floch, Guy Ropars, Jacques Lucas, Steve Wright, Trevor Davenport, Michael Corfield, and Michael Harrisson
Proceedings AVolume 469(2153):20120651
May 8, 2013
©2013 by The Royal Society
(a) The Alderney crystal (5×3×2.3 cm).
Albert Le Floch et al. Proc. R. Soc. A 2013;469:20120651
©2013 by The Royal Society
Case of an unpolarized light impinging on a calcite crystal.
Albert Le Floch et al. Proc. R. Soc. A 2013;469:20120651
©2013 by The Royal Society
Case of a linearly polarized light.
Albert Le Floch et al. Proc. R. Soc. A 2013;469:20120651
©2013 by The Royal Society
(a) Case of a partially polarized light.
Albert Le Floch et al. Proc. R. Soc. A 2013;469:20120651
©2013 by The Royal Society
Inductive coupled plasma-atomic emission spectroscopy (ICP-AES) spectra for the bulk of a freshly collected calcite crystal and of the Alderney crystal.
Albert Le Floch et al. Proc. R. Soc. A 2013;469:20120651
©2013 by The Royal Society
Mg2+–Ca2+ exchanges on calcite surface for a crystal partially immersed in a solution of MgNO3 in water.
Albert Le Floch et al. Proc. R. Soc. A 2013;469:20120651
©2013 by The Royal Society
Mg2+–Ca2+ exchanges on calcite surface for a crystal partially immersed in sea water.
Albert Le Floch et al. Proc. R. Soc. A 2013;469:20120651
©2013 by The Royal Society
Comparative roughness measurements obtained with a Taylor-Hobson surface profiler.
Albert Le Floch et al. Proc. R. Soc. A 2013;469:20120651
©2013 by The Royal Society
Typical perturbations of a magnetic compass by one of the excavated cannon of the Alderney ship.
Albert Le Floch et al. Proc. R. Soc. A 2013;469:20120651
©2013 by The Royal Society
Typical measured sky irradiances at twilight on 18 April 2011 at 48°07′ N, 1°41′ W. (a) The successive photographs are taken within 10 min intervals.
Albert Le Floch et al. Proc. R. Soc. A 2013;469:20120651
©2013 by The Royal Society
Typical bearing of the Sun at 22.16 during twilight for low irradiances.
Albert Le Floch et al. Proc. R. Soc. A 2013;469:20120651
©2013 by The Royal Society
Sun tracking experiment (see panel a).
Albert Le Floch et al. Proc. R. Soc. A 2013;469:20120651
©2013 by The Royal Society
Heating of a calcite crystal.
Albert Le Floch et al. Proc. R. Soc. A 2013;469:20120651
©2013 by The Royal Society