>A bit off the refraction topic but Chuck O'Connell expressed interest in
>dials that use polarisation. There was an interesting article recently in
>one of the BSS Bulletins about using Sellotape as a polarising medium to
>make a dial that would indicate hours even when it's cloudy - it uses the
>fact that the background light from the sky is polarised.
The article was in the BSS Bulletin 98.1 February 98 pages 3-9. The 'dial'
is based on Charles Wheatstone's use last century of the polarisation of
skylight to determine the azimuth of the sun.
Les Cowley
Halos on the web
http://dspace.dial.pipex.com/lc/halo/halosim.htm
