NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Bill Morris
Date: 2015 Sep 26, 21:07 -0700
A few sextants did have platinum arcs and were often labelled "platina". When first isolated in a reasonably workable state in about 1805 or thereabouts it was cheaper than silver, as no one could think of a use for it It soon became very expensive and applied only to high end sextants as other uses were found for the metal. It would not surprise me if some of them were scrapped for the platinum. A friend told me of a visit to a second-hand dealer who said he had bought a job lot of war surplus sextants in England after WW II. The dealer said he had scrapped them for the silver.
The ultimate in luxury was a golden arc inlaid into a silver limb. A kind person gave me such an instrument. You can see it here: http://sextantbook.com/2014/01/ . If anyone wishes to give me one with a platinum arc, I will cherish it just as much.
Bill Morris
Pukenui
New Zealand