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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Ivory scales
From: Alexandre Eremenko
Date: 2007 Jan 07, 16:15 -0800
From: Alexandre Eremenko
Date: 2007 Jan 07, 16:15 -0800
Why the scales of octants and some sextants were made of ivory? Does ivory have some favorable heat expansion properties? Or any other good physical properties? Or what? If I understand correctly that "ivory" is the substance made of an elefant's tusk, it seems to be that even in 1820-s ivory was not cheaper than silver. I could not figure the price, but only found that 3,000 cwt (=hindredweight=100 pounds) of ivory was sold in 1827 in London. I'd guess that silver was cheaper. On the other hands ivory was used on cheap octants and silver (or gold or platina) on expensive sextants. (Nowadays it is reversed, of course: cheap American ebony-ivory-brass octants are sold on e-bay for higher price than fancy British sextants:-) Alex. --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---
