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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: micrometer sextants.
From: Wolfgang K�berer
Date: 2007 Nov 8, 21:05 +0100
From: Wolfgang K�berer
Date: 2007 Nov 8, 21:05 +0100
Frank, I don't believe it was a matter of the English manufacturers shunning patent royalties; it is more likely that micrometer sextants were generally considered to be less accurate than vernier sextants. The 1930 article that George sent states this very clearly and in fact announces that Heath has overcome the problems leading to inaccuracies (backlash, "pull" on the sextant centre etc.). Even in the Plath patent description of 1921 the vernier is described as being more accurate, it says that the micrometer has been added to be able to get a quick reading when no high accuracy is required. Wolfgang -----Urspr�ngliche Nachricht----- Von: NavList@fer3.com [mailto:NavList@fer3.com]Im Auftrag von frankreed@HistoricalAtlas.net Gesendet: Montag, 5. November 2007 03:34 An: NavList@fer3.com Betreff: [NavList 3780] Re: micrometer sextants. Of the 1930 Brown's Nautical Almanac, I wrote: "One ad shows a high-end vernier sextant that has a micrometer drum, too." And Wolfgang added: "That was patented by C.Plath in 1921." So then perhaps the delay in English sextants was simply because no English manufacturer was willing to pay patent royalties until they knew there was strong market demand for micrometer sextants (??). And about Plath, do you know: did they begin manufacturing such sextants in 1921? Or was that the patent date only? -FER http://www.HistoricalAtlas.com/lunars --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---