NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Brad Morris
Date: 2014 Jan 21, 17:02 -0500
Kinch
Thanks for that. The illustration shows the clamp stamped with "patent greatest angle clamp". That implies that (1) there *is* an earlier patent than 1921 and (2) the sought after patent proceeds 1900.
BTW, does anyone have or have seen that artificial horizon telescope? That's sweet!
Brad
Brad….thought you might appreciate knowing that the clamp has been around since at least 1900. (see attached).
Kinch.
From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of Brad Morris
Sent: 20 January 2014 18:43
To: BrenKinch---.com
Subject: [NavList] Re: Beating a Dead Horse (aka Worley's Sextant)
Don
Of course, since my device does say 'patent' it implies that there is an earlier version by the same patentees, on the same topic. You've got the later one, but its the earlier one we seek!
Brad
On Jan 20, 2014 11:52 AM, "Brad Morris" <bradley.r.morris---.com> wrote:
Thanks Don, for explaining away those conundrums!
On Jan 20, 2014 10:47 AM, "Don Seltzer" <timoneer---.com> wrote:
Brad,
I think I can explain away your date conundrum. The 1921 patent application states that it is an improvement over the previously used 'greatest angle clamps'. Figures 1 and 2 show the previous design, and Figures 3 and 4 show the improved clamp being claimed. All of your attached photos clearly show the previous model, not the 1921 improvement.
Don Seltzer
-------
Hi Don
Yes! That's it. No doubt about it.
Unfortunately, it brings up a few issues, one major.
1). My inspection certificate is dated January 1921. The patent date is November 1921. This little conundrum is not nearly as significant as the next.
2) Shackleton's Trans Antarctic Expedition began in earnest (pun fully intended) in 1914. How could "the" sextant used by Worsley have this feature? And yet there it is!
In the attached photos (for the benefit of Frank, I've stopped now to include them) you can see it the patent greatest angle clamp hanging in the box, mounted on the arc, and by itself on the lid of the box.
Compare to the image from the James Caird Society, showing at a patent greatest angle clamp, pre patent date. http://fer3.com/arc/m2.aspx/Fw-Image-Sextant-Used-Worsley-Huxtable-mar-2009-g7574. Its there, unfortunately without enough resolution to see just how much of a match it is. There's just enough detail in the tourist photo I found in 2009 to show that the general construction is the same.
Brad
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Attached File: 
(f1-GB184728A.pdf: Open and save or View online)
Attached File: 
(img/126607.greatest angle clamp.pdf: Open and
save or View
online)
