NavList:

I finally can report back on the markings found on the sextant used by Frank Worsley (owner Henry Hudson) aboard the James Caird, with Shackleton on the journey from Elephant Island to South Georgia Island.

I have written to and received replies from an extra ordinarily large group of individuals.  In fact, my quest could easily resemble the quest for the holy grail, with the exception that the grail would be easier to find.  I passed from one likely candidate to the next, each one passing me on.  I finally have spoken to the right person, who shall remain nameless, lest that person be inundated with silly requests.  The sextant is in a display case, but upon my request for information, the sextant was handled and photographed by this person.

On to the factual reporting
1) The serial number is L777.  If the letter A corresponds to 1901, then this sextant was manufactured in 1912.
2) The patent markings are identical to the markings on my sextant, to wit: the hezzanith endless tangent, the patent greatest angle clamp and the box release.
3)The inspection is by "Hezzanith Observatory Works" not Kew Observatory nor National Physical Laboratory.  It is dated Aug 1914.  It shows 0'-0" of arc error throughout.  The arc is silver and the telescopes are identical powers as well.
4) I am pleased to report that the inverting scope with cross hairs previously reported as missing, is indeed PRESENT.

DISCUSSION

The thing that jumps off the page is the Hezzanith Observatory Works certificate dated Aug 1914, compared to the 1912 manufacture date.  One can surmise that Henry Hudson, the sextants owner, wanted it re-calibrated just before the expedition set sail.  The expedition first set out to Buenos Aires on 8 Aug 1914.  Perhaps Hudson did not wish to wait in the queue at Kew for the re-calibration (pun fully intended).  There is nothing wrong with the certificate, its just that the testing was performed by the same firm that manufactured the certificate, not an independent house.  I've asked for permission to publish that certificate here as it is unusual.

The patent greatest angle clamp on the sextant was photographed.  It is of identical configuration and markings as I previously displayed related to my sextant.  No further evidence is to be found about why it is marked patent when no patent documentation can be found.  This remains a mystery.

I am thoroughly confused by the re-appearance of the inverting telescope with cross hairs.  This is a spectacular piece of optics.  In photographs of the US tour, the 'scope is missing.  In the photographs just received, it is present.  I cannot understand why it would be removed for the US tour.  Perhaps this is a replacement part?  I did find out that this sextant was loaned to another (modern) expedition.  Perhaps it was recovered from that expedition.  This too remains confusing.

The key is present!  This is usually the first item lost in my view, as it us not held with the sextant, rather with the original owner.

I have been cautioned not to publish the images of this sextant without permission.  I have already requested permission for that odd certificate.  If there is interest in other components, I can ask about that too.

Brad