3/10/21 Report - Recent Treasure Coast Find of A Historic Navigational Instrument. Beaches Mostly Filling.

 Written by the TreasureGuide for the exclusive use of the Treasure Beaches Report.

Recent Finds by JD To Be Identified.

Yesterday I posted some recent finds by JD that included the parts shown above.  Everybody seems to agree that they are the parts of a navigation instrument.  I do not think it can be determined whether the instrument is an quintant, octant or sextant because the frame, which was likely made of wood, is no longer present.  Nonetheless the parts have been identified.

Here is an image that conveniently shows parts similar to those that were recently found.  I added the labeled arrows.

Octant Illustration Showing Parts
Like Those Recently Found by JD.
Source: http://www.etesseract.com/Navigation/Navigation.html

Shown above is an image of an early American or English octant, circa 1750 - 1760.  It is described as "one of the earliest surviving octants."  The date is significantlhy later than 1715. 

Many sources give dates later than 1715 for the invention of the sextant - but not all.  It seems to me that the sextant is a development on the octant and would therefore on average be of a slightly later date, but the octant was used long after the invention of the sextant.  Correct me if I'm wrong about any of that.

Here is perhaps a more precise statement.

In ancient times the term quadrant was used for an instrument to determine the altitude of the stars on top of the horizon. A quadrant was a division of the Nautical Rose or Winds Rose.

The sextant was used since 16^th century, but the marine version was developed in 1757 by Captain John Campbell. The name sextant refers to a sixth of a circumference, that is 60°. Therefore the sextant can measure angles to 120°. The octant operates in a similar way but measures smaller angles.

That was found on the following web site which discusses an octant found on the wreck of the Spanish ship Salvador, which sank on August 31, 1812 in the Maldonado Bay.

The instruments were recovered on 9 meters depth, covered with sediments. An octant was built over an ebony wood frame to 3.80 cm in height and 33 cm in width. It has bronze pieces and an ivory scale. One has the engraving “Spencer, Pronning & Rust, London“ and on the other octant it reads “James & Wilson (B&R)”.

Here is the link, which you might enjoy.  Spanish troopship Salvador (abc.se)

A few question remain.   Since so much of what is found in that area of the Treasure Coast seems to be from the nearby 1715 Spanish wreck, it is easy to assume the finds are from the wreck.  But you will recall that there is also a salvage camp in the area and a later English salvage camp, which has produced English military buttons and artifacts from a later date.  It would be nice if some marks were found on the parts that could help narrow down the date and source of the instrument. 

Congratulations to JD on a great find.   

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See also Octant (instrument) - Wikipedia

Of course octants and sextants etc. vary in numerous details.  You'll see some examples with rounded holders for the lenses and mirrors, and others will have square frames, for example.  

Here is another illustration that you might find interesting.  The parts are very similar to those recently found.

 

Thanks to all of  you who provided input.

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Fort Pierce South Jetty Beach Tuesday.

I did a little detecting Tuesday.  Found a lot of modern coins and some other things I need to get cleaned. The beaches I saw were deteriorating.

John Brooks Beach Tuesday.

At John Brooks some filling had taken place.  The cut was not as high and the slope was mushy.

John Brooks Beach Tuesday.

It looks like we'll have around a four-foot surf for a few days, and then the wind will become more southerly and the surf will decrease.

Anyone have any thoughts on the pendant I posted yesterday?

Happy hunting,

TreasureGuide@comcast.net