Sunday, January 7, 2018

The Mystery of the RO Numbers

In my research on the origins of the Nikumaroro sextant box, I’ve come across dozens of sextants that were made for the U.S. Navy and inspected at the U.S. Naval Observatory in the early decades of the 20th century.  These sextants can be recognized by the Naval Observatory serial numbers scratched into their limbs.  The Naval Observatory serial numbers I’ve seen on these sextants are four digits long or less and are invariably preceded by the Naval Observatory 'NO' hallmark, i.e., the letter ‘N’ inscribed in the letter ‘O’.  All the sextants marked in this way were made by American manufacturers, and while most of them were made by Brandis and Sons, I’ve also seen sextants made by three other companies, Keuffel & Esser, Buff & Buff, and Stackpole & Brother, and a very old sextant box that originally held a Warner & Swasey sextant [1].  The boxes for many of these sextants contain a certificate prepared by the U.S. Naval Observatory providing corrections to apply for small angular measurement biases specific to each sextant.

A Typical Naval Obsevatory 'NO' Marking

A Naval Observatory Inspection Certificate

Five sextants that I’ve seen have markings that indicate that they were once in the U.S. Navy’s possession and that they were inspected at the Naval Observatory, but they are distinctly different from the sextants I’ve just described.  One sextant's frame has a bell-like outline, within which there are three circular rings abutting arranged in a triangular pattern.  Neatly inscribed in its limb is ‘Cairns, 12 Waterloo Road, Liverpool’; ‘Cairns’ apparently refers to Alexander Cairns, a instrument dealer in Liverpool, England, during the third quarter of the 19th century [2].  Scratched into the limb is ‘US Navy’ followed by an ‘R’ inscribed in an ‘O’ and then the number 11317.

Cairns Sextant Limb Markings

Another sextant is in the New Bedford Whaling Museum’s collection, donated by the family of a late 19th century New Bedford whaling captain named Daniel W. Gifford.  A museum catalog indicates that the limb is marked ‘Spenser, Browning & Co London’, ‘US Navy’, and the ‘RO’ symbol followed by the number 16977 [3].  Spenser, Browning & Company was a navigational instrument maker in London, England, in the middle decades of the 19th century [4].

The Captain Gifford Sextant

A third sextant, also made by Spenser, Browning & Co., appeared in the online catalog of an antiques dealer [5].  The inside of the sextant’s box lid is marked ‘Paris Exhibition 1867, George Davidson, U.S. Coast and Geodetic Survey Philadelphia, Pa’.  It has a 10-inch radius frame, and the catalog listing indicates that it is marked “U.S. Navy 30183”.  A close-up view of the limb in a catalog photo is not sharp, but I can see that the number 30183 is preceded by the Naval Observatory ‘NO’ hallmark and followed by an ‘RO’ symbol.

George Davidson U.S. C&G.S. Sextant

A fourth sextant, which is currently listed as for sale in the online catalog of another antiques dealer [6], has 'Captain Walton O. Hooker Jr Gardiner Maine Ship “Harry Morse" 1878' marked in script on its index arm and on a plate on the the sextant’s box.  The catalog listing indicates that the limb is marked 'E. Loueux a Paris (2266)  Schiaveni Bellieni a Bresl', and 'US Navy R31518'; a close-up view of the limb reveals the latter marking to be US Navy followed by an ‘RO’ symbol and the number 31518.  Attached to the inside of this sextant’s box lid is a U.S. Navy inspection certificate dated October 10, 1918, indicating that it was classified as a high grade sextant.  I have found nothing confirming that a sextant maker or dealer of by name Loueux existed, and so I’ve wondered if this sextant was actually made by Lorieux, a French instrument maker in the 19th century.

Captain Hooker Sextant and Box

Box Handle Anchor Plate, Captain Hooker Sextant

Limb Markings on the Captain Hooker Sextant

The fifth sextant is an octant with an eight-inch radius brass frame with an ivory arc scale that was listed in an online auction held in 2010 [7].  The octant is described as being marked ‘US Navy 13126’, and the box that holds it is said to contain a label for D. Eggert & Son, a marine chronometer maker and seller of nautical instruments in 19th century New York City [8].  From what little I know of D. Eggert & Son, they were not sextant makers, thus it is unclear who this sextant’s manufacturer was. The auction listing does not mention an ‘RO’ symbol, but I think it likely based on the examples of the four previous sextants that an ‘RO’ symbol  precedes the ‘13126’.

D. Eggert & Son Sextant

I didn’t doubt that the markings scratched into the limbs of these five sextant were put there by the U.S. Naval Observatory, but why were they different than the usual Naval Observatory markings?  What was the ‘RO’ symbol in place of the usual Naval Observatory hallmark meant to signify, and why were the serial numbers following the ‘RO’ symbol five digits long, not four digits or less?

The five sextants were not only different in terms of how the Naval Observatory marked them, they were very different kinds of sextants than the ones the U.S. Navy typically acquired in the early 20th century.  At least four of the five sextants were made by non- U.S. sextant makers, and the frame radius and bracing pattern of several of them don’t conform with the U.S. Navy sextant specifications.  All five sextants appear to have been made in the 19th century and so they are older than any of the sextants whose limbs are marked with NO serial numbers.  Several of them appear to have been in the possession of private citizens (the Captain Gifford and Captain Hooker sextants) or a civilian government entity (the George Davidson Coast & Geodetic Survey sextant).  Many sextants with the usual ‘NO’ number markings ended up in the hands of private citizens or civilian organizations after they left U.S. Navy service, but it seemed quite possible that these three sextants were used by civilians before they entered U.S. Navy service.  So, my guess was that the OR serial number system was used by the U.S. Navy to track non-standard sextants that it had acquired in some way other than its usual acquisition process, which I understand to have been to purchase sextants made to U.S. Navy specifications from the manufacturer that offered them at the best price through a competitive bidding process [9].

At first I had no idea how or why the Navy might have come to possess these five sextants, but then I remembered something I had read about in the Annual Reports of the U.S. Naval Observatory.  When the United States entered into the First World War, U.S. manufacturers were unable to meet the demand for many kinds of nautical instruments needed by the Navy and merchant marine fleet.  U.S. Navy Assistant Secretary Franklin Delano Roosevelt therefore led a campaign to solicit the public for donations of nautical equipment [10].  The campaign was publicized with Eyes for the Navy posters like the one below, which emphasized the need for binoculars and spyglasses to help the crews of naval vessels and merchant ships look for German submarines.

Eyes For the Navy Poster

Binoculars and spyglasses were not the only kinds of equipment the Navy asked the public to donate, however.  An organization called The Four Minute Men, which sent speakers into theaters throughout the country to give short speeches urging the public to donate nautical equipment to the Navy.  An internal memo circulated by the organization to help its members prepare their speeches contains a statement from the Navy about what equipment was needed and how donated items would be handled [11]:

"Send your binoculars, spyglasses, and telescopes by parcel post or express to Franklin D. Roosevelt, Assistant Secretary of the Navy, care of Naval Observatory, Washington, D. C. (Sextants and chronometers are also urgently needed). On the outside of the package write your name and address. On the inside, tie a tag on the instrument, again giving your name and address.
Immediately upon receipt you will get a letter from the Naval Observatory, stating that a test will be made.

Instruments are tested as soon as possible and those not suitable are returned to the sender. So far, only 5 per cent have been found unsuitable. Instruments somewhat out of repair will be accepted as there is a repair department in the Naval Observatory. A glass with a slight chip may pass the test, but the glasses must be of a good grade.

Upon acceptance of the glass, sextant or chronometer, you will be sent a letter of thanks, signed by Franklin D. Roosevelt, Assistant Secretary of the Navy. A check for $1 will be sent you, which sum will constitute the rental price, or in event of loss, the purchase price of the article.

The instrument is then entered in the records at the Naval Observatory with your name, address, and key number. A metal tag with your name and address is securely attached by wire to the instrument and, as an additional safeguard, your key number is engraved on the inside of the instrument. The instruments are then shipped in lots and distributed among the commandants who in turn distribute them, taking a receipt for each instrument, just as is done with all other Navy property.

While it is, of course, impossible to guarantee your glass, sextant or chronometer, against damage or loss, every precaution has been taken for its return at the close of the war. The only precaution the sender needs to take is to notify the Naval Observatory of any change of address, or to see that mail being sent to the old address will be properly forwarded at the close of the war."

Things to note here are that sextants were among the items that the public was being asked to donate; that donated items were sent to Franklin D. Roosevelt, c/o the U.S. Naval Observatory, where they were inspected for usability; and, that Naval Observatory engraved a ‘key number’ on equipment accepted for use.  It’s tempting to think that the ‘R’ in the ‘RO’ symbol on the five sextants signifies that they were donated by civilians through the program led by a man whose last name begins with the letter ‘R’; the Naval Observatory’s Annual Report for Fiscal Year 1919 refers to the donated equipment as “Roosevelt Glasses”, which suggests that at the Naval Observatory, Roosevelt was very much associated with the donated equipment.  The Fiscal Year 1919 Annual Report states that some 52,000 donated binocular and spyglasses had been received and inspected at the Naval Observatory, of which some 32,000 had been accepted for use.  A serial number series extending to five digits would have been needed to track that number of donated equipment [12].

In another part of the memo, the organization’s director wrote the following about what the Eyes for the Navy campaign had already achieved by the February, 1918 date of the memo:

Many remarkable binoculars, spyglasses, telescopes, chronometers, and sextants have been received. Among these are many that have historic interest dating back to the Spanish, Civil, and Mexican Wars, even the War of 1812, and a few from the Revolution— these glasses have already done their bit. They are coming to the Navy now for use in this greatest of all wars; they are coming from men of science, from travelers, from sportsmen, from men who have had a good glass lying idle for years and years.

Who will want to keep a glass for a little selfish amusement when it can serve such a serious and such a great purpose? Who will dare appear in public with a glass, after the Navy needs are known.

Wm. McCormick Blair, Director, Four Minute Men

This confirms that sextants were indeed among the items the U.S. Navy received through the Eyes for the Navy program.  Perhaps the Gifford, Hooker, and Davidson sextants were the kind of things Blair was referring to in his comment on the age and historical interest of some of the donated nautical equipment.
So, a pretty strong circumstantial case can be built around the idea that the five sextants were donated to the U.S. Navy through the Eyes for the Navy campaign.  This idea provides a plausible explanation for the NR symbols and the five-digit serial numbers they are marked with, and why the Navy had in its possession sextants that weren’t American-made to U.S. Navy specifications (i.e., civilians were under no obligation to buy sextants made to government specifications).  What I had missed until a couple of weeks ago was that I had in my possession a piece of evidence that makes this case rather definitive.  While trying to put my collection of sextant photos into better order, I happened to take a look at a photo of the side of the box for the George Davidson sextant displayed at the Paris Exhibition of 1867.  That photo,reproduced below, shows a shipping label indicating that the box was sent by T.D. Davidson of San Francisco, California to  ‘Hon. F.D. Roosevelt, Naval Observatory, Washington D.C.’, i.e., the address to which the Eyes for the Navy campaign instructed the public to send donated nautical equipment.

Shipping Label on the George Davidson Sextant Box

Comments, corrections, additional relevant facts, differing viewpoints, etc., are always welcome.  Send to
[1] A photo of this sextant box can be seen at the TIGHAR web site.  Go to  I suspect that this sextant box may date to the very late 19th century.
[2] This according to the catalog description of a very similar-looking sextant in the Smithsonian Museum’s Behring collection.  See:
[3] The New Bedford Whaling Museum’s online catalog of its holdings can be found at:
The RO symbol is described as a registered trademark symbol in a museum catalog pdf file I downloded at:
[4] This according to a web page of the Smithsonian Museum’s Behring Center:  Earlier and later in the 19th century, Spencer, Browning & Co operated under similar names.
[5]  Skinner Auctions online catalog:
[6] Rock Island Auction Company online catalog:
[7] Skinner Auction online catalog:
[8] A history of the firm Eggert & Son can be found on pages 375-376 of: Marine Chronometers at Greenwich: A Catalogue of Marine Chronometers at the National Maritime Museum, Greenwich (Oxford University Press).  This book can be read online at Google Books.
[9] A competitive bidding process involving sealed bids is referred to in an October 10, 1917 article in  Jeweler’s Circular Weekly.  A copy of that article can be seen in an earlier post titled “What to the Numbers 3500 and 1542 Tell Us? Part Three”.  How the sextant acquisition process worked at the turn of the 19th Century is described in the Department of Nautical Instruments section of the Report of the Superintendent of the United States Naval Observatory dated July 1, 1898: 
“The purchase of sextants by award of contract to the lowest bidder was so far modified to invite instrument makers to submit sextants made in accordance with careful specifications, the contract to be awarded at a stated price to the maker whose work showed the highest accuracy and perfection of work. Four firms submitted a sample of sextant of the two classes called for (a high-grade sextant at $100 and a surveying sextant at $90), with the exception of Warner & Swasey, who submitted only s high-grade sextant.  As a result of the competition, the contract for the high-grade sextant was awarded to Warner & Swasey, of Cleveland, Ohio, and for the surveying sextant to F.E. Brandis, Sons & Co of Brooklyn, N.Y.
[10] Page 8 of the U.S. Naval Observatory’s Annual Report for Fiscal Year 1918 reports on a ‘drive for glasses’ overseen by Assistant Navy Secretary Roosevelt.  Page 6 of the report explains that at the outset of the war, American manufacturers were unable to produce needed items at a sufficient pace, and that the production of optical glass at a sufficient rate to meet needs was a particular problem.
[11] A copy of the Four Minute Men memo can be viewed in the digital collection of the University of Colorado at Boulder:
[12] The numbers stated in the report would seem to be rounded to the nearest thousands; while the numbers are said to be for ‘glasses’, I suspect that they are for all types of equipment.  The serial number of the Captain Hooker sextant, RO 31518, is the highest of the five sextants discussed here, looks to be close to the end of the RO serial number series.