I don't get much chance to post here these days, but I see you have been busy . . . However, Marc Sparcster asked me about a style of waterproof case which isn't seen too often, and I thought others might be interested too, so I dug out one of mine and made some new pictures. Please forgive me if this is old hat and has been discussed here before.
A brutally simple way of protecting a watch was to place it completely inside a larger case, with a screw-down bezel forming an hermetic seal and totally protecting the watch within. Once the bezel was unscrewed, the watch flipped out on a hinge to allow the movement to be wound and the hands set. Watches employing this double case design are usually called "Hermetic". I will begin by describing one of these watches, and then go on to the origin of the design. Here is a picture of one of my watches with a hermetic case. The thing that immediately strikes you as odd when you see one of these is that there is no visible crown.
Unscrewing the bezel reveals the watch inside the outer case, and you can now see the crown, although you can't turn it.
A little projection at 5 o'clock on the inner case allows you to use a finger nail and raise the inner watch so that you can get at the crown to wind the watch and set the hands in the normal way.
The inside back of the outer case carries the François Borgel FB-key trademark, at this time used by the company of Taubert & Fils, who bought the Borgel company from François' daughter Louisa in 1924 and carried on using the same trademark. It also has the mark of the two "F"s lying one on top of the other used by the Glasgow Assay Office for imported items, the date letter "g" indicating the hallmarking year of 1 July 1929 to 30 June 1930, the "935" verifying silver of at least Sterling grade, and the sponsor's mark "R&S", registered to Rotherham & Sons.
The inner watch has its own snap-on case back. Removing that reveals the movement. The movement is clearly Swiss and says "Swiss made" but is also stamped with the Rotherham & Sons R&S mark.
The firm of Rotherham & Sons, based at various numbers of Spon Street, Coventry, Warwickshire, UK, could trace its origins back to 1747 to a firm started by Samuel Vale. Richard Kevitt Rotherham joined the firm as an apprentice, and was listed as a partner in Vale and Rotherham in 1790. The firm was listed as Rotherham & Sons from 1850. They made entire watches: movements and cases. In 1858 Charles Dickens visited the factory and was presented with a watch to mark the occasion. By the 1880s Rotherhams were operating on a very large scale by British standards, with over 500 employees active in the production of both movements and cases.
The Swiss got rather a shock at the Philadelphia exhibition in 1876 when they saw how far the American watch industry had gone in producing watches by machinery on the interchangeable and gauged system. As a result of this, the Swiss increased their use of machinery to compete with the Americans, and although there were some attempts in England to mechanise and automate watch making, they were too little and too late. Although Rotherhams were a big company by British standards, they couldn't compete with the Swiss and American factories and around the turn of the century they started to diversify out of watch making into making parts for the Coventry bicycle and motor industry. During the first World War (WW1) they went entirely over to war work, and it is not clear whether they returned to watch making after the war. They certainly carried on making clocks, and they imported watches like mine from Switzerland. Rotherham's Coventry machinery and designs were almost certainly for pocket watches only, and the sudden change in fashion during the war (WW1) to the wrist watch wrong footed them. There was little point in trying to develop their own design of wrist watch after the war, because they would find it even more difficult to compete with the established Swiss and American factories than they had before the war.
Cutmore in "Watches 1850-1980" states that British Industry Fair reports show that in 1920 and 1921 they showed at trade exhibitions cases for movements made in "their own factory in Switzerland." Cutmore suggests that this could possibly be the Rode Watch Company of La Chaux de Fonds, whose watches they marketed, but I have seen no evidence to back up this suggestion. In 1932 they became agents for Buren, and later Ulysee Nardin. In 1973 the company was incorporated into Cornercroft Engineering.
The origin of the hermetic case design is a bit of a puzzle because there are two virtually identical patents for the idea. One U.S. patent by Frederick Gruen, "Wrist-Watch" patent number U.S. 1,303,888 with a priority date of May 29, 1918, published May 20, 1919, and another later Swiss patent by Jean Finger, a watch case maker of Longeau, Berne, Switzerland, "Montre a remontoire avec boitier protecteur" (watch winder with protective box) patent number CH 89276 with a priority date of 4 January 1921, published 2 May 1921. The image shows figures from the two patents and you can see how similar they are. As far as I can see, the principal difference between these two patents is that the Gruen watch is hooked in and easily removable, whereas the Finger watch is hinged to the case. Apart from that, they are essentially the same. My Rotherham & Sons watch is made to the Finger design.
How do two such similar patents get issued within three years of each other? International patent treaties in force at the time should have protected inventions in other countries. Patent examiners have a duty to do due diligence to ensure that patents are neither obvious nor duplicate existing inventions, wherever that "prior art” exists. But during the period of these patents, means of communication and search were not so sophisticated as now, and foreign ofﬁces do not necessarily track each other very well, even today. Ultimately, patent law is based on litigation. If the holder of the priority patent does not realize the existence of the later patent, or chooses not to litigate, nothing happens. The Gruen patent was issued while the First World War was still raging, and communication with Switzerland would have been even more difficult than usual. It may be that Finger never saw Gruen's patent, and maybe by the time of Finger's patent, Gruen had given up on the idea or just never heard about it. Perhaps it is not so surprising that the two patents are so similar: as I remarked before, the idea is brutally simple.
Although the hermetic case achieved the desired waterproof effect, it had the major drawback that the bezel of the outer case had to be unscrewed every day so that the watch could be wound. Apart from being a nuisance to the owner, the case threads and the milling on the bezel wore quite quickly from this continuous use, so this was a far from ideal solution. However, despite these drawbacks, a number of manufacturers including Zenith, Eberhard and Rolex produced watches using this case design. It was very useful in the tropics where the heat and damp quickly corroded the movements of watches in ordinary cases, and hermetically sealed watches are sometimes referred to as "tropical watches" because of this.
It appears that Hans Wilsdorf, co-founder and managing director of Rolex liked the Jean Finger design and bought rights to the patent, because he registered exactly the same case design on May 26, 1922, under British patent GB 197208 "Improvements in and Relating to Watches," published May 10, 1928. A Rolex watch with the hermetic case was produced from 1924. Some Rolex Hermetic cases bear the initials JF for Jean Finger and were evidently made by Finger, also carrying the words "Double Boitier Brevet 89276" (Double Case Patent 89276), a reference to the Finger patent. The existence of the patent doesn't seem to have precluded other manufacturers producing watches using the same case design, such as Taubert & Fils who made the case of my watch. The patent would have had, I think, a 15 year life - the other manufacturers must have paid royalties to Finger (or maybe Wilsdorf?) to use the design.
The introduction in 1926 of the waterproof Rolex Oyster clearly didn't succeed in sweeping this case design away overnight. As we have seen, my watch dates to 1929/30. It was probably a cheaper alternative to the Rolex Oyster. Jean Finger evidently retained faith in his design, because he registered a slightly improved version of his original 1921 patent on 2 February 1929, Swiss patent number CH 138224, published 16 April 1930. By then though the end of the road for this design was clearly in sight.
Regards - David