Re: A. Willman & Co. Vienna Regulator Clock
Albra, thanks for your kind words. My efforts at dating various makers' clocks by way of using serial numbers as a primary marker has uncovered many things that were previously unknown, or based on hearsay and other false information, or simply ignored because "serial numbers have no meaning".
However, serial numbers are only one of many parameters that I record and use for confirmation of dating estimates. At a minimum, the following are also used for each and every maker where I undertake to create a serial number dating correlation:
1) Known commercial events:
These include such information as the founding of a company, bankruptcy proceedings, known economic recessions, closure notices, moves from one location to another, opening of more than one factory where a new or different serial number system may be used, expansions or closures, etc.
2) Trade advertisements and articles:
These include dated advertisements showing the products of the company as well as critical information such as logos and trademark dates, addresses, and the like. The publishing of the AJU, DUZ, and Keystone has greatly facilitated this effort, in fact the amount of information now available from these three sources alone is almost overwhelming.
3) Sale catalogs:
The more the merrier, especially when dated. These profusely illustrate the company's products, designs, patents, etc. and when you have multiple year editions you can track the model and style changes.
4) Patent information:
Doug Stevenson's effort to publish a complete set of the patent announcements from the DUZ, from 1877 to 1932, has been a godsend. I only wish it was digitized so I could search it by computer instead of manually. The patent search sites now available also give us access to many patents not available just a few years back. Knowing a patent grant date will provide a "not earlier than" date of manufacture, since the patent number is unknown until that date and if present on a clock or the item patented can be readily identified, you that the serial number associated with the patent will give you an "anchor point" in the data correlation. Patent expiry dates are quite amorphous and thus not nearly as good for dating but are useful for early estimates and later correlations.
5) Dated Presentation Inscriptions
These give you a "not later than" date that can be very useful. A very few presentations are found that are made years after the clock is made, however the huge majority are within a year or two of the actual manufacturing date and when you have multiple such inscriptions they provide a lot of glue to tie the overall correlations together.
6) Spreadsheet and Database use
For each maker I record from 20 to 30 data points for each clock that describe the following individual features: Movement type and layout, back plate number, movement support bracket and gong, suspension guard type, upper suspension bracket, escapement design, crutch design, pendulum support design, pendulum design, case design, case model number if known, bezel design and finish, dial design and features (size, type of numbers, type of hands, whether one or two pieces, what material, inscriptions and logos if present and other info), any dated item, patent numbers, and of course serial numbers.
Fundamentally all the above six areas of info is collected in my databases for each maker, of which I now have twenty-four compilations. I also have for each maker a "historical archive" where I compile all known information about that maker, quite a bit of which is linked or referenced to specific publications. There is also a patent database where I have compiled known patents of interest that are very useful for establishing dating anchor points.
The beauty of compiling all this information in a spreadsheet by serial number sequence, is that for those makers who followed sequential serial numbering you can CLEARLY see every major transition of design, patent feature, style, case model numbers and many other features. This also quickly sorts out the question of variance of serial numbering because of using different systems for different types of clock movements. One of the best examples I have is that I found that GB kept a separate set of serial numbers for their alarm clocks made at the Freiburg factory. Too lengthy to explain here but believe me it is so.
This also quickly sorts out the question of what was the beginning serial number for a given maker's clocks. Here are examples:
JUF: Serial numbers were used for the Harder patent clocks made from 1882 to 1888 (patent stamps only to June 1887), but discontinued for the next 20 years. In 1907, serial numbers were resumed at 50001, which happens to be very close to the total number of 400-Day clocks made by JUF up to that date. Sequential numbers were maintained until the end of 1922 at about 172000, then discontinued for the remainder of the company's history.
Ph. Hauck: Serial numbers started at less than 100 in 1903 (lowest number to date is 16) when they started production, continuing sequentially to stopping of production at the end of 1914, highest serial number to date 43900.
Kienzle: Serial numbers for their massiv 400-Day movements started at 100001 about 3rd quarter 1907, and continued uninterrupted to the sale of their business to Kern & Link in 1929, highest number to date 187250. Note that Kienzle made "special runs" of their massiv movements for third parties including Huber Uhren and Selsi, these all had low (five digits or less) serial numbers. Further, Huber patent lantern pinion clocks made for Kienzle had a separate set of serial numbers starting below 1000 in 1913 and finishing above 47250 in 1927 or early 1928 when Huber stopped manufacture of these movements.
Gustav Becker: Separate serial numbering was kept at Freiburg and Braunau. Freiburg had consecutive serial numbering for all types of clocks except alarm clocks and Amerikaner movements (no serial numbers for Freiburg), starting below 1000 around 1850-52 and continuing to just under 2510000 by mid-1925, when the old system was discontinued and separate numbers starting with "1" were set up for at least four types of clocks. These continued until the Freiburg factory shut down at the end of 1932. The Braunau factory started with numbers under 1000 in early 1888 and continued using consecutive serial numbers until mid-1925, the same time the Freiburg factory stopped them. The highest number for Braunau so far is 921794.
I also have serial number dating information developed for Anton Harder patent 400-Day clocks 1877-1887; W. Würth & Co (1903-1910); R. Schnekenburger from 1882 continuing to Uhrenfabrik Mühlheim Müller & Co. 1900-1913 as RSM logo, UMMC Lion following the October 1913 boiler explosion and continuing to 1932; Regulatorfabrik Germania 1871-1899; Uhrenfabrik Concordia 1881-1899; H. Endler 1865-1893+; A. Willmann 1871-1899; Eugéne Farcot Paris 1862-1890; Claude Grivolas Paris 400-Day clocks 1904-1914; Eureka London 1908-1914 (this one is messy); Gebrüder Junghans 400-Day clocks 1908-1914; Kieninger & Obergfell 400-Day clocks 1923-1939; Schlenker & Posner 400-Day clocks 1928-1939 (1938 & 1939 assembled by Kern & Söhne); Reutter Atmos 1930-1938; Atmos II 1939-1950; all other Atmos models from 1950 to present day; Konrad Mauch 1948-1950; Bulle-Clocks 1920-1954 in France and 1956-1970 in Brazil, and am developing others.
In all instances I look at movement types and designs and ask myself whether for a given maker some movements were made by others. I will discuss that point later as it merits its own topic or at least considerable expansion within the individual threads for a few makers.
When I quote an approximate manufacturing date for a given maker I do indicate the approximate accuracy as that can be quite different depending on the volume of data collected and many other factors. I also am quite ready to change my conclusions whenever I find new information that overrides previous conclusions. All my databases are subject to change and do get modified as new information comes available. Some are quite accurate, some are still only approximate but usually an order of magnitude better that what is commonly found on the Internet. I have published much of my 400-Day information only to the NAWCC 400-Day Chapter, the reason being that for the first several years I did this it was not uncommon to have frequent changes of data lines. It has been nearly 20 years since I started this effort, it is now time to decide which database gets made completely public. The Reutter Atmos data will likely be first, followed closely by Gustav Becker. After that will be several 400-Day clock makers and then the others that are relatively new on the block.
Finally, when I hear someone say that serial numbers don't make sense, I say "show me why". To my knowledge very few researchers have even attempted to compile sufficient data to be able to say that a given maker didn't follow any logic with their serial numbers. There is always the statement that French roulants can't be dated by serial number, but I've never seen proof of that. Au contraire, I have three French makers in my databases who definitively followed a sequential system, namely Eugéne Farcot, Claude Grivolas, and M. Favre-Bulle. I suspect that Henry Hatot also did but I don't have enough data to reach that conclusion.
I "do" know that many makers used separate serial number sequences for different movement designs or did other things that make it sometimes significantly difficult to reach any conclusion. On the other hand, with the proliferation of available data on the Internet, a dedicated researcher can compile dozens of examples of even rare clocks in a very short time frame. One good example is my Schnekenburger-UMMC database, that contained only 30 clocks just little over a year ago and now has nearly 300 examples with most of them coming from eBay. All it takes is dedication, patience, and perseverence to dig out the related info needed to corroborate such things as patent dates and corporate events such as you mentioned. It CAN be done!!