Asmus Johannsen Hamburg Geestemünde Chronometer Age Determination
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Asmus Johannsen was a North German watchmaker and chronometer maker , active in Altona / Hamburg , later possibly in Geestemünde .
Active period: approx. 1870 – 1910 .
He demonstrably delivered:
-
- Ship and deck chronometers (partly for the Imperial Navy),
- Pocket watches and precision watches engraved with “A. Johannsen” or “Asmus Johannsen Altona” .
His signatures and serial numbers appear in old chronometer lists and in museums (e.g., the German Watch Museum Glashütte).
In many cases, Johannsen worked as a regulator or finisher , completing and adjusting unfinished Swiss or Hamburg rough-cut pieces.
Typical engravings & signatures
| Engraving / lettering | Period | remark |
|---|---|---|
| “Asmus Johannsen Altona” | ca. 1870–1890 | classic hand engraving, usually on the brass movement or dust cover |
| “A. Johannsen Hamburg” | ca. 1885–1905 | frequently found in deck and ship chronometers |
| “A. Johannsen Geestemünde” | ca. 1895–1910 | Late phase, often marine chronometers in mahogany cases |
Serial numbers & dating tables
The serial numbers (excerpts from chronometer registers and museum holdings) provide a good orientation:
| Serial number | Estimated year of construction | Typical model |
|---|---|---|
| Nos. 1 – 100 | ca. 1870–1885 | early pocket watches, key-wound, enamel dial |
| Nos. 100 – 300 | ca. 1885–1895 | Chronometers and deck clocks with Swiss ebauche movements (Frodsham or Kullberg type) |
| Nos. 300 – 600 | ca. 1895–1905 | Marine chronometer, spring chronometer, Geestemünde engraving |
| Nos. 600 – 800 + | ca. 1905–1910 | late works or subsequent works |
Johannsen did not use an industrially standardized numbering system. The numbers are serial numbers from his own assembly/regulation process , not necessarily from sequential series production.
External identifying features (check time period)
| feature | Reference to time period |
|---|---|
| Key-wound, Roman numerals, enamel dial | before 1885 |
| Crown winding mechanism, Arabic numerals, silver case (800 hallmark) | ca. 1885 – 1905 |
| Chronometer in a wooden case, dial with seconds display at 6 o'clock | 1895 – 1910 |
| Signature “Geestemünde” or “Bremerhaven” | latest phase |
| Engraving / Find | Old |
|---|---|
| “Asmus Johannsen Altona No. 82” | around 1880 – 1885 |
| “A. Johannsen Hamburg No. 245” | ca. 1890 – 1895 |
| “A. Johannsen Geestemünde No. 412” | ca. 1898 – 1903 |
| “A. Johannsen Geestemünde No. 635” | ca. 1907 – 1910 |
Johannsen, Asmus
( English chronometer maker)
Asmus Johannsen was born in Denmark (then Schleswig, Germany) in 1826. He moved to London and worked as a watchmaker from 1856 onwards, founding the company Asmus Johannsen in 1859. From about 1856 to 1872, his business was located at 38 Holford Square.
From 1862, Asmus Johannsen worked with his nephew Christian Carl Lorenzen . The company then operated as A. Johannsen & Co. In 1872 , the company relocated to Minories 149 in London (show this location) . In 1916 , the company won two first prizes at the Greenwich Chronometer Trials. The company was also very successful at Kew's trials, and in 1923, A. Johannsen & Co. won a group prize at the Breguet Centenary Exhibition in Neuchâtel.
The Dutch chronometer maker Abraham de Casseres completed his training around 1853 at A. Johannsen & Co. The company was a supplier of chronometers to the British Admiralty, the Government of India, the Royal Navy of Italy, Spain, and Portugal, as well as the US Navy.
Asmus Johannsen first lived at 119 Minories, later at 45 Lyndhurst Grove. He presumably died in 1882 , although another source gives 1920 as his year of death. In any case, Lorenzen continued to run the business after Asmus's death until he too passed away in 1935. LHC Lorenzen took over the business, and the company A. Johannsen & Co. was dissolved in 1940 .
