The Couesnon 1900
Here's a listing of all the early Couesnon model names, from "deluxe model" to "standard model", modifying the New Langwill Index to fit reality:
- Modele Monopole ("elaborately" engraved)
- Opera (Series HN)
- Armee (Series BN) or FourMsseursDeL'Armee
- Armee (Series GNM)
- National (Series BO)
- Universel (Series CGO)
- Modele SO (or Series SO)
- (some models may be unmarked)
I don't have an exact idea, because I don't have enough examples, but it may also be the case that the "lower" models had dual-octave key and lacked pearl keytouches after 1913.
I am not sure when Couesnon switched from split-bell-keys to left-hand-bell keys. It's even possible that there was a switch only on the upper models, or upper models were switched first.
According to the New Langwill index, the date for these horns is found by looking at the number in the "grenade" ("pineapple") on the bell, so, e.g., "8" would mean "made in 1908".
The main reason I call these "1900" models: a lot of them have "hidden" serial numbers (under a key, or some such), rather than on the bell, but you can always see an engraving on the bell that says (translated), "Universal Exhibition of Paris, 1900" -- and it's a lot easier than remembering the Series names.
These horns have a very sweet sound -- I owned a "1900" bari -- but a lot are high pitch horns (Couesnons aren't labelled LP or HP.)
This is the only other model I know of to use bevelled tone holes. The other is Martin -- and they're significantly different.
Finally, a major note: post-1937 have a different label and address on the bell: "Couesnon SA, 105 rue Lafayette"