The nineteenth century was a time of great national differences in flute design, and in performance style and taste as well. For better or for worse, these differences are gone today. One cannot get a good overall view of the 19th century simple system flute by just studying the developement chronologically. It is necessary, I feel, to trace the changes in each country or region separately.
As an vast oversimplification, we will distinguish five regions:
We can start with two quotes from Rockstro (1889):
"The bore and finger holes, as made in Germany, were slightly larger than those adopted in France, but both French and German performers generally preferred a small, sweet tone to the powerful and rich one for which the English were celebrated, particularly in the lowest octave."
"Though the French flutes were undoubtedly inferior to those of England, and even to those of Germany, in intonation and tone, they were far superior in beauty of appearance.... [In] the construction of their keys, as well as the general excellence and elegance of their workmanship, they stood pre-eminent."We should take Rockstro's value judgements with a grain of salt, but his remarks on construction have some validity, and these trends are already present by 1820.
Actually, German and French bore and hole sizes seem, on the whole, about the same in the early 19th century; the differences appeared later. Some English flutes starting circa 1820 have extremely large finger holes. Shown below are the right hand finger holes on particular French, English, and German flutes from c.1820, by Tabard, Clementi (this instrument is from the Fiske Museum, Claremont, CA), and Piering, respectively.
Though the largest holes used in London never became popular elsewhere, English instruments and innovations had a great influence on instruments all over the western world. The English were large exporters of musical instruments and London-made instruments can be found almost everywhere.
The English influence is visible in Viennese instruments (e.g. early use of tuning heads and pewter plug keys). But the sounds and playing characteristics of the instruments are very different. The Viennese instruments can be very "colorful", if less rich and loud on the low notes. I am tempted to make an analogy between the differences in English and Viennese pianos in the 19th century, and the differences in English and Viennese flutes in the 19th century. Viennese pianos from the early 19th century are colorful and articulate, with quick damping, while English pianos provided more of a wash of sound, generally better for legato playing, but perhaps more bland and covering.
Understanding of the developement of simple system in Central and Eastern Europe is important for the understanding of flute music, orchestration, and opera from those areas of the world in the second half of the 19th century. Simple system flutes were still in serious use in these regions.
American flutes exhibit at first a very strong English influence, as one would expect. But there were other influences and some distinctly American touches.