Extant 'C. Nicholson's Improved' flutes
Clementi-stamped flutes without serial numbers are here allocated the arbitrary number 0000, and similar Prowse-stamped flutes XXXX. Flutes with low (3 digit) serial numbers are assigned a leading '0' to aid sorting, though of course this wasn't the practice on the flutes themselves. Flutes with unknown serial numbers are listed as NNNN. I suspect - based on style, fingerhole size, distribution of serial numbers of surviving flutes, etc - that the earliest few batches of flutes were not stamped with serial numbers. Clear manufacturing patterns emerge, with earlier, Clementi-stamped instruments - made under the supervision of Thomas Prowse senior - tending to have small fingerholes. These flutes were also supplied in numerous cases with two headjoints, the shorter usually pitched at A=452 with the barrel closed, and the longer working at somewhere just below A=440. Of course the acoustic design of these instruments was optimised for playing with the headjoints extended somewhat. A transition can be seen when Clementi & Co transmutes into Collard & Collard, which roughly coincides with the point at which flute manufacture moved from Thomas Prowse senior's supervision, to that of his son at the new Hanway Street Flute Manufactory. Thomas Prowse junior experimented more with the design of the instrument, and his flutes are more likely to have large fingerholes. By the later part of his manufacture, flutes often have a one piece body, sometimes with left and right hand fingerholes offset for ergonomic reasons. The very latest flutes begin to introduce pillar mounted keys, as used by Prowse junior on some of his other models of flute. Other trends which are identifiable are that earlier, Clementi-stamped, flutes are made in (6) 7 and 8 key models, and are as likely to have 'saltspoon' key cups for the C# and C keys as to have pewter plugs. As time goes on pewter plugs become ubiquitous (despite Nicholson apparently not liking them) as do long F keys (another Nicholson bete noire).
If you have details of an extant Nicholson's Improved flute, or corrections to the data below, which will be updated regularly, please contact me directly (see 'About/Contact' above). As I continue to work on the site links will become available (via the serial numbers in the list) to pages giving photos and additional details of the individual instruments.