Charles Nicholson (1795–1837), was a Liverpool-born flutist and composer, who performed regularly in London. Nicholson used a flute made by George Astor & Co., a London-based firm operating from c1778 to c1831. His father, also a celebrated flutist, modified the instrument, by lining the wood headpiece with metal, enlarging the embouchure and tone holes. All with a view to making the flute’s tone more powerful, yet still delicate and permitting the usual fingerings in the third octave, facilitating glides and vibratos.
The story goes…
Today Nicholson is remembered less for the special quality of his own personal style of music-making than for the fact that Theobald Boehm, on a visit to London in 1831, was impressed enough with his powerful tone that he felt he needed to build a new flute. The immediate result was Boehm’s model of 1831, which provided the earliest recognizable acoustical model for the modern flute. Taken from –
http://www.flutehistory.com/Players/Charles_Nicholson/index.php3