Page "Orchestra" Paragraph 154

The invention of the piston and rotary valve by Heinrich Stölzel and Friedrich Blühmel, both Silesians, in 1815, was the first in a series of innovations, including the development of modern keywork for the flute by Theobald Boehm and the innovations of Adolphe Sax in the woodwinds.

These advances would lead Hector Berlioz to write a landmark book on instrumentation, which was the first systematic treatise on the use of instrumental sound as an expressive element of music.