Oboe (With 17 Keys), Frédérik Triébert, Apollon-Marie-Rose Barret, Triebért Barret (rejected attribution), Triebért Barret (rejected attribution), c. 1860
The oboe underwent various changes in the 19th century. Extra keys extended both the instrument’s range, and corrected the intonation (purity) of certain notes. At the same time they afforded the tone greater uniformity. More keys also required a different fingering technique. In the second half of the century, the oboe evolved into the modern instrument, with fifteen or more keys.