The piano, as distinct from the harp

Beethoven on the development of the piano as an instrument in its own right:

There is no doubt that so far as the manner of playing it is concerned, the pianoforte is still the least studied and developed of all instruments; often one thinks that one is merely listening to a harp.  And I am delighted, my dear fellow, that you are one of the few who realize and perceive that, provided one can feel the music, one can also make the pianoforte sing.  I hope that the time will come when the harp and pianoforte will be treated as two entirely different instruments.

Beethoven, in a letter to Johann Andreas Streicher, 1796.

Anderson, Emily, ed. (1961) The Letters of Beethoven.  3 Vol., London: St. Martin’s Press.  Letter 18.  Cited in: Marek, George (1969) Beethoven: Biography of a Genius.  London: William Kimber, p.161.