What is the exact meaning of the phrase "Cataract of rippling notes"?

Question

I am reading the book "The story of my life" by Helen Keller. Many of the words, idioms and phrases are unfamiliar to me.

I have come across the phrase "Cataract of rippling notes". What does it mean? The meaning for each word is below

Cataract = a large waterfall
Rippling = a small wave or series of waves on the surface of water, esp. as caused by an object dropping into it or a slight breeze

I didn't found suitable meaning for note here. The most suitable for note here is below

Note = a particular quality or tone that reflects or expresses a mood or attitude

But when combining all of them I am getting the exact meaning. Then sentence is

What a joy it is to feel the soft, springy earth under my feet once more, to follow grassy roads that lead to ferny brooks where I can bathe my fingers in a cataract of rippling notes or to clamber over a stone wall into green fields that tumble and roll and climb in riotous gladness

Does it mean "A waterfall which is producing a kind of waves" or some thing like that?

Answer 1

It's really helpful you mentioned that this quote came from Helen Keller's autobiography because the metaphor makes more sense in light of her blindness and deafness. Because of her disabilities, the majority of her sensory input comes from touch, so she "hears" sounds by feeling the vibrations of objects that caused the sounds. In this sentence, notes probably refers to the sound from the rippling brooks. For her, the sound of a running stream is felt as a waterfall and waves on her fingers.