Kandinsky, himself an accomplished musician, once said Color is the keyboard, the eyes are the harmonies, the soul is the piano with many strings. The artist is the hand that plays, touching one key or another, to cause vibrations in the soul. The concept that color and musical harmony are linked has a long history, intriguing scientists such as Sir Isaac Newton. Kandinsky used color in a highly theoretical way associating tone with timbre (the sound's character), hue with pitch, and saturation with the volume of sound. He even claimed that when he saw color he heard music.