He knew that his memory of the piano falsified still further the perspective in which he saw the music, that the field open to the musician is not a miserable stave of seven notes, but an immeasurable keyboard (still, almost all of it, unknown), on which, here and there only, separated by the gross darkness of its unexplored tracts, some few among the millions of keys, keys of tenderness, of passion, of courage, of serenity, which compose it, each one differing from all the rest as one universe differs from another, have been discovered by certain great artists who do us the service, when they awaken in us the emotion corresponding to the theme which they have found, of shewing us what richness, what variety lies hidden, unknown to us, in that great black impenetrable night, discouraging exploration, of our soul, which we have been content to regard as valueless and waste and void.