A fourth mood distinguishable in Beethoven is the mood of mystery. He loves to suggest the illimitable and the transcendent, to dissolve himself in vagueness; to pique curiosity and stimulate imagination by long stretches of _pianissimo_, of amorphous, ambiguous harmony, of strange inarticulate melody that baffles the attention--long, wide hushes, audible silences. In these moods he seems to retire, after his onslaughts of expression, into the deep subterranean reservoirs of the unexpressed. The Introduction to the Fourth Symphony is an example; one hears in it, as it were, the groping of vast unorganized impulses that await a birth. The extended _pianissimo_ passage that leads into the Reprise, in the same movement, makes a similar impression, the modulation to the home-key of B-flat, after the long groping in B-major, seeming like the opening of a window in a darkened room. The wide stretches of rippling violin figures, _piano_, in the “Scene by the Brook” of the Pastoral Symphony illustrate another use of this device of monotony. They affect the mind, as Beethoven meant they should, like a placid sun-bathed landscape at noon, flat, silent, motionless. But perhaps the most striking instance of all is that wonderful page in the Fifth Symphony that prepares for the Finale. The sustained C’s of the strings, the suppressed, barely audible tapping of the drums in the rhythm of the central motif of the work, the fragmentary, aimless, and yet cumulative phrases of the violins, instil a sense of some vast catastrophe impending; and then, after the deliberate, gradual crescendo, pressing upon every nerve, the great joyous theme of the Finale crashes in, to sweep all before it.