Now it is quite true that the _attention_ can be fixed on only one feeling at any given moment, and that the stronger crowds out the weaker so far as the attention is concerned: yet this does not prevent the prevailing feeling from being affected by the echo of the one which preceded it. If a man, buried in the labyrinths of a big hotel, is waked up in the night by cries of fire; though it may prove a false alarm, yet the effect of the fright will remain with him and cast a gloom over his whole day’s doings, however pleasant in themselves. And a doubtful lover’s enjoyment of his sweetheart’s sweetest smiles is often galled by the remembrance that on the preceding day she smiled just as sweetly on his odious rival. “For sorrow ends not when it seemeth done,” says Shakspere. In his admirable _Dissertation on the Passions_, Hume cleverly makes use of a musical analogy to explain how different emotions may be mixed: “If we consider the human mind, we shall observe that, with regard to the passions, it is not like a wind-instrument of music, which, in running over all the notes, immediately loses the sound when the breath ceases; but rather resembles a string-instrument, where, after each stroke, the vibrations still retain some sound which gradually and insensibly decays. The imagination is extremely quick and agile, but the passions in comparison are slow and restive; for which reason, when any object is presented which affords a variety of views to the one and emotions to the other, though the fancy may change its views with great celerity, each stroke will not produce a clear and distinct note of passion, but the one passion will always be mixt and confounded with the other.”