56.  Far-fetched though this idea will perhaps be thought, a little introspection will countenance it.  That we do take advantage of metrical language to adjust our perceptive faculties to the force of the expected articulations, is clear from the fact that we are balked by halting versification.  Much as at the bottom of a flight of stairs, a step more or less than we counted upon gives us a shock; so, too, does a misplaced accent or a supernumerary syllable.  In the one case, we know that there is an erroneous preadjustment; and we can scarcely doubt that there is one in the other.  But if we habitually preadjust our perceptions to the measured movement of verse, the physical analogy above given renders it probable that by so doing we economize attention; and hence that metrical language is more effective than prose, because it enables us to do this.

57.  Were there space, it might be worthwhile to inquire whether the pleasure we take in rhyme, and also that which we take in euphony, axe not partly ascribable to the same general cause.

PART II.

CAUSES OF FORCE IN LANGUAGE WHICH DEPEND UPON ECONOMY OF THE MENTAL SENSIBILITIES.

i.  The Law of Mental Exhaustion and Repair.

58.  A few paragraphs only, can be devoted to a second division of our subject that here presents itself.  To pursue in detail the laws of effect, as applying to the larger features of composition, would carry us beyond our limits.  But we may briefly indicate a further aspect of the general principle hitherto traced out, and hint a few of its wider applications.

59.  Thus far, then, we have considered only those causes of force in language which depend upon economy of the mental energies: we have now to glance at those which depend upon economy of the mental sensibilities. Questionable though this division may be as a psychological one, it will yet serve roughly to indicate the remaining field of investigation.  It will suggest that besides considering the extent to which any faculty or group of faculties is tasked in receiving a form of words and realizing its contained idea, we have to consider the state in which this faculty or group of faculties is left; and how the reception of subsequent sentences and images will be influenced by that state.  Without going at length into so wide a topic as the exercise of faculties and its reactive effects, it will be sufficient here to call to mind that every faculty (when in a state of normal activity) is most capable at the outset; and that the change in its condition, which ends in what we term exhaustion, begins simultaneously with its exercise.  This generalization, with which we are all familiar in our bodily experiences, and which our daily language recognizes as true of the mind as a whole, is equally true of each mental power, from the simplest of the senses to the most complex of the sentiments.  If we