Only as a result of recent investigations can a satisfactory theory of modern verse be constructed. The making of this theory has been largely hampered, on the one hand, by the application of the quantitative principles of classical verse to our poetry; and, on the other hand, by forcing the analogy between music and verse. The insufficiency of the quantitative scheme for English verse is not difficult to perceive. Such a scheme presupposes that syllables have a fixed quantity of duration, as either long or short, and that rhythm consists in the regularity of their distribution. But, although there are differences in the duration of syllables, some being longer than others, there are no fixed rules to determine whether a syllable is short or long; and, what is a more serious objection, it is impossible to find any regularity in the occurrence of shorts and longs in normal English verse,--in all verse that has not been written with the explicit purpose of imitating the Greek or Latin. An examination of any line of verse will verify these statements. Take, for example, the first three lines of Shakespeare's song, Blow, blow, thou winter wind, Thou art not so unkind As man's ingratitude. Here the quantitative scansion is perhaps as follows:-- - - - - U - - - U x U - U - U - U - I have given the word "so" a double scansion because I conceive it impossible to determine whether it is really long or short. At any rate, there is certainly no regularity in the distribution of shorts and longs, except in the last of the three lines, and no correspondence, except in that line, between the quantitative scansion and the rhythmical movement of the verses. And whenever such a correspondence exists, it is due either to the fact that the incidence of stress tends to lengthen a syllable or to the fact that, oftentimes, in polysyllabic words, mere length will produce a stress. This is the modicum of truth in the quantitative view. But obviously stress governs, quantity obeys.