[15] On the subject of Tone-color in English verse, see Guest's _English Rhythms_, chap. ii.; Lanier's _Science of English Verse_, part iii. ("Colors of English Verse"); Corson's _Primer of English Verse_ (chapter on "Poetic Unities"); Edmund Gurney's _Tertium Quid_ (essays on "Poets, Critics, and Class-Lists" and "The Appreciation of Poetry"); Professor J. J. Sylvester's _Laws of Verse_ (London, 1870); G. L. Raymond's _Poetry as a Representative Art_ and _Rhythm and Harmony in Poetry and Music_; and Ehrenfeld's _Studien zur Theorie des Reims_. PART TWO I. FOUR-STRESS VERSE English verse of four stresses is chiefly to be divided into two groups: that representing the primitive Germanic tendency to emphasize the element of accent rather than the counting of syllables, and that produced under foreign influence, showing comparative regularity in the number of syllables to the verse. The first group is made up of the various descendants of the original "long line," sometimes rimed and sometimes unrimed; the second group of forms of the familiar octosyllabic couplet. (Of modern verse only iambic measures are included here.) A.--NON-SYLLABLE-COUNTING The earliest English verse, like early Germanic verse generally, is based on the recurrence of strong accents, and is composed of a long line made up of two short lines, or half-lines, which are bound together by alliteration. As to the number of accents to be counted in the line, there are two theories, the "two-accent" and the "four-accent." According to the first, we should count two accents to the half-line, and four to the long line; according to the second, we should count four to the half-line and eight to the long line. The distinction is not so marked, however, as would appear at first thought; for the two-accent theorists recognize a considerable number of secondary accents in addition to the principal ones, while the four-accent theorists recognize half the accents as being commonly weaker than the other half. The four-accent theory is that of Lachmann, represented chiefly in more recent scholarship by ten Brink and Kaluza. Lachmann took, as the typical Germanic line, such a verse as this from the _Hildebrandlied_,-- "Garutun se iro guðhama: gurtun sih iro suert ana;"