The sonnet has remained, since its introduction into English poetry, a favorite form among poets and critics, but has never become genuinely popular. It is suited, of course, only for the expression of dignified and careful thinking; and the difficulty of giving it unity and confining the content to the precise limit of fourteen lines has made perfect success in the form a rare attainment. Furthermore, the complexity of the rime-scheme--the distance at which one rime responds to another--makes the appreciation of the form a matter of some delicacy, less suited to the prevailingly simple taste of the English ear than to the more complex taste of the Italian. The following specimens are classified only in the two principal groups of the Italian and the English form. The common test of the Italian form is that the rime-scheme shall separate the first eight lines from the rest, these eight lines ordinarily showing "inclusive rime" of the _abba_ type; the test of the English form is that the rime-scheme shall separate the first twelve lines from the last two, the twelve lines ordinarily showing alternate rime. Schipper groups English sonnets in five classes: (1) the strict Italian form, with pause between octave and sestet; (2) the Surrey-Shakspere or English form; (3) the Spenserian form; (4) the Miltonic form, with correct rime-arrangement but general neglect of the bipartite structure; (5) the modern Italian or Wordsworthian form, following the regular rime-scheme in general, but often with a third or even a fourth rime in the octave, and treated as a single strophe. (_Englische Metrik_, vol. ii. p. 878.)[36] A.--THE REGULAR (ITALIAN) SONNET In this group the student of the subject should note the detailed variations of the rime-scheme of the sestet, and the varying practice of the poets as to the division between octave and sestet. In view of the connection of Petrarch's sonnets with Wyatt's introduction of the form into England, the first of them is reproduced as a typical specimen of the strict Italian form. Voi ch' ascoltate in rime sparse il suono Di quei sospiri ond' io nudriva 'l core In su 'l mio primo giovenile errore, Quand' era in parte altr' uom da quel ch' i' sono, Del vario stile, in ch' io piango e ragiono Fra le vane speranze e 'l van dolore, Ove sia chi per prova intenda amore Spero trovar pietà, non che perdono. Ma ben veggi' or sí come al popol tutto Favola fui gran tempo, onde sovente Di me medesmo meco mi vergogno; E del mio vaneggiar vergogna è 'l frutto, E 'l pentirsi, e 'l conoscer chiaramente Che quanto piace al mondo è breve sogno. (PETRARCA: _Sonetto_ i.)