There is, however, a still more pervasive incongruity between this temperament and the forms in which it expressed itself. Heine's love poems--two-thirds of the _Book of Songs_--are written in the very simplest of verses, mostly quatrains of easy and seemingly inevitable structure. Heine learned the art of making them from the _Magic Horn_, from Uhland, and from Eichendorff, and he carried the art to the highest pitch of virtuosity. They are the forms of the German Folk-song, a fit vehicle for homely sentiments and those elemental passions which come and go like the tide in a humble heart, because the humble heart is single and yields unresistingly to their flow. But Heine's heart was not single, his passion was complex, and the greatest of his ironies was his use of the most unsophisticated of forms for his most sophisticated substances. This, indeed, was what made his love poetry so novel and so piquant to his contemporaries; this is one of the qualities that keep it alive today; but it is a highly individual device which succeeded only with this individual; and that it was a device adopted from no lack of capacity in other measures appears from the perfection of Heine's sonnets and the incomparable free rhythmic verses of the _North Sea_ cycles. Taken all in all, _The Book of Songs_ was a unique collection, making much of little, and making it with an amazing economy of means. III Heine's first period, to 1831, when he was primarily a literary artist, nearly coincides with the epoch of the Restoration (1815-1830). Politically, this time was unproductive in Germany, and the very considerable activity in science, philosophy, poetry, painting, and other fine arts stood in no immediate relation to national exigencies. There was indeed plenty of agitation in the circles of the _Burschenschaft_, and there were sporadic efforts to obtain from reluctant princes the constitutions promised as a reward for the rising against Napoleon; but as a whole the people of the various states seemed passive, and whatever was accomplished was the work of individuals, with or without royal patronage, and, in the main, in continuation of romantic tendencies. But with the Revolution of July, 1830, the political situation in Germany became somewhat more acute, demands for emancipation took more tangible form, and the so-called "Young Germans "--Wienbarg, Gutzkow, Laube, Mundt, Börne, and others-endeavored in essays, novels, plays, and pamphlets to stir up public interest in questions of political, social, and religious reform.