In 1823 we see an echo of his passion for Amalie in his love for his younger cousin Therese, who seems in many respects to have been a replica of her elder sister. Therese, however, refused to be anything more than a cousin to him, and his heart was still further embittered as is shown by the poem:
"Wer zum erstenmale liebt
Sei's auch glücklos ist ein Gott
Aber wer zum zweitenmale
Glücklos liebt, er ist ein Narr
Ich, ein solcher Narr, ich liebe
Wieder ohne Gegenliebe;
Sonne, Mond und Sterne lachen
Und ich lache mit und sterbe."
In 1824 he decided to prosecute his studies for his doctorial degree with greater seriousness, and leaving behind him the distractions of the capital, went back once more to the more staid and prosaic Göttingen.
Heine intended not merely to take a degree for the sake of ornament, but also to practise seriously as a lawyer. How serious were these intentions may be seen from the fact that he went to the length of paying in advance the heavy entrance fee which the legal profession then exacted from Jews, and became baptized "as a Protestant and a Lutheran to boot" on June 28, 1825.
Heine's conversion has frequently been criticised with superfluous harshness. Let him, however, explain his position for himself:
"At that time I myself was still a god, and none of the positive religions had more value for me than another; I could only wear their uniforms as a matter of courtesy, on the same principle that the Emperor of Russia dresses himself up as an officer of the Prussian Guard when he honours his imperial cousin with a visit to Potsdam."
After all, his apostasy brought with it its own punishment, not only in its deep-felt shame, but in the fact that he eventually threw up law for literature, and thus rendered so great a sacrifice of racial loyalty and his own self-respect consummately futile. After selling his birthright he found that he had absolutely no use for the mess of pottage which he had purchased.
In the summer of 1825, Heine, having just succeeded in passing his degree, proceeded to the little island of Norderney, off the coast of Holland, to recuperate. Living ardently the simple life and indulging to the full his passion for the sea, he now wrote not only the second part of the Reisebilder, entitled Norderney, but the far greater Nordsee Cyklus, which in its irregular swinging metre expresses with such marvellous efficiency the whole roar and grandeur of the ocean. Speaking generally, of course, Heine was too subjective to be a real nature poet. No writer, it is true, fills up so freely and with so fantastic an elegance the blank cheques of nightingales and violets, lilies and roses, stars and moonshine, yet none the less these rather served to grace his measure than as his real flame. His one genuine love was the sea. With the sea he felt a deep psychological affinity. The sea was the symbol of his own infinite restlessness, of his own divine discontent, and mirrored in the sea's ever-changing waters he beheld the incessant smiles and storms of his own soul.
"I love the sea, even as my own soul," he writes. "Often do I fancy that the sea is in truth my very soul; and as in the sea there are hidden water-plants that only swim up to the surface at the moment of their bloom and sink down again at the moment of their decay, even so do wondrous flower-pictures swim up out of the depths of my soul, spread their light and fragrance, and again vanish."
In 1826 Heine published the Heimkehr, the Nordsee Cyklus, the airy and sparkling Harzreise, and the first part of the Reisebilder.